Returning to Sport/Dance restoring Energy Availability in RED-S?

Although improvements are being made in raising awareness and in effective medical management of relative energy deficiency in sport (RED-S)[1, 2] what about once an athlete/dancer is “medically cleared” to return to sport/dance? What advice/support is there for athletes/dancers and their coaches/teachers? After discussions with coaches, here are some suggestions on how to achieve return to sport/dance after RED-S.

LifeSeasonDayTo recap, RED-S is a situation of low energy availability (LEA), which can lead to adverse health and performance consequences[3,4]. LEA can be a result of intentional energy restriction, which covers a spectrum of issues with eating from disordered eating to full blown clinical eating disorder. Ironically the original intention of these eating issues may have been to improve athletic performance, yet sustained LEA will ultimately lead to stagnation and deterioration in performance as found in male athletes[5].

The desire to return to full fitness can be a powerful incentive to address LEA. Nevertheless return to sport/dance needs to be carefully structured in collaboration with coaches to prevent injury and avoiding regression to the LEA state.

Structured return to training and nutrition

  • Initially focus should be on body weight strength and conditioning (S&C). Inevitably in RED-S adaptive responses to training stimuli will be dampened due to shut down of hormones networks into an energy saving mode. Once adequate EA has been established, hormone networks will be able to respond. Restoring muscle tone and working on proprioception forms a good basis to build from to mitigate injury risk. Impaired neuromuscular skills have been reported in female athletes in LEA[6], together with adverse effects of LEA on bone health increases injury risk.
  • The other reason for gradual return to training is that a routine of fuelling around training (before, during, after) needs to be established. In particular recovery nutrition within 30 minutes window to enable hormonal responses to training. Note that having this recovery nutrition does not mean reducing intake at the next meal!
  • Long endurance should be eased into after restoring muscle strength and control, in order to prevent injury. Additionally this type of training will necessitate a higher energy requirement. If adequate energy availability has only recently been restored, the balance is fragile and so too much training too soon can have negative effects. Especially if a fuelling strategy around training has not been established as described above.
  • High intensity/interval training should be the last type of training to be resumed as this places the highest stress and requires the highest energy demand on the athlete/dancer.
  • Injury, soft tissue and bone stress responses are more frequent in hormonal dysfunction of RED-S in both male and female athletes[7]. If an injury has been sustained during this period of LEA then particular emphasis needs to be on initial S&C. In the case of previous bone stress responses, multi-direction loading is key to build bone strength before resuming formal run training in athletes who are runners. Even if a bone injury has not occurred, bone turnover is one of the first systems to be adversely impacted by RED-S, so including this type of multidirectional bone loading in the initial structured return for all athletes/dancers would be beneficial.
  • Discuss with your coach a realistic, attainable goal if this will help. Maybe a low key race/event several months down the track

What to look out for

  • Don’t ignore injury niggles, illness or fatigue. Discuss with your coach and back off if necessary. This is a process, not a sprint.
  • Female athletes. You may well have experienced menstrual disruption during your time in LEA. This is a crucial training metric. Please use it! If your menstruation becomes irregular/stops this is your warning sign that your body is not ready to step up training[7]. Male coaches please reinforce this and be aware of this point. Remember Gwen Jorgensen posting her periods on Training Peaks as a training metric?
  • Flexibility in approach. Try not to put pressure on yourself to return to your previous PBs. It is important to have a plan, but you can be flexible. Everyone is different so this process of returning to sport/dance does not have a set, rigid timetable.
  • Enjoyment! Don’t forget the original reason that you started your sport/dance was for enjoyment! This is an opportunity to rediscover that joy, whether you return to competition or not.
  • “Recovery?” Does anyone fully “recover” from disordered eating/eating disorder? I don’t think so. To be a successful athlete, or indeed successful in life you need self-motivation, drive, determination. All admirable qualities, but sometimes these can get diverted to cause unhealthy eating/training patterns. So be aware that in times of stress it may be tempting to revert to old habits of under eating/over exercise to reassure yourself that you are in control.
  • Be prepared for questions: why have you been off training? Why are you not doing fully training schedule? Maybe you want to tell your team mates/friends. Maybe you don’t. That is your call.

So good luck with your return to sport/dance after RED-S, if that is what you want to do. Always discuss with you coach how to approach this.

References

1 BASEM Educational website www.health4perforamnce.co.uk

BJSM blog: Update on RED-S N Keay 2018

3, 4 IOC consensus statements on RED-S BJSM 2014 and update 2018

5 Low energy availability assessed by a sport-specific questionnaire and clinical interview indicative of bone health, endocrine profile and cycling performance in competitive male cyclists. N Keay, G Francis, K Hind. BMJ Open in Sport and Exercise Medicine 2018

5 Reduced Neuromuscular Performance in Amenorrheic Elite Endurance Athletes.
Tornberg Å Melin A Koivula F Johansson A Skouby S et. al.Medicine and science in sports and exercise 2017 vol: 49 (12) pp: 2478-2485

6 Low Energy Availability Is Difficult to Assess but Outcomes Have Large Impact on Bone Injury Rates in Elite Distance Athletes Heikura, Ida A. Uusitalo, Arja L.T. Stellingwerff, Trent et al International Journal of Sport Nutrition and Exercise Metabolism 2018, 28, 4, 403-411

7 What’s so good about Menstrual Cycles? N Keay BJSM blog 2019

How to Identify Male Cyclists at Risk of RED-S?

Relative energy deficiency in sport (RED-S) is a clinical model that describes the potential adverse health and performance consequences of low energy availability (LEA) in male and female athletes. Identification of athletes at risk of LEA can potentially prevent these adverse clinical outcomes.

Athletes at risk of RED-S are those involved in sports where low body weight confers a performance or aesthetic advantage. In the case of competitive road cycling, being light  weight results in favourable power to weight ratio to overcome gravity when cycling uphill. How can male cyclists at risk of LEA be effectively identified in a practical manner?

Energy availability (EA) is defined as the residual energy available from dietary intake, once energy expenditure from exercise training has been subtracted. This available energy is expressed as KCal/Kg fat free mass (FFM). A value of 45 KCal/Kg FFM is roughly equivalent to basal metabolic rate, in other words the energy required to sustain health. In order to quantify EA, accurate measurements of energy intake and expenditure, and FFM assessed from dual X ray absorptiometry (DXA), need to be undertaken. However this is not practical or feasible to undertake all these measurements outside the research setting. Furthermore, methodology for assessing energy intake and expenditure is laborious and fraught with inaccuracies and subjectivity in the case of diet diaries for “free living athletes“. Even if a value is calculated for EA, this is only valid for the time of measurement and does not give any insights into the temporal aspect of EA. Furthermore, an absolute EA threshold has not been established, below which clinical symptoms or performance effects of RED-S occur.

Self reported questionnaires have been shown to be surrogates of low EA in female athletes. However there are no such sport specific questionnaires, or any questionnaires for male athletes. Endocrine and metabolic markers have been proposed as quantitative surrogate measures of EA and shown to be linked to the RED-S clinical outcome of stress fractures in runners. In female athletes the clinical sign of regular menstruation demonstrates a functioning H-P ovarian axis, not suppressed by LEA. What about male athletes? Although hypothalamic suppression of the reproductive axis due to LEA can result in low testosterone, high training loads, in presence of adequate EA, can lead to the same negative effect on testosterone concentration.

Sam

Male cyclists present a further level of complexity in assessing EA status. In contrast to runners, stress fracture will not be an early clinical warning sign of impaired bone health resulting from low EA. Furthermore cyclists are already at risk of poor bone health due to the non weight bearing nature of the sport. Nevertheless, traumatic fracture from bike falls is the main type of injury in cycling, with vertebral fracture requiring the longest time off the bike. Chris Boardman, a serial Olympic medal winner in cycling, retired in his early 30s with osteoporosis. In other words, in road cycling, the combined effect of the lack of osteogenic stimulus and LEA can produce clinically significant adverse effects on bone health.

What practical clinical tools are most effective at identifying competitive male cyclists at risk of the health and performance consequences of LEA outlined in the RED-S model? This was the question our recent study addressed. The lumbar spine is a skeletal site known to be most impacted by nutrition and endocrine factors and DXA is recognised as the “gold standard” of quantifying age matched Z score for bone mineral density (BMD) in the risk stratification of RED-S. What is the clinical measure indicative of this established and clinically significant sign of RED-S on lumbar spine BMD? Would it be testosterone concentration, as suggested in the study of runners? Another blood marker? Cycle training load? Off bike exercise, as suggested in some previous studies? Clinical assessment by interview?

Using a decision tree approach, the factor most indicative of impaired age matched (Z score) lumbar spine BMD was sport specific clinical assessment of EA. This assessment took the form of a newly developed sports specific energy availability questionnaire and interview (SEAQ-I). Reinforcing the concept that the most important skill in clinical medical practice is taking a detailed history. Questionnaire alone can lead to athletes giving “correct” answers on nutrition and training load. Clinical interview gave details on the temporal aspects of EA in the context of cycle training schedule: whether riders where experiencing acute intermittent LEA, as with multiple weekly fasted rides, or chronic sustained LEA with prolonged periods of suppressed body weight. Additionally the SEAQ-I provided insights on attitudes to training and nutrition practices.

Cyclists identified as having LEA from SEAQ-I, had significantly lower lumbar spine BMD than those riders assessed as having adequate EA. Furthermore, the lowest lumbar spine BMD was found amongst LEA cyclists who had not practised any load bearing sport prior to focusing on cycling. This finding is of particular concern, as if cycling from adolescence is not integrated with weight bearing exercise and adequate nutrition when peak bone mass (PBM) is being accumulated, then this risks impaired bone health moving into adulthood.

Further extension of the decision tree analysis demonstrated that in those cyclists with adequate EA assessed from SEAQ-I, vitamin D concentration was the factor indicative of lumbar spine BMD. Vitamin D is emerging as an important consideration for athletes, for bone health, muscle strength and immune function. Furthermore synergistic interactions with other steroid hormones, such as testosterone could be significant.

What about the effects of EA on cycling performance? For athletes, athletic performance is the top priority. In competitive road cycling the “gold standard” performance measure is functional threshold power (FTP) Watts/Kg, produced over 60 minutes. In the current study, 60 minute FTP Watts/Kg had a significant relationship to training load. However cyclists in chronic LEA were under performing, in other words not able to produce the power anticipated for a given training load. These chronic LEA cyclists also had significantly lower testosterone concentration. Periodised carbohydrate intake for low intensity sessions is a strategy for increasing training stimulus. However if this acute intermittent LEA is superimposed on a background of chronic LEA, then this can be counter productive in producing beneficial training adaptations. Increasing training load improves performance, but this training is only effective if fuelling is tailored accordingly.

Male athletes can be at risk of developing the health and performance consequences of LEA as described in the RED-S clinical model. The recent study of competitive male road cyclists shows that a sport specific questionnaire, combined with clinical interview (SEAQ-I) is an effective and practical method of identifying athletes at risk of LEA. The temporal dimension of LEA was correlated to quantifiable health and performance consequences of RED-S.

References 

Low energy availability assessed by a sport-specific questionnaire and clinical interview indicative of bone health, endocrine profile and cycling performance in competitive male cyclists  Keay, Francis, Hind, BMJ Open in Sport and Exercise Medicine 2018

2018 UPDATE: Relative Energy Deficiency in Sport (RED-S) Keay, BJSM 2018

Fuelling for Cycling Performance Science4Performance

Pitfalls of Conducting and Interpreting Estimates of Energy Availability in Free-Living Athletes International Journal of Sport Nutrition and Exercise Metabolism 2018

IOC consensus statement on relative energy deficiency in sport (RED-S): 2018 update BJSM 2018

The LEAF questionnaire: a screening tool for the identification of female athletes at risk for the female athlete triad BJSM 2013

Low Energy Availability Is Difficult to Assess but Outcomes Have Large Impact on Bone Injury Rates in Elite Distance Athletes International Journal of Sport Nutrition and Exercise Metabolism 2018

Treating exercise-associated low testosterone and its related symptoms The Physician and Sports Medicine 2018

Male Cyclists: bones, body composition, nutrition, performance Keay, BJSM 2018

Cyclists: Make No Bones About It Keay, BJSM 2018

Male Athletes: the Bare Bones of Cyclists

Cyclists: How to Support Bone Health?

Synergistic interactions of steroid hormones Keay BJSM 2018

Fuel for the Work Required: A Theoretical Framework for Carbohydrate Periodization and the Glycogen Threshold Hypothesis Sports Medicine 2018

 

Relative Energy Deficiency in Sport (RED-S) 2018 update

What updates are presented in the IOC consensus statement on RED-S 2018?

Prevention

Awareness is the key to prevention. Yet RED-S continues to go unrecognised. Less than 50% of clinicians, physiotherapists and coaches are reported as able to identify the components of the female athlete triad. In a survey of female exercisers in Australia, half were unaware that menstrual dysfunction impacts bone health. Note that these concerning statistics relate to the female athlete triad. Lack of awareness of RED-S in male athletes is even more marked. RED-S as a condition impacting males, as well as females, was described in the initial IOC consensus statement published in 2014. However there is evidence of the occurrence of RED-S in male athletes pre-dating this.

Identification

Identifying an athlete/dancer with RED-S is not always straight forward. In dance or sports where being light weight confers a performance or aesthetic advantage, how can a coach/teacher distinguish between athletes who have this type of physique “naturally” and those who have disordered eating and are at risk of RED-S?  Equally, low energy availability could be a result either of intentional nutrition restriction to control body weight and composition, or an unintentional consequence of not matching an increase in energy expenditure (due to increased training load), with a corresponding increase in energy intake.

Performance effects

Performance is paramount to any athlete or dancer. Apart from physical ability, being driven and determined are important characteristics to achieve success. If weight loss is perceived as achieving a performance advantage, then this can become a competitive goal in its own right: in terms of the individual and amongst teammates. This underlies the interactive effect of psychological factors in the development and progression in the severity of RED-S.

There is both theoretical and practical evidence that short term low energy availability impairs athletic performance as the body is less able to undertake high quality sessions and benefit from the physiological adaptations to exercise. Within day energy deficits have been shown to have adverse effects in both male and female athletes in terms of impact on oestradiol/testosterone and cortisol concentrations. Failure to refuel with carbohydrate and protein promptly after a training session in male runners has been shown to have an adverse effect on bone turnover markers.

To underline the adverse performance effect of low energy availability, a recent study demonstrated that in female athletes, those with functional hypothalamic amenorrhea displayed decreased neuromuscular performance compared to their eumenorrhoeic counterparts. This adverse effect on performance is of particular concern where such skills are crucial in precisely those sports/dance where RED-S is most prevalent. Clearly this situation puts such athletes at increased injury risk, especially if associated with adverse bone mineral density (BMD) due to low energy availability.

Ironically the long term consequences of low energy availability produce adverse effects on body composition: increased fat/lean and reduction in BMD. In other words, the precise opposite effects of what an energy restricted athlete is trying to achieve. In terms of bone health, the lumbar spine is most sensitive to nutrition/endocrine factors (apart from rowers where mechanical loading can attenuate BMD loss at this site in RED-S). Suboptimal BMD is associated with an increased risk of bone injury and therefore impaired performance.

REDs
Keay BJSM 2017

Medical Assessment

Low energy availability is the fundamental issue driving the multi-system dysfunction in the endocrine, metabolic, haematological, cardiovascular, gastrointestinal, immunological and psychological systems in RED-S. However, there are practical issues with directly quantifying energy availability as this is subject to the inaccuracies of reliably measuring energy intake and output. Endocrine and metabolic markers have been shown to more objective indicators of low energy availability, which in turn are correlated to performance outcomes such as bone stress injury in male and female athletes. In the case of female athletes there is an obvious clinical indicator of sufficient energy availability: menstrual cycles. As there is no such obvious clinical sign in male athletes is this why RED-S is less frequently recognised? In both female and male athletes there is some degree of clinical variation: there is no absolute threshold cut off with a set temporal component of low energy availability resulting in amenorrhoea or low testosterone in males. Therefore the IOC recommends that individual clinical evaluation include discussion of nutrition attitudes and practices, combined with menstrual history for females and endocrine markers for male and female athletes will give a very clear indication if an athlete is at risk of/has RED-S.

 

Management

RED-S is a diagnosis of exclusion. Once medical conditions per se have been excluded, RED-S presents a multi-system dysfunction caused by a disrupted periodisation of nutrition/training/recovery. For an athlete the motivation to address these imbalances is to be in a position reach their full athletic potential. This attainment is compromised in RED-S.

Pharmacological interventions are not recommended as first line management in amenorrhoeic athletes. Oral contraception (OCP) masks amenorrhoea with withdrawal bleeds. OCP does not support bone health and indeed may exacerbate bone loss by suppressing further IGF-1. Although transdermal oestrogen, combined with cyclic progesterone does not down regulate IGF-1, nevertheless any hormonal intervention cannot be a long term solution, as bone loss will continue if energy availability is not addressed as a priority.

What next?

The IOC statement suggests further research should include studies with allocation of athletes to intervention groups, with assessment of effects over a substantial time period. Currently a study of competitive male road cyclists over a training/competition season is being undertaken to evaluate the effects of nutrition advice and off bike skeletal loading exercise. Crucially outcome measures will not only be based on bone health and endocrine markers, but measures of performance in terms of power production and race results.

To raise awareness and build support pathways as recommended in the IOC statement,  this is an on going process which requires communication between athlete/dancers, coaches/teachers, parents and healthcare professionals both medical and non medical working with male and female athletes.

References

IOC consensus statement on relative energy deficiency in sport (RED-S): 2018 update BJSM 2018

Male Cyclists: bones, body composition, nutrition, performance BJSM 2018

Male Athletes: the Bare Bones of Cyclists

Addiction to Exercise – what distinguishes a healthy level of commitment from exercise addiction? BJSM 2017

Sports Endocrinology – what does it have to do with performance? BJSM 2017

Within‐day energy deficiency and reproductive function in female endurance athletes Scandinavian Journal of Science and medicine in Sports 2017

The Effect of Postexercise Carbohydrate and Protein Ingestion on Bone Metabolism Translational Journal of the American College of Sports Medicine 2017

Reduced Neuromuscular Performance in Amenorrheic Elite Endurance Athletes Medicine & Science in Sports & Exercise. 49(12):2478–2485, DEC 2017

Cumulative Endocrine Dysfunction in Relative Energy Deficiency in Sport (RED-S) BJSM 2018

Cyclists: Make No Bones About It BJSM 2018

Low Energy Availability is Difficult to Assess But Outcomes Have Large Impact on Bone Injury Rates in Elite Distance Athletes Sports Nutrition and Exercise Metabolism 2017

Part 2: Health, Hormones and Human Performance take centre stage BJSM 2018

Cyclists: How to Support Bone Health?

Healthy Hormones BASEM 2018

 

 

 

Synergistic Interactions of Steroid Hormones

Slide1

The action of the sun on skin is the most effective way of making vitamin D. However, even walking around outside naked for 5 hours every day during UK winter months is not sufficient to make adequate vitamin D. Therefore, much to the relief of the audience at the recent BASEM Spring conference, this was not a strategy recommended by Dr Roger Wolman.

Vitamin D is a fat soluble steroid hormone. The majority of which is synthesised in the skin when exposed to ultraviolet B in sunlight, with a small contribution from dietary sources: this vitamin D3 molecule is then hydroxylated twice in the liver and then kidney to produce the metabolically active form of vitamin D. This activated steroid hormone binds to vitamin D receptors in various tissues to exert its influence on gene expression in these cells. The mono hydroxylated form of vitamin D is measured in the serum, as this has a long half life.

Does it matter having low levels of circulating vitamin D during winter months? What are the solutions if moving to warmer climates during the winter is (unfortunately) not feasible? What are the other hormones interact with vitamin D?

What are the beneficial effects of vitamin D, particularly in the athletic population?

Bone

Rickets and osteomalacia are conditions where vitamin D deficiency results in bone deformities and radiographic appearances are characterised by Looser zones, which in some ways are similar in appearance to stress fractures.

In a large prospective study of physically active adolescent girls, stress fracture incidence was found to have an inverse relationship with serum vitamin D concentrations. In adult female Navy recruits monitored during an 8 week training programme, those on vitamin D supplementation had a 20% reduction in stress fracture. However, oestrogen status was a more powerful risk factor at 91% in those recruits reporting amenorrhoea. Vitamin D is, itself, is a steroid hormone with range of systemic effects. As will be discussed below, its interaction with the sex steroid oestrogen has an important effect on bone turnover.

Immunity

Although sanatoriums, for those suffering with tuberculosis, were based on providing patients with fresh air, any beneficial effect was probably more due to vitamin D levels being boosted by exposure to sunlight. Certainly there are studies demonstrating the inhibitory effect of vitamin D on on slow growing mycobacteria, responsible for TB. What about the influence of vitamin D on other types of infection? In a recent publication, evidence was presented that supplementation with vitamin D prevented acute respiratory tract infections. This effect was marked in those with pre-existing low levels of vitamin D. In a study of athletes a concentration of 95 nmol/L was noted at the cut off point associated with more or less than one episode of illness. In another randomised controlled study of athletes, those supplemented with 5,000IU per day of vitamin D3 during winter displayed higher levels of serum vitamin D and had increased secretion of salivary IgA, which could improve immunity to respiratory infections.

Muscle

There is evidence that supplementing vitamin D3 at 4,000IU per day has a positive effect on skeletal muscle recovery in terms of repair and remodelling following a bout of eccentric exercise. In the longer term, dancers supplemented with 2,000IU over 4 months reported not only reduction in soft tissue injury, but an increase in quadriceps isometric strength of 18% and an increase of 7% in vertical jump height.

Synergistic actions of steroid hormones

No hormone can be considered in isolation. This is true for the network interaction effects between the steroid hormones vitamin D and oestrogen. In a study of professional dancers, there was found to be significant differences in serum vitamin D concentrations in dancers from winter to summer and associated reciprocal relationship with parathyroid hormone (PTH). In situations of vitamin D deficiency this can invoke secondary hypoparathyroidism. Although low levels of vitamin D were observed in the dancers, this was not a level to produce this condition. However, there was an increase in soft tissue injury during the winter months that could, in part, be linked to low vitamin D levels impacting muscle strength.

The novel finding of this study was that female dancers on the combined oral contraceptive pill  (OCP) showed significant differences, relative to their eumenorrhoeic counterparts not on the OCP, in terms of higher levels of vitamin D and associated reductions of bone resorption markers and PTH. The potential mechanism could be the induction by the OCP of liver enzymes to increase binding proteins that alter the proportion of bound/bioactive vitamin D.

This interaction between steroid hormones oestrogen and vitamin D could be particularly significant in those in low oestrogen states such as postmenpoausal women and premenarchal girls. Menarche can be delayed in athletes, so is there a case for vitamin D supplementation in young non-menstruating athletes? What is the situation for men? Do testosterone and vitamin D have similar interactions and therefore implications for male athletes with RED-S, where testosterone can be low?

Vitamin D is not simply a vitamin. It is a steroid hormone with multi-system effects and interactions with other steroid hormones, such as sex steroids, which are of particular relevance to athletes.

References

BASEM Spring Conference 2018 “Health, Hormones and Human Performance”

BASEM Spring Conference 2018 Part 2 “Health, Hormones and Human Performance”

Calcium and Vitamin D Supplementation Decreases Incidence of Stress Fractures in Female Navy Recruits JBMR 2009

Vitamin D, Calcium, and Dairy Intakes and Stress Fractures Among Female Adolescents Arch Pediatr Adolesc Med 2012

A Single Dose of Vitamin D Enhances Immunity to Mycobacteria American Journal of Respiratory and Critical Care Medicine 2007

Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data BMJ 2017

Influence of vitamin D status on respiratory infection incidence and immune function during 4 months of winter training in endurance sport athletes Exerc Immunol Rev. 2013

The effect of 14 weeks of vitamin D3 supplementation on antimicrobial peptides and proteins in athletes J Sports Sci. 2016

A systems-based investigation into vitamin D and skeletal muscle repair, regeneration, and hypertrophy American Journal of Physiology 2015

The influence of winter vitamin D supplementation on muscle function and injury occurrence in elite ballet dancers: A controlled study Journal of Science and Medicine in Sport 2014

Vitamin D status in professional ballet dancers: Winter vs. summer J Science and Medicine in Sport 2013

Cyclists: How to Support Bone Health?

Screen Shot 2018-02-25 at 16.51.20.png
Supporting Bone Health

The wonderfully named “hip hop” study was conducted to investigate whether hopping would improve the strength of the hip bone in older males. You may be wondering how this is relevant to male cyclists in their twenties. Yet, in a recent pilot study, some male cyclists were found to have areas of the skeleton that were below average bone mineral mineral (BMD) for an 85 year old man. This finding of low BMD in cyclists was confirmed in a recent BBC programme where Dr Karen Hind at Leeds Beckett University presented the differences in BMD across sports. Keen-eyed cyclists amongst you will have recognised Ed Clancy from JLT Condor representing cyclists, though these findings will be relevant to all levels of competitive cyclists.

So maybe research with the same aims as the “hip hop” study is exactly what needs to be conducted amongst male cyclists to investigate practical and effective ways of supporting bone health and ultimately preventing injury and optimising performance. This is aim of forthcoming research in collaboration with Dr Hind.

webmd_rm_photo_of_porous_bones
Microscopic structure of bone

In common with other sports, cycling is an excellent form of exercise, driving positive adaptations throughout the body, such as improved cardiovascular fitness, body composition, muscular strength and endurance together with beneficial psychological effects. However, unlike many other forms of exercise, cycling does not encourage beneficial adaptations to the full skeletal system. This is due to a lack of mechanical osteogenic (bone building) stimuli provided in cycling, particularly at the lumbar spine. In competitive road cycling, low body mass confers a performance advantage, so restrictive or inconsistent nutrition can lead to relative energy deficiency in sport (RED-S). The consequent Endocrine system dysfunction can compound the negative effects on bone health of a non-load-bearing sport.

In a study of masters cyclists, decreases in BMD at all sites were more marked than in sedentary individuals. Some cyclists went from being osteopenic to osteoporotic; a rare case where exercise has a negative impact on a system in the body. Does this matter? Like all athletes, cyclists are more concerned with current athletic performance than warnings about future issues, such as osteoporosis and fracture. Yet, out of athletes across all sports, cyclists should perhaps be the most concerned. In the case of runners, suboptimal bone heath and associated RED-S may well present as a stress fracture. In the case of cyclists by the nature of non-load bearing exercise, they can push for longer with suboptimal bone and nutritional status. The full extent of any bone health issues may only come to light as result of a bike crash. Looking at the time off from injury in elite cyclists, the majority are due to fracture, with vertebral fractures often requiring long duration of recovery compared to other sites.

Maybe maintenance of BMD for adult cyclists would be realistic goal. How can this be achieved?

Multidirectional, dynamic loading patterns have been shown to produce the most positive skeletal responses. This is seen in the different site specific effects of sports, where changes of direction or plane of movement provide maximal mechanical osteogenic stimulus. Jumping and hopping have been shown to be good for bone health in premenopausal women, where brief high impact exercises were found to be beneficial for the bone mineral density (BMD) of the femoral neck of the hip.

What about targeting the lumbar spine, which is the site most at risk in cyclists? In young children, a few mechanical loading cycles of two-footed jumping from a small step improved BMD at lumbar spine compared with those that did not perform this jumping exercise. However bone is at its most responsive in childhood and skeletal loading has a more long term effect on both microarchitecture and BMD than when performed as an adult. Nevertheless, even in adulthood bone is still a dynamic tissue, able to adapt to loading stresses. Resistance training seems to be the most effective way of providing mechanical osteogenic stimulus to the lumbar spine with an additional indirect osteogenic effect of muscle pulling on bone. For example rowers have site-specific increases in BMD at the lumbar spine. In a recent study, resistance training was found to improve BMD in male distance runners with similar levels of testosterone and bone markers. This concurs with recent pilot study of cyclists, where those performing current resistance training or with recent history of participating in other sports, such as rugby or rowing, fared better in terms of BMD. In other words, the improvement in BMD mediated via mechanical rather than Endocrine effects.

Nevertheless, any form of skeletal-loading exercise will not produce the expected beneficial osteogenic effect, if performed in suboptimal nutritional status. Sufficient quantity and quality of nutrition are required to prevent RED-S. Specific nutritional factors, such as vitamin D, calcium and polyphenols, are recognised to be important in bone health. Boron is also described as decreasing bone resorption by stabilising and extending the half-life of vitamin D and improving sex steroid availability. Whilst high intake of caffeine, which can accumulate if athletes take on board caffeine gels, has a negative impact on BMD. Optimal nutritional status will in turn support the Endocrine system to mediate advantageous adaptations to exercise exercise, including bone health.

How can cyclists optimise bone health and performance on the bike with consistent and targeted skeletal-loading exercise and nutritional strategies? Watch this space! A study is planned to investigate practical and effective strategies to achieve this. No on bike hip hop dance required.

In meantime there will be more discussion on “Health, Hormones and Human Performance” at the BASEM conference 22 March. All welcome, including athletes and coaches, alongside healthcare professional working with athletes.

References

Male Athletes: the Bare Bones of Cyclists

Cyclists: Make No Bones About It BJSM 2018

Which type of exercise gives you the strongest bones? BBC

Studies

Male Cyclists: Bones, Body composition, Nutrition, Performance BJSM 2018

Longitudinal Changes in Bone Mineral Density in Male Master Cyclists and Nonathletes The Journal of Strength & Conditioning Research 2011

A meta-analysis of brief high-impact exercises for enhancing bone health in premenopausal women  Osteoporosis International 2012

Jumping Improves Hip and Lumbar Spine Bone Mass in Prepubescent Children: A Randomized Controlled Trial JBMR 2001

Review Exercise and Sports Science Australia (ESSA) position statement on exercise prescription for the prevention and management of osteoporosis Journal of Science and Medicine in Sport 2016

Resistance training is associated with higher bone mineral density among young adult male distance runners independent of physiological factors The Journal of Strength & Conditioning Research 2018

Relative Energy Deficiency in Sports (RED-S) Practical considerations for endurance athletes

Nothing Boring About Boron Integrated Medicine 2015

Cumulative Endocrine Dysfunction in Relative Energy Deficiency in Sport (RED-S) BJSM 2018

Male Athletes: the Bare Bones of Cyclists

Chris Boardman is an Olympic gold medal winner and world record breaking cyclist. However, he explains in his biography that he retired in his early thirties with weak bones and low testosterone. At the time he was treated with medication aimed at improving his bone strength, but this severely impacted his performance on the bike.

What was the cause of this superlative male athlete’s unhealthy condition that ultimately lead to his retirement? Is this still an issue for male cyclists today? Is it limited to elite professional riders?

Slide1
Periodisation of key training factors support the Endocrine system to optimise performance

In 2014 the IOC published a description of relative energy deficiency in sports (RED-S), where nutrition intake is insufficient to cover training demands and the basic “housekeeping” activities of the body. This induces an energy-saving mode that impacts health and therefore athletic performance. The female athlete triad had been previously described as the combination of disordered eating, menstrual disruption and impaired bone health. RED-S goes beyond the female athlete triad to include a broader range of  impacts on systems other than just the bones and female hormone production. Significantly RED-S includes male athletes. Today, Chris Boardman would be diagnosed with RED-S.

Has this new information improved the identification and support of male athletes at risk of RED-S? In a recent pilot study, 5 out of 10 competitive amateur riders (Category 2 and above) were in the lowest age-matched percentile of body fat and 9 out 10 where in the lowest 6% relative to the population of similar age. Significantly, 7 out of 10 riders had below-average for age bone mineral density (BMD) in the lumbar spine, with two males having bone densities that would be low for an 85 year old.

Why is poor bone health a particular risk for competitive male cyclists? Depending on the type of exercise, beneficial adaptations include mechanical strengthening of specific parts of the skeletal system. For example, assuming good nutrition, runners tend to have strong hips, whereas rowers have more robust spines in terms of BMD and bone microarchitecture. Conversely the non-weight-bearing nature of cycling and the generally lower level of upper-body musculature reduce the mechanical loading forces though the spine: low osteogenic (bone building) stimuli. Although similar to swimming, in the sense that body weight is supported in the water, the major difference between these two forms of exercise is that in cycling, particularly for climbing, low body mass confers a performance advantage. This brings in the additional factor for bone health of potential inadequacies in nutrition and therefore consequences on hormone production.

An optimal balance of training, nutrition and recovery drives beneficial adaptations to exercise throughout the body. The body’s Endocrine system releases hormones that stimulate positive changes, such as the process of improving the efficiency of delivering and utilising oxygen and nutrients to exercising tissues, including the skeletal system. Any imbalances in periodisation between the three inputs of training, nutrition and recovery will compromise health and athletic performance.

Cyclists are at particular risk of insufficient fuelling. This may be an intentional attempt to maintain low body weight, which can lead to healthy eating becoming an unhealthy orthorexic pattern, where vital food groups for endurance sport, such as carbohydrates are excluded. There is also a practical element to fuelling adequately during long rides and refuelling afterwards. Consistency of nutrition throughout the day has been highlighted in a recent study of male endurance athletes where although an average 24 hour intake may be sufficient, if there are any significant deficits during this time, then this is reflected in increased adverse impact on catabolic Endocrine makers. In another study of male athletes if refuelling with carbohydrate and protein after training did not occur promptly, this lead to an increase in bone resorption over formation markers.

Recovery is an essential part of a training schedule, because the adaptations to exercise occur during rest. Sleep, in particular, is a major stimulus for growth hormone release, which drives positive adaptive changes in terms of body composition and bone turnover. Conversely, insufficient recovery time due to a packed schedule of training and work, places extra stresses on the Endocrine system. Getting to bed half an hour earlier than usual every day quickly adds up to an extra night’s sleep.

Does it matter if some areas of the skeleton are weaker than others? Yes, because this increases your risk of fracture, not just if you come off your bike, but also with relatively low force impacts. In the case of runners and triathletes, bone stress injuries are more likely to occur as an early warning sign of impaired bone health due to RED-S. Since low impact forces are absent in cycling, it may take a crash to reveal the strength of a rider’s bones. Studying the list of injuries in elite cyclists there are many fractures, with longer recovery time for vertebral fractures. So potentially cyclists can develop more severe bone health issues than other athletes, before becoming aware of the situation.

If you are a male cyclist, what can you do to prevent issues of bone health and risk of developing RED-S and suboptimal performance on the bike? Watch this space! A study is planned to investigate practical and effective strategies to optimise health and performance on the bike. In meantime there will be more discussion on “Health, Hormones and Human Performance” at the BASEM conference 22 March. All welcome, including athletes and coaches, alongside healthcare professional working with athletes.

References

Mechanisms for optimal health…for all athletes! BJSM 2017

Optimal health: including female athletes! Part 1 Bones BJSM 2017

Optimal health: including male athletes! Part 2 Relative Energy Deficiency in sports BJSM 2017

Lifestyle Choices for optimising health: exercise, nutrition, sleep BJSM 2017

Sports Endocrinology – what does it have to do with performance? BJSM 2017

Relative Energy Deficiency in Sports (RED-S) Practical considerations for endurance athletes

Within-day Energy Deficiency and Metabolic Perturbation in Male Endurance Athletes International Journal of Sport Nutrition and Exercise Metabolism 2018

The Effect of Postexercise Carbohydrate and Protein Ingestion on Bone Metabolism Translational Journal of the American College of Sports Medicine 2017

Sleep for health and sports performance BJSM 2017

 

 

 

Male Cyclists: Bones, Body composition, Nutrition, Performance

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There has been much recent coverage regarding female runners suffering with health and performance issues due to relative energy deficiency in sports (RED-S). What about male athletes? A recent article about male cyclists who explained how they developed RED-S, did not receive as sympathetic a response as articles concerning female athletes. Yet multiple Endocrine network disruption in RED-S, associated with suboptimal health and performance, is equally applicable to male and female athletes.

Although competitive road cycling is excellent for cardiovascular (CV) fitness, why are male cyclists at particular risk of impaired bone health and RED-S? Cycling is a non-weight bearing type of exercise, as is swimming, so does not provide much osteogenic (bone building) stimulus. The additional element in road cycling is that, in the short term, low body weight, with associated low body fat, confers a performance advantage. However this can lead to restrictive nutrition and RED-S, that have adverse effects on health and performance, over the longer term.

A recent study looking at bone acquisition in adolescent males found that bone mass, microarchitecture and makers of bone formation were more favourable in footballers compared with cyclists and swimmers. Swimmers had the lowest Vitamin D, presumably as this is generally an indoor sport (unless you live in Australia where outdoor 50m pools abound). Another study found reduction in femoral neck bone mineral accumulation in adolescent male cyclists compared against increases over the same time frame seen in controls.

What about adult male road cyclists? When runners and cyclists were matched for age and body weight, there were no significant differences in hormone or nutrition status, yet cyclists were 7 times more likely to have osteopenia of the lumbar spine than runners. Similar results were found in another study where competitive male road cyclists were found to have reduced lumbar spine bone mineral density (BMD) for age, despite normal levels of testosterone and insulin-like growth factor 1 (IGF1), although intriguingly an inverse correlation with lumbar spine BMD and IGF1 was found. It appears that the biomechanical stress patterns on the spine in cycling are not oesteogenic in nature, which contrasts with rowing where, although also seated, the biomechanical load exerted through the spine does provide an osteogenic effect.

In addition to the non-load bearing nature of cycling on the skeleton, restrictive nutrition can contribute to suboptimal bone health. Reducing energy availability by restricting energy intake whilst increasing training load can be a strategy, especially during pre-season training to reduce body weight and body fat. Essentially, cycling up a steep incline demands less power through the pedals if your body weight is low. Nevertheless, reducing energy availability runs the risk of developing RED-S, associated Endocrine dysfunction and suboptimal bone health, on top of the non-beneficial mechanical osteogenic effect of cycling. On a practical note, with long training rides in the saddle it can be physically and practically difficult to fuel optimally. Recent research in female athletes shows that within day energy deficits magnify hormonal disruption. Could this be a factor in male cyclists where consistent fuelling is either actively avoided and/or practically difficult?

The psychological element of disordered eating has been described amongst elite male cyclists. Male cyclists, in particular, collect many metrics associated with training and racing which could be a manifestation of a drive to perfectionism. Determination and attention to detail are laudable qualities for athletes, but there is a fine line when the balance swings to behaviours and attitudes that can be detrimental to health and performance. Even starting off with good intentions can lead to problems as seen with the growing emergence of orthorexia: “clean eating”, which, ironically, becomes detrimental to health and performance with exclusion of food groups such as carbohydrates.

Exclusively practising a non weight bearing sport such as cycling although great for CV fitness, is not so good for bone health. Does this matter? Potentially injury is more likely in bike spills, which occur both in training and competition even for the most experienced bike handler. Combined with the drive for low body weight in competitive road cycling, health and performance issues can be compounded with RED-S. What are the solutions for the cyclist to support favourable body composition and bone health, which ultimately also optimises performance? A further planned study, following a current pilot study of competitive road cyclists, aims to investigate the potential beneficial effects of strength and conditioning to load the skeleton combined with a review of nutrition. See details of next study to see if you wish to participate.

For more discussion on the Endocrine aspects of Sports and Exercise Science and Medicine, BASEM Spring conference 22 March 

References

Cumulative Endocrine Dysfunction in Relative Energy Deficiency in Sport (RED-S)

Optimal health: including male athletes! Part 2 Relative Energy Deficiency in sports BJSM 2017

Too healthy to ride? How clean living could slow you down Cycling Weekly 2017

Body Composition for Health and Sports Performance

Longitudinal Adaptations of Bone Mass, Geometry, and Metabolism in Adolescent Male Athletes: The PRO-BONE Study JBMR 2017

Bone Related Health Status in Adolescent Cyclists Plos 2011

Participation in road cycling vs running is associated with lower bone mineral density in men Metabolism 2008

Evaluation of the Bone Status in High-Level Cyclists Journal of Clinical Densitometry 2012

Effect of exercise training programme on bone mineral density in novice college rowers BJSM 1995

Energy Intake and Energy Expenditure of Elite Cyclists During Preseason Training Int J Sports Med 2005
Kings and Queens of the Mountains Science4Performance 2017

Cumulative Endocrine Dysfunction in Relative Energy Deficiency in Sport (RED-S)

Perfectionism and Risk for Disordered Eating among Young French Male Cyclists of High Performance Perceptual and Motor Skills 2004

Kings and Queens of the Mountains Science4Performance 2017

Addiction to Exercise – what distinguishes a healthy level of commitment from exercise addiction? BJSM 2017

Optimal Health: For All Athletes! Part 4 – Mechanisms BASEM 2017

 

 

 

 

 

Cumulative Endocrine Dysfunction in Relative Energy Deficiency in Sport (RED-S)

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Unfortunately I continue to see athletes, both male and female, whose health and athletic performance is hampered due to Relative Energy Deficiency in Sports (RED-S). There have been some high profile athletes who have been very open about how RED-S has affected them, alerting younger athletes to potential pitfalls.

Does this issue warrant highlighting? Yes! The athletes I see and those that speak out are only just the tip of the iceberg. In a study of exercising females, half were found to have subtle menstrual hormone disruption such as luteal phase deficit or anovulation. A third were amenorrhoeic, with no periods at all. All women of reproductive age, whether an athlete or not, should have regular periods, otherwise there are potential serious health and performance sequaelae. However studies in both the USA and Australia have revealed that the majority of young exercising women are not aware of the link between menstrual disruption and deleterious, potentially irreversible effects on bone health.

The impact of non-integrated periodisation of training, nutrition and recovery has evolved since the early description of the female athlete triad. The constellation of amenorrhoea, disordered eating and osteoporosis is now considered to be a clinical spectrum. In turn the female athlete triad is part of a much broader picture of RED-S, which includes adverse multi-system effects beyond bone health and is also seen in male athletes.

Although an athlete may appear healthy, what are the underlying Endocrine disruptions occurring in RED-S that ultimately will impede both optimal health and performance to full potential? In general, female exercisers are more susceptible to internal and external perturbations as the female Endocrine system is more finely balanced than in males. Nevertheless, in a study of male athletes, in the short time period after completing a training session, bone turnover was adversely affected, with an increase in markers of resorption relative to formation, if an athlete did not refuel rapidly with protein and carbohydrate. In the now classic research by Loucks, 5 days of manipulated energy restricted availability, via dietary intake and exercise output, caused disruption in LH pulsatility in previously eumenorrhoeic women. From this research and subsequent studies, not only is the reproductive axis disrupted with reduced energy availability, in addition hypothalamus-pituitary-thyroid (decreased T3) and adrenal axes (increased cortisol) and decreased IGF1 due to relative GH resistance are all disrupted. These interactive hormonal dysfunctions occur even before reduction in sex steroids. A recent study demonstrated that beyond the average energy availability over a 24 hour time window, within day energy deficits in terms of duration and magnitude are associated with a greater degree of disruption of Endocrine and metabolic markers, in particular decreased oestradiol and increased cortisol. So consistency of nutrition, not only during a training season but from day to day is vital.

Although energy availability is the crucial factor in the pathophysiology of RED-S, measuring this is not practical for all athletes in terms of accuracy and cost. Clinical menstrual status in female athletes and basic Endocrine markers are proposed as being more reliable and accessible. The Endocrine system is very sensitive to internal and external perturbations, as described above, and presages performance consequences of RED-S, such as injury. An important starting point is for all female athletes is to ask themselves: are my periods regular? This is also a vital question that coaches and parents need to consider for athletes in their care. If the answer is no, then this needs to be assessed, ideally by those with experience in Sports Endocrinology.

Why are these clinical and biochemical markers of Endocrine dysfunction important for athletes? Essentially there are significant health and performance implications for athletes. As outlined in the stories of female athletes, by the time career limiting stress fractures become obvious, typically in early twenties, the Endocrine system has been in disarray for a significant time. Long term, irreversible poor bone health and adverse body composition have been established.

In my opinion, emphasis should be placed on the positive outcome of integrating periodised training, nutrition and recovery to support a functional Endocrine system and therefore optimal health and ability to reach full athletic potential. For example for female athletes, competing in sports where low body mass confers a performance advantage, such as ballet, gymnastics and road cycling, finely tuned neuromuscular skills are essential to reach maximal potential and minimise injury risk. Yet these are the athletes most at risk of developing RED-S, with consequential adverse effects on menstrual cycles, endogenous oestrogen secretion and neuromuscular function.

Rather than reading headlines about the concerning health issues amongst athletes, more guidance for athletes and those working with them, on the warning signs and how to combat RED-S are needed so that athletes can reach their full potential and the headlines become about athlete achievements.

For more discussion on the Endocrine and Metabolic aspects of Sport and Exercise Medicine, all members of multi-disciplinary team working with athletes, including athletes and coaches are welcome to the BASEM Spring Conference

BAsem2018_SpringConf_BJSM

References

Relative Energy Deficiency in Sports (RED-S) Practical considerations for endurance athletes

British middle-distance runner Bobby Clay is struggling with osteoporosis but wants her experience to act as a lesson for fellow young athletes Athletics Weekly 2017

In a special AW report, former English Schools champion Jen Walsh reveals the devastation that the female athlete triad can wreak Athletics Weekly 2017

Optimal Health: Especially Young Athletes! Part 3 – Consequences of Relative Energy Deficiency in Sports BASEM 2017

Prevalence High prevalence of subtle and severe menstrual disturbances in exercising women: confirmation using daily hormone measures. Human Repro 2010

Energy deficiency, menstrual disturbances, and low bone mass: what do exercising Australian women know about the female athlete triad? Int J Sport Nutr Exerc Metab. 2012

Female adolescent athletes’ awareness of the connection between menstrual status and bone health J Pediatr Adolesc Gynecol. 2011

Optimal health: including female athletes! Part 1 Bones BJSM 2017

Optimal Health: For All Athletes! Part 4 – Mechanisms BASEM 2017

Optimal health: including male athletes! Part 2 Relative Energy Deficiency in sports BJSM 2017

Sports Endocrinology – what does it have to do with performance? BJSM 2017

The Effect of Postexercise Carbohydrate and Protein Ingestion on Bone Metabolism Translational Journal of the American College of Sports Medicine 2017

Luteinizing hormone pulsatility is disrupted at a threshold of energy availability in regularly menstruating women JCEM 2003

Within-day energy deficiency and reproductive function in female endurance athletes Scandinavian Journal of Science and medicine in Sports 2017

Low Energy Availability is Difficult to Assess But Outcomes Have Large Impact on Bone Injury Rates in Elite Distance Athletes Sports Nutrition and Exercise Metabolism 2017

Body Composition for Health and Sports Performance

Reduced Neuromuscular Performance in Amenorrheic Elite Endurance Athletes Medicine & Science in Sports & Exercise 2017

Internal Biological Clocks and Sport Performance

A Nobel Prize was awarded this week to researchers who uncovered the molecular mechanisms controlling circadian rhythm: our internal biological clock.

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Circadian Hormone Release

These mechanisms rely on negative feedback loops found in many biological systems where periodicity of gene expression is key, such as the Endocrine system. Internal biological clocks allow for anticipation of the requirements from body systems at different times of the day and the ability to adapt to changes in external lifestyle factors. What is the clinical significance of biochronometers?

The importance of integration of lifestyle factors, such as timing of eating, activity and sleep with our internal biological clocks is revealed in situations of circadian misalignment that lead to suboptimal health and disease states in the longer term.

Consideration of our biochronometers is especially important for athletes in order to synchronise periodised training, nutrition and recovery and thus optimise health and sports performance.

Athletic Performance Performance in a cycle time trial was found to be better in the evening, rather than the morning, proposed to be due to a more favourable endogenous hormonal and metabolic internal milieu. Certainly there were some disgruntled swimmers at an international event, when the usual pattern of morning heats and evenings finals was switched, to accommodate television viewing spectators.

Female athletes: menstrual cycle/training season Women have an extra layer of endogenous biological periodicity in the form of the menstrual cycle controlled by temporal changes of hormone release in the hypothamalmus-pituitary-ovarian Endocrine axis. Changes in external factors of training load, nutrition and recovery are detected by the neuroendocrine gatekeeper, the hypothalamus, which produces an appropriate change in frequency and amplitude of GnRH (gonadotrophin releasing hormone), which in turn impacts the pulsatility of LH (lutenising hormone) release from the pituitary and hence the phases of the menstrual cycle, in particular ovulation. Even short term reduction of energy availability in eumenorrhoeic female athletes can inhibit LH pulsatility frequency and release of other hormones such as IGF1. Disrupted release of sex steroids and IGF1 has a negative effect on bone turnover: increased resorption and decreased formation. Active females have been found more susceptible to reduction in energy availability impacting bone metabolism than their male counterparts.

Another consequence of the phasic nature of the menstrual cycle relating to external factors such as exercise, is that injury risk could be linked to changes in the expression of receptors for for sex steroids oestrogen and progesterone in skeletal muscle. Certainly during pregnancy and the post partum period, relaxin hormone increases the laxity of soft tissues, such as ligaments, and hence maintenance stretching, rather than seeking to increase flexibility, is recommended to prevent injury, .

In order to produce desired temporal adaptive changes in response to exercise training, signalling pathways mediated by reactive oxidative species and inflammatory markers are stimulated in the short term, with supportive Endocrine interactions in the longer term. However, an over-response can impair adaptive changes and impact other biological systems such as the immune system. This maladaptive response could occur as a result of non-integrated periodisation of training, nutrition and recovery in athletes and, in the case of female athletes, oral contraceptive pill use has been implicated, as this effectively imposes a medical menopause, preventing the phasic release of endogenous hormones.

Considering a longer time scale, such as a training season, female athletes were found to have a more significant fall ferritin during than male athletes. Low normal iron does not necessarily correlate to iron deficiency anaemia, but low levels in athletes can impact bone health. Supplementation with vitamin C to improve absorption may help, although iron overload can have deleterious effects. As training intensity increases as the season progresses, six monthly haematological reviews for female athletes were recommended in this study.

Changes in set point feedback Feedback control of the Endocrine system, for example the hypothalamic-pituitary-thyroid axis is dynamic: both anticipatory and adaptive, depending on internal and external inputs. However, presentation of a prolonged stimulus can result in maladaptation in the longer term. For example, disruption of signalling pathways leading to hyperinsulinaemia results in insulin resistance, which represents the underlying pathophysiological mechanism of obesity and the metabolic syndrome. In other words a situation of tachyphylaxis, where prolonged, repeated stimulus over time results in insensitivity to the original stimulus. This also applies to the nature of exercise training over a training season and diets that exclude a major food type: temporal variety is key.

Lifespan (prematurity, ageing) Changes during the lifespan represent an important biochronometer. Premature and small-for-dates babies are at risk of long term metabolic and Endocrine dysfunction, potentially due to intrauterine reprogramming of the hypothalamic-pituitary axis. At the other end of the biological time scale, with advancing age, DNA methylation and changes in epigenetic expression occur. It has been suggested that this age related methylation drift could be delayed with calorie restriction. Melatonin, a key player in intrinsic biological time keeping has been proposed to attenuate bone resorption by reducing relative oxidative stress. This would potentially explain why shift workers with disrupted sleep patterns are reported to be at risk not only of metabolic dysfunction, but also impaired bone health. Disrupted sleep patterns are a concern for athletes, especially those whose training and competition schedule involve frequent international travel across time zones.

In summary, respecting your internal biological clocks and integrating your lifestyle and your training, nutrition and recovery with these intrinsic pacemakers in mind will optimise health and performance.

References

The Nobel Prize in Physiology or Medicine 2017

Circadian clock control of endocrine factors Nat. Rev. Endocrinol

Temporal considerations in Endocrine/Metabolic interactions Part 1 Dr N. Keay, British Journal of Sports Medicine 2017

Temporal considerations in Endocrine/Metabolic interactions Part 2 Dr N. Keay, British Journal of Sports Medicine 2017

Athletic Fatigue: Part 2 Dr N. Keay 2017

Effect of Time of Day on Performance, Hormonal and Metabolic Response during a 1000-M Cycling Time Trial Plos One 2017

Optimal Health: For All Athletes! Part 4 – Mechanisms Dr N. Keay, British Association of Sport and Exercise Medicine 2017

Effects of reduced energy availability on bone metabolism in women and men Bone 2017

Expression of sex steroid hormone receptors in human skeletal muscle during the menstrual cycle Acta Physiol (Oxf). 2017

Endocrine system: balance and interplay in response to exercise training

Kynurenic acid is reduced in females and oral contraceptive users: Implications for depression Science Direct 2017

Oxidative Stress in Female Athletes Using Combined Oral Contraceptives Sports Medicine

Iron monitoring of male and female rugby sevens players over an international season J Sports Med Phys Fitness. 2017

Thyroid Allostasis–Adaptive Responses of Thyrotropic Feedback Control to Conditions of Strain, Stress, and Developmental Programming Frontiers in Endocrinology 2017

Stress- and allostasis-induced brain plasticity Annu Rev Med

Optimising Health and Athletic Performance Dr N. Keay 2017

Long-term metabolic risk among children born premature or small for gestational age Nature Reviews Endocrinology 2017

Caloric restriction delays age-related methylation drift Nature Communications 2017

Melatonin at pharmacological concentrations suppresses osteoclastogenesis via the attenuation of intracellular ROS Osteoporosis International 2017

Sleep for health and sports performance Dr N. Keay, British Journal of Sports Medicine 2017

 

Optimising Health and Athletic Performance

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In order to improve sports performance, athletes periodise their training, nutrition and recovery within the context of a training season. For those not in exercise training, these controllable lifestyle factors correspond to exercise, diet and sleep, which require modification during the lifespan. In old money, this was called preventative medicine. Taking this a step further, rather than preventing disease, this proactive, personalised approach optimises health. Health should be a positive combination of physical, mental and social well being, not simply an absence of illness.

Failure to balance these lifestyle factors in an integrated fashion leads to negative outcomes. An athlete may experience maladaptation, rather than the desired adaptations to exercise training. For non-athletes an adverse combination of lifestyle factors can lead to suboptimal health and a predisposition to developing chronic disease.

What are the fundamental pathophysiological mechanisms involved in the aetiology of the clinical spectrum of suboptimal health, suboptimal sports performance and chronic disease?

Inflammation A degree of systemic inflammation and oxidative stress induced by exercise training is required to drive desired adaptations to support improved sport performance. However, prolonged, elevated levels of inflammation have adverse effects on health and underpin many chronic disease states. For example, inflammation is a contributing pathophysiological factor in the development of atherosclerosis and atherothrombosis in cardiovascular disease. What drives this over-response of the inflammatory process? Any combination of adverse lifestyle factors. Adipose tissue has an Endocrine function, releasing a subgroup of cytokines: adipokines which have peripheral and central signalling roles in energy homeostasis and inflammation. In a study of Belgian children, pro-inflammatory energy related biomarkers (high leptin and low adiponectin) were associated with decreased heart rate variability and hence in the long term increased risk of cardiovascular disease. For those with a pre-existing chronic inflammatory condition, response to treatment can be optimised with personalised lifestyle interventions.

Metabolism Non-integrated lifestyle factors can disrupt signalling pathways involved in glucose regulation, which can result in hyperinsulinaeamia and insulin resistance. This is the underlying pathological process in the aetiology of metabolic syndrome and metabolic inflexibility. Non-pharmacological interventions such as exercise and nutrition, synchronised with endogenous circadian rhythms, can improve these signalling pathways associated with insulin sensitivity at the mitochondrial level.

Intriguingly, evidence is emerging of the interaction between osteocalcin and insulin, in other words an Endocrine feedback mechanism linking bone and metabolic health. This is reflected clinically with increased fracture risk found amongst type 2 diabetics (T2DM) with longer duration and higher HbA1C.

Hormone imbalance The hypothalamus is the neuroendocrine gatekeeper of the Endocrine system. Internal feedback and external stimuli are integrated by the hypothalamus to produce an appropriate Endocrine response from the pituitary gland. The pathogenesis of metabolic syndrome involves disruption to the neuroendocrine control of energy homeostasis with resistance to hormones secreted from adipose tissue (leptin) and the stomach (ghrelin). Further evidence for the important network effects between the Endocrine and metabolic systems comes from polycystic ovarian syndrome (PCOS). Although women with this condition typically present to the Endocrine clinic, the underlying aetiology is metabolic dysfunction with insulin resistance disrupting the hypothamic-pituitary-ovarian axis. The same pathophysiology of disrupted metabolic signalling adversely impacting the hypothalamic-pituitary-gonadal axis also applies to males.

In athletes, the exact same signalling pathways and neuroendocrine systems are involved in the development of relative energy deficiency in sports (RED-S) where the underlying aetiology is imbalance in the periodisation of training load, nutrition and recovery.

Gastrointestinal tract In addition to malabsorption issues such as coeliac disease and non-gluten wheat sensitivity, there is emerging evidence that the composition and diversity of the gut microbiota plays a significant role in health. The microbiome of professional athletes differs from sedentary people, especially at a functional metabolic level. Conversely, an adverse gut microbiome is implicated in the pathogenesis of metabolic dysfunction such as obesity and T2DM, via modulation of enteroendocrine hormones regulating appetite centrally and insulin secretion peripherally.

Circadian disregulation As previously discussed, it is not just a question of what but WHEN you eat, sleep and exercise. If there is conflict in the timing of these lifestyle activities with internal biological clocks, then this can disrupt metabolic and endocrine signally. For example, in children curtailed sleep can impact glucose control and insulin sensitivity, predisposing to risk of developing T2DM. Eating too close to the onset of melatonin release in the evening can cause adverse body composition, irrespective of what you eat and activity levels. In those with pre-existing metabolic dysfunction, such as PCOS, timing of meals has an effect on insulin levels and hence reproductive Endocrine function. The immune system displays circadian rhythmicity which integrated with external cues (for example when we eat/exercise/sleep) optimises our immune response. For athletes competing in high intensity races, this may be more favourable in terms of Endocrine and metabolic status in the evening.

Psychology Psychological stress impacts the key pathophysiological mechanisms outlined above: metabolic signalling, inflammation and neuroendocrine regulation, which contribute to Endocrine and metabolic dysfunction. Fortunately stress is a modifiable lifestyle risk factor. In the case of functional hypothalamic amenorrhoea (where nutrition/exercise/sleep are balanced), psychological intervention can reverse this situation.

Conclusion Putting this all together, if the modifiable lifestyle factors of exercise, nutrition, sleep are optimised in terms of composition and timing, this improves metabolic and Endocrine signalling pathways, including neuroendocrine regulation. Preventative Medicine going beyond preventing disease; it optimises health.

BASEM annual conference 22/3/18: Health, Hormones and Human Performance

Presentations

References

Athletic Fatigue: Part 2 Dr N. Keay

From population based norms to personalised medicine: Health, Fitness, Sports Performance Dr N. Keay, British Journal of Sports Medicine 2017

Endocrine system: balance and interplay in response to exercise training Dr N. Keay

Saturated fat does not clog the arteries: coronary heart disease is a chronic inflammatory condition, the risk of which can be effectively reduced from healthy lifestyle interventions British Journal of Sports Medicine 2017

Longitudinal Associations of Leptin and Adiponectin with Heart Rate Variability in Children Frontiers in Physiology 2017

A Proposal for a Study on Treatment Selection and Lifestyle Recommendations in Chronic Inflammatory Diseases: A Danish Multidisciplinary Collaboration on Prognostic Factors and Personalised Medicine Nutrients 2017

Assessment of Metabolic Flexibility by Means of Measuring Blood Lactate, Fat, and Carbohydrate Oxidation Responses to Exercise in Professional Endurance Athletes and Less-Fit Individuals Sports Medicine 2017

Skeletal muscle mitochondria as a target to prevent or treat type 2 diabetes mellitus Nature Reviews Endocrinology

Insulin and osteocalcin: further evidence for a mutual cross-talk Endocrine 2017

HbA1c levels, diabetes duration linked to fracture risk Endocrine Today 2017

The cellular and molecular bases of leptin and ghrelin resistance in obesity Nature Reviews Endocrinology 2017

Metabolic and Endocrine System Networks Dr N. Keay

Adiponectin and resistin: potential metabolic signals affecting hypothalamo-pituitary gonadal axis in females and males of different species Reproduction 2017

Optimal Health: For All Athletes! Part 4 – Mechanisms Dr N. Keay, British Association of Sport and Exercise Medicine 2017

Ubiquitous Microbiome: impact on health, sport performance and disease Dr N. Keay

The microbiome of professional athletes differs from that of more sedentary subjects in composition and particularly at the functional metabolic level Gut. BMJ

Interplay between gut microbiota, its metabolites and human metabolism: Dissecting cause from consequence Trends in Food Science & Technology 2016

Temporal considerations in Endocrine/Metabolic interactions Part 1 Dr N. Keay, British Journal of Sports Medicine 2017

Temporal considerations in Endocrine/Metabolic interactions Part 2 Dr N. Keay, British Journal of Sports Medicine 2017

Sleep Duration and Risk of Type 2 Diabetes Paediatrics 2017

Later circadian timing of food intake is associated with increased body fat Am J Clin Nutr. 2017

Effects of caloric intake timing on insulin resistance and hyperandrogenism in lean women with polycystic ovary syndrome Clin Sci (London)

Immunity around the clock Science

Effect of Time of Day on Performance, Hormonal and Metabolic Response during a 1000-M Cycling Time Trial PLOS

Type 2 diabetes mellitus and psychological stress — a modifiable risk factor Nature Reviews Endocrinology 2017

Recovery of ovarian activity in women with functional hypothalamic amenorrhea who were treated with cognitive behaviour therapy Fertil Steril