Optimal health: including female athletes! Part 1 Bones

webmd_rm_photo_of_porous_bonesIt is hard to dispute that women are underrepresented in medical research and certainly there are not many studies that include female athletes. Does this matter? After all whatever your gender the same physiological and metabolic processes occur. However the Endocrine system is where there are distinct differences in sex steroid production, which in turn have different responses in multiple target cells.

Although studies on changes in exercise performance in response to various dietary interventions and training regimes are often very interesting and well described, I am left feeling slightly uneasy when the subjects are all males. The cause for my concern is that the female hypothalamus-pituitary-ovarian axis is a particularly sensitive system with complex feedback loops and interacting networks.

Menstrual disturbance is not unusual amongst women in sport/dance where low body weight is an advantage. When a ballet dancer performs pointe work, putting full body weight through the big toe is hard enough, without extra load! Some women might consider it a convenience to be spared the hassle of menstruation. At age 24, I was perfectly fine never having had a period (primary amenorrhoea), or so I thought, being no more tired than other hospital medical colleagues working full time, studying for postgraduate medical exams and also involved in exercise training.

While working as a SHO at Northwick Park Hospital, I volunteered to be included in a study at the British Olympic Medical Association. The study was of female lightweight rowers and ballet dancers to look at VO2 max, percentage body fat and bone mineral density (BMD). I had been doing Ballet intensively (and obsessively) from a very young age, together with restricted fat and carbohydrate intake. Sounds a familiar scenario? Although I looked perfectly healthy (and I did not fit into a clinical condition requiring treatment), worked and danced well, my bone density was worryingly low. So if you are a female doing weight-bearing exercise or resistance training which loads the skeleton, these activities promoting osteogenesis will be negated if you are not ovulating and producing adequate oestrogens. The female athlete triad composed of disordered eating, amenorrhoea and low BMD was originally described by Drinkwater in 1984. However, once pathological states causing amenorrhoea have been excluded, in medical terms the female athlete triad did not necessarily constitute a disease state requiring intervention, rather subset of the “normal population”.

How significant is having low BMD compared to the age-matched population during your 20s? Could this even be viewed as a reversible adaptation to training, reflected in site specific differences in BMD according to sport? After all, when female athletes retire with decreased training “stress” and more “relaxed” diet, menses often resume and therefore does BMD also improve? This was the question I sought to answer in my study on 57 premenopausal retired professional dancers. Even with return of menses, if these athletes had experienced previous amenorrhoea of more than 6 month duration, then bone loss was irrecoverable. Current low BMD was also correlated to lowest body weight (independent of amenorrhoea) during dance career and later age of menarche. There did not appear to be any protective effect of being on the oral contraceptive pill. Constructing a model of BMD using multiple regression 33.6% of total variation in z (age matched) score for BMD at lumbar spine was accounted for by duration of amenorrhea, age at menarche and lowest body weight during dance career. So “athletic” hypothalamic amenorrhea rather than being a reversible, adaptive response has long term, irreversible effects on BMD.

Apart from bone metabolism, what other systems are impacted by mismatch of energy intake and expenditure in overtly healthy athletes? Are the endocrine and metabolic systems in male athletes also affected by subtle imbalances in training energy expenditure and dietary intake? What about young athletes? In my next blog I will explore the rationale behind the original female athlete triad now being described as part of Relative Energy Deficiency in sports (RED-S). The implications for current health and sports performance, as well as long term health in both adult men and women and young athletes.

For further discussion on Endocrine and Metabolic aspects of SEM come to the BASEM annual conference 22/3/18: Health, Hormones and Human Performance

References

Keay N, Fogelman I, Blake G. Bone mineral density in professional female dancers. British Journal of Sports Medicine, vol 31 no2, 143-7, June 1997.

Keay N. Bone mineral density in professional female dancers. IOC World Congress on Sports Sciences. October 1997.

Keay N, Bone Mineral Density in Professional Female Dancers, Journal of Endocrinology, November 1996, volume 151, supplement p5.

Keay N, Bone Mineral Density in Female Dancers, abstract Clinical Science, Volume 91, no1, July 1996, 20p.

Keay N, Dancers, Periods and Osteoporosis, Dancing Times, September 1995, 1187-1189

Keay N, A study of Dancers, Periods and Osteoporosis, Dance Gazette, Issue 3, 1996, 47

Fit to Dance? Report of National inquiry into dancers’ health

Fit but fragile. National Osteoporosis Society

Your body your risk. Dance UK

From population based norms to personalised medicine: Health, Fitness, Sports Performance British Journal of Sport Medicine 22/2/17

Optimal Health: Including Male Athletes! Part 2 – REDs Dr N. Keay, British Association Sport and Exercise Medicine

Optimal health: especially young athletes! Part 3 Consequences of Relative Energy Deficiency in sports Dr N. Keay, British Association Sport and Exercise Medicine

Optimal health: for all athletes! Part 4 Mechanisms Dr N. Keay, British Association Sport and Exercise Medicine

Sleep for Health and Sports Performance

“Sleep.. chief nourisher in life’s feast,” Macbeth.

In my blog for British Association of Sport and Exercise Medicine, I described improving sport performance by balancing the adaptive changes induced by training together with the recovery strategies to facilitate this, both in the short and long term.  alec0120-12x17

A recovery strategy which is vital in supporting both health and sport performance, during all stages of the training cycle is sleep.

Sufficient sleep is especially important in young athletes for growth and development and in order to support adaptive changes stimulated by training and to prevent injury. Amongst teenage athletes, studies have shown that a lack of sleep is associated with higher incidence of injury. This may be partly due to impaired proprioception associated with reduced sleep. Sleep is vital for consolidating neurological function and protein synthesis, for example in skeletal muscle. Sleep and exercise are both stimuli for growth hormone release from the anterior pituitary, which mediates some of these adaptive effects.

Lack of sleep can also interfere with functioning of the immune system due to disruption of the circadian rhythm of secretion in key areas of the Endocrine system. Athletes in heavy training, with high “stress” loads and associated elevated cortisol can also experience functional immunosuppression. So a combination of high training load and insufficient sleep can compound to disrupt efficient functioning of the immune system and render athletes more susceptible to illness and so inability to train, adapt and recover effectively.  Lack of sleep disrupts carbohydrate metabolism and recently found to suppress expression of genes regulating cholesterol transport. In overreaching training, lack of sleep could be either a cause or a symptom of insufficient recovery. Certainly sleep deprivation impairs exercise performance capacity (especially aerobic exercise) although whether this is due to a psychological, physical or combination effect is not certain.

Sufficient sleep quality and quantity is required for cognitive function, motor learning, and memory consolidation. All skills that are important for sports performance, especially in young people where there is greater degree of neuroplasticity with potential to develop neuromuscular skills. In a fascinating recorded lecture delivered by Professor Jim Horne at the Royal Society of Medicine, the effects of prolonged wakefulness were described. Apart from slowing reaction time, the executive function of the prefrontal cortex involved in critical decision making is impaired. Important consequences not only for athletes, but for doctors, especially for those of us familiar with the on call system in hospitals back in the bad old days. Sleep pattern pre and post concussive events in teenage athletes is found to be related to degree and duration of concussive symptoms post injury. The explanation of how sleep deprivation can cause these functional effects on the brain has been suggested in a study where subtle changes in cerebral neuronal structural properties were recorded. It is not known whether these changes have long term effects.

So given that sleep is essential not only for health and fitness, but to support sports performance, what strategies to maximise this vital recovery process? Use of electronic devices shortly before bedtime suppresses secretion of melatonin (neurotransmitter and hormone), which is a situation not conducive for sleep. Tryptophan is an amino acid precursor in the synthesis of melatonin and serotonin (neurotransmitter) both of which promote sleep. Recent research demonstrates that protein intake before bed can support skeletal and muscle adaptation from exercise and also recovery from tendon injury. Conversely there is recent report that low levels of serotonin synthesis may contribute to the pathogenesis of autoimmune inflammatory disease such as rheumatoid arthritis. This highlights the subtle balance between degree of change required for positive adaptation and a negative over-response, as in inflammatory conditions. This balance is different for each individual, depending on the clinical setting. So maybe time to revisit the warm milky drink before bed? Like any recovery strategy, sleep can also be periodised to support exercise training, with well structured napping during the day as described by Dr Hannah Macleod, member of gold winning Olympic Hockey team.

In conclusion, when you are planning your training cycle, don’t forget that periodised recovery to compliment your schedule should be factored in, with sleep a priority recovery and adaptation strategy.

For further discussion on Endocrine and Metabolic aspects of SEM come to the BASEM annual conference 22/3/18: Health, Hormones and Human Performance

References

Balance of recovery and adaptation for sports performance Dr N. Keay, British Association of Sport and Exercise Medicine

Sleep, Injury and Performance

Keay N. The effects of growth hormone misuse/abuse. Use and abuse of hormonal agents: Sport 1999. Vol 7, no 3, 11-12.

Wallace J, Cuneo R, Keay N, Sonksen P. Responses of markers of bone and collagen turover to exercise, growth hormone (GH) administration and GH withdrawal in trained adult males. Journal of Endocrinology and Metabolism 2000. 85 (1): 124-33.

Sleep and sporting performance

Young people: neuromuscular skills for sports performance

Prolonged sleep restriction induces changes in pathways involved in cholesterol metabolism and inflammatory responses

“Sleepiness and critical decision making”. Recorded lecture Professor Jim Horne, Royal Society of Medicine 16/11/16

What Does Sleep Deprivation Actually Do To The Brain?

Pre-Sleep Protein Ingestion to Improve the Skeletal Muscle Adaptive Response to Exercise Training

Exercise and fitness in young people – what factors contribute to long term health? Dr N. Keay, British Journal of Sports Medicine

Serotonin Synthesis Enzyme Lack Linked With Rheumatoid Arthritis

“Science in Elite Sport” Dr Hannah Macleod, University of Roehampton, 6/12/16

Young people: Neuromuscular skills for Sport Performance

Many publications report concerns over low exercise levels in young people. At the other end of the spectrum there are potential pitfalls to be avoided for young athletes. Some aspects have been discussed in my previous articles: Exercise and fitness in young people – what factors contribute to long term health? and Optimising Health, Fitness and Sports Performance for young people, below are some updates.

windsurf

Supporting previous publications that exercise in young people improves cognitive and academic performance, it was found that in boys delay in reading skills was associated with high levels of sedentary time combined with low levels of exercise. Low muscle tone, associated with lack of exercise is also proposed as potential inhibitor of learning in children. Lack of physical activity, coupled with unfavourable body composition in young people is linked with adverse outcomes for bone development and cardio-metabolic disease in adults. Now there also appears to be long term consequences for cognitive ability and neuromuscular skills.

For young people already involved in sport training, the same principles apply in that this represents the optimal time in life for development of not only physical fitness such as CV fitness, muscular strength and endurance, but also neuromuscular skills. All these factors are important to enhance sport performance and to avoid injury. The risk of injury is more prevalent in early sport specialisation, so any strategies to minimise injury risk is important. For example, periodised strength and conditioning with neuromuscular training to reinforce the acquisition of a diverse range of motor skills. In other words to combine both health related physical fitness (eg. CV fitness) with skill related fitness (eg. co-ordination). The Pilates style body conditioning which I teach for young people, includes developing flexibility, proprioception, core stability, balance and co-ordination which are applicable for all sports.

Collaboration with coaches, sports clubs, physiotherapists and other health care professionals is required to support young people and their families in optimising health and fitness.

For further discussion on Endocrine and Metabolic aspects of SEM come to the BASEM annual conference 22/3/18: Health, Hormones and Human Performance

References

Optimising Health, Fitness and Sports Performance for young people Dr N. Keay, British Journal of Sports Medicine

Exercise and fitness in young people – what factors contribute to long term health? Dr N. Keay, British Journal of Sports Medicine

Factors impacting bone development

Reading skills in sedentary boys

Muscle tone and leaning in children

Factors impacting bone development

Optimal Heath especially for Young athletes! British Association of Sport and Exercise Medicine

When to initiate integrative neuromuscular training to reduce sports-related injuries and enhance health in youth?

Sports Specialization, Part II: Alternative Solutions to Early Sport Specialization in Youth Athletes

The role of Pilates in facilitating sports performance

Optimising Health, Fitness and Sports Performance for young people

Version 2Young people need information in order to make life decisions on their health, fitness and sport training with the support of their families, teachers and coaches.

As discussed in my previous blog anima sana in corpore sano, exercise has a positive effect on all aspects of health: physical, mental and social. The beneficial impact of exercise is particularly important during adolescence where bodies and minds are changing. This time period presents a window of opportunity for young people to optimise health and fitness, both in the short term and long term.

The physical benefits of exercise for young people include development of peak bone mass, body composition and enhanced cardio-metabolic health. Exercise in young people has also been shown to support cognitive ability and psychological wellbeing.

Optimising health and all aspects of fitness in young athletes is especially important in order to train and compete successfully. During this phase of growth and development, any imbalances in training, combined with changes in proportions and unfused growth plates can render young athletes more susceptible to overuse injuries. A training strategy for injury prevention in this age group includes development of neuromuscular skills when neuroplasticity is available. Pilates is an excellent form of exercise to support sport performance.

In athletes where low body weight is an advantage for aesthetic reasons or where this confers a competitive advantage, this can lead to relative energy deficiency in sport (RED-S). Previously known as the female athlete triad, this was renamed as male athletes can also be effected. The consequences of this relative energy deficiency state are negative effects on metabolic rate, menstrual function, bone health, protein synthesis and immunity. If this situation arises in young athletes, then this is of concern for current health and may have consequences for health moving into adulthood.

A well informed young person can make decisions to optimise health, fitness and sports performance.

Link to Workshops

For further discussion on Endocrine and Metabolic aspects of SEM come to the BASEM annual conference 22/3/18: Health, Hormones and Human Performance

References

Optimal Health: Especially Young Athletes! Part 3 – Consequences of Relative Energy Deficiency in Sports Dr N. Keay, British Association Sport and Exercise Medicine 13/4/17

Report from Chief Medical Officer

Cognitive benefits of exercise

Injuries in young athletes

Young people: neuromuscular skills for sports performance

IOC consensus statement\

Exercise and fitness in young people – what factors contribute to long term health? Dr N. Keay, British Journal of Sports Medicine