Lifestyle Choices

Slide1
Lifestyle Choices: Exercise, Nutrition, Sleep

Lifestyle factors of exercise, nutrition and sleep are vital for optimising health. In the illustration shown, ideally we should be in the green zone representing a balance between these lifestyle factors. Slipping into the peripheral red zone represents an imbalance: either too much or too little of any of these three elements. In particular exercise is of paramount importance being the most effective way of producing beneficial, multi-system effects mediated via the Endocrine system to optimise health and playing an important role in chronic disease prevention. However, it is not just a matter of what, but when: timing is crucial in integrating lifestyle factors with internal biological clocks. Beyond these guiding principles, personal preference and choice is emerging as being just as important as the lifestyle factor itself.

In a fascinating study, 58 participants were given either a prescribed exercise session, or a choice of exercise. Afterwards the participants were presented with a choice of foods, which they believed was simply as way of thank you for taking part in the exercise study. Post exercise, in those given no choice exercise, higher energy intake of food was consumed with larger proportion of “unhealthy” food compared to choice exercise group. The choice exercise group reported greater value and enjoyment of the exercise session. Thus autonomous choice of exercise not only provides positive reinforcement of exercising, but subsequent food choice is improved.

This concept of facilitating self determination, particularly when it comes to exercise was explored at the the recent annual British Association of Sport and Exercise conference. “Practicalities of intervention design, adherence and motivation” was presented by Dr Carly McKay from Bath University, who described how empowering people to make choices is far more likely to mean they will adhere to those lifestyle options that will optimise health.

What about the optimal timing of exercise which might improve motivation and performance? Well this depends on the context and what you are trying to achieve. In the case of training for competition and competition itself, optimal performance tends to be early evening, providing the most favourable hormonal milieu. Although in theory the morning diurnal release of cortisol might help with exercise, the downside is that this may interfere with blood glucose regulation. Furthermore, focusing on just one hormone in the Endocrine system, rather than the integrated function of the hypothalamic-pituitary axis could be misleading. Although due respect should be paid to internal biological clocks, to prevent circadian misalignment between internal pacemakers and external factors; equally becoming too obsessive about sticking to a rigid schedule would psychologically take away that essential element of choice. Practicality is a very important consideration and a degree of flexibility when planning the timing of exercise. For example, my choice of cardiovascualar exercise is swimming, which I fit in according to work commitments and when public lane swimming is available. Fortunately whilst at the BASEM conference in Bath, these practical conditions were met during the lunch break to take advantage of the 50m pool at Bath University. Pragmatic, not dogmatic when it comes to timing of exercise.

Timing of nutrition post exhaustive exercise is an important factor in supporting bone health. Immediate, rather than delayed refuelling with carbohydrate and protein is more advantageous in the balance of bone turnover markers; favouring formation over resorption. In the longer term, prolonged low energy availability as in the situation of relative energy deficiency in sport (RED-S) has a potentially irreversible adverse effect on bone health. In terms of the timing of meals, not eating too close to going to sleep, ideally 2 hours before melatonin release, is best for metabolic health.

Backing up the lifestyle choices of exercise and nutrition is sleep. Timing, duration and quality of sleep is essential for many aspects of health such as hormonal release of growth hormone, functional immunity and cognitive function. Certainly it is well recognised that shift workers, with circadian misalignment: disturbed sleep patterns relative to intrinsic biological clocks, are more at risk of developing cardio-metabolic disease.

In summary, a prescriptive approach to lifestyle factors could be counter productive. Discussing options and encouraging individuals to make their own informed and personal choices is far more likely to enable that person to take responsibility for their health and adhere to changes in lifestyle that are beneficial for their health. Having worked in hospital based NHS diabetic clinics for many years, I appreciate that supporting reluctant exercisers is not always an easy task. Equally it can be difficult to distinguish between the effects of ageing and loss of fitness. However, this does not mean that this supportive and inclusive approach should be abandoned. Rather, encouraging people to participate in decision making that they feel leads to options that are realistic and beneficial, is the approach most likely to work, especially in the long term.

“If we could give every individual the right amount of nourishment and exercise, not too little and not too much, we would have found the safest way to health.”
— Hippocrates

 

For more discussion on Health Hormones and Human Performance come to British Association of Sport and Exercise Medicine Spring Conference 

BAsem2018_SpringConf_BJSM

References

Presentations

One road to Rome: Exercise Dr N. Keay, British Journal of Sports Medicine 2017

Endocrine system: balance and interplay in response to exercise training Dr N. Keay 2017

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

Internal Biological Clocks and Sport Performance Dr N. Keay, British Association of Sport and Exercise Medicine 2017

Providing Choice in Exercise Influences Food Intake at the Subsequent Meal Medicine & Science in Sports & Exercise October 2017

BASEM/FSEM Annual Conference 2017, Assembly Rooms, Bath

Addiction to Exercise – what distinguishes a healthy level of commitment from exercise addiction? Dr N. Keay, British Journal of Sports Medicine 2017

The Effect of Postexercise Carbohydrate and Protein Ingestion on Bone Metabolism Translational Journal of the American College of Sports Medicine October 2107

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

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

Focus on physical activity can help avoid unnecessary social care British Medical Journal October 2017

Athletic Fatigue: Part 2

A degree of athletic fatigue following a training session, as described in part 1, is required to set in motion mechanisms to drive beneficial adaptations to exercise. At what point does this process of functional over-reaching tip into non-functional over-reaching denoted by failure to improve sports performance? Or further still along the spectrum and time scale, the chronic situation of overtraining and decrease in performance? Is this a matter of time scale, or degree, or both?

Slide1
Integrated Periodisation of Training Load, Nutrition and Recovery keeps an individual on the green plateau, avoiding descent into the red zone, due to an excess or deficiency

Determining the tipping point between these fatigue situations is important for health and performance. A first step is always to exclude underlying organic disease states, be these of Endocrine, systemic inflammatory or infective aetiologies. Thereafter the crucial step is to assess whether the periodisation of training, nutrition and recovery are integrated over a training block and in the longer term over a training season.

What about the application of Endocrine markers to monitor training load? Although the recent studies described below are more applicable to research scenarios, they give some interesting insights into the interactive networks effects of the Endocrine system and the multifactorial nature of fatigue amongst individual athletes.

In the short term, during a 2 day rowing competition, increases in wakening salivary cortisol were noted followed by return towards baseline in subsequent 2 day recovery. Despite individual variability with salivary cortisol measurement, this does at least offer a noninvasive way to adjust training loads around competition time for elite athletes.

Over an 11 day stimulated training camp and recovery during the sport specific preparatory phase of the training season, blood metabolic and Endocrine markers were measured. In the case of an endurance based training camp in cyclists, a significant increase in urea (due to protein breakdown associated with high energy demand training) and decrease in insulin-like growth factor 1 (IGF1) from baseline were noted. Whereas for the strength-based athletes for ball sports, an increase in creatine kinase (CK) was seen, as a result of muscle damage. This study demonstrates how different markers of fatigue are specific to sport discipline and mode of training. Large inter-individual variability existed between the degree of change in markers and degree of fatigue.

In the longer term, for the case of overtraining syndrome potential Endocrine markers have been reviewed. Whilst basal levels of most measured hormones remained stable, a blunted submaximal exercise response of growth hormone (GH), prolactin and ACTH could be indicative of developing overtraining syndrome. Whilst this review is interesting, dynamic testing is not a practical approach and these findings are not specific to over training. Rather this blunted dynamic exercise response would indicate relative suppression of the neuroendocrine hypothalamic-pituitary axis which could potentially involve other stressors such as inadequate sleep or poor nutrition. Although basal levels may lie “within the normal range”, if both pituitary derived stimulating hormone and end endocrine gland hormone concentrations fall in the lower end of the normal ranges (eg low end of range TSH and T4) this is consistent with mild hypothalamic suppression observed over the range of training and fatigue conditions (functional/non-functional and overtraining) and/or Relative Energy Deficiency in Sports (RED-S).

Although the studies above are of research interest, non invasive monitoring, specific to an athlete is more practical for monitoring the effects of training. Several useful easily measurable metrics can give clues: resting heart rate, heart rate variability, power output. Tools on Strava and Training Peaks provide practical insights in monitoring training effectiveness via these metrics. A range of mobile apps makes it ever easier to augment a personal training log to include these training metrics, along with feel, sleep and nutrition. Such a log provides feedback on health and fitness for the individual athlete, in order to personalise training plans. Certainly adding the results from any standard basal blood tests will also help add to the picture, along the lines of building a longitudinal personal biological passport. After all, “normal ranges” are based on the general population, of which top level athletes may represent a subgroup. The more personalised the metics recorded over a long time scale, the more sensitive and useful the process to guide improvement in sport performance.

Context is key when considering athletic fatigue: temporal considerations and individual variation. Certainly the interactive network effects of the Endocrine system are important in determining the degree of adaptation to exercise and therefore sports performance. However the Endocrine system acts in conjunction with many other systems (metabolic, immune and inflammatory), in determining the effectiveness of training in improving sports performance. So it is not surprising that one metric or marker in isolation is not predictive of fatigue status in individual athletes.

For more discussion on Health, Hormones and Human Performance come to the British Association of Sport and Exercise Medicine annual conference

Presentations

References

Athletic Fatigue: Part 1

Endocrine system: balance and interplay in response to exercise training

Temporal considerations in Endocrine/Metabolic interactions Part 1

Fatigue, sport performance and hormones..more on the endocrine system Dr N Keay, British Journal of Sports Medicine 2017

Sport Performance and RED-S, insights from recent Annual Sport and Exercise Medicine and Innovations in Sport and Exercise Nutrition Conferences Dr N Keay, British Journal of Sports Medicine 2017

Capturing effort and recovery: reactive and recuperative cortisol responses to competition in well-trained rowers British Journal of Sports Medicine

Blood-Borne Markers of Fatigue in Competitive Athletes – Results from Simulated Training Camps Plos One

Hormonal aspects of overtraining syndrome: a systematic review BMC Sports Science, Medicine and Rehabilitation 2017

Clusters of Athletes – A follow on from RED-S blog series to put forward impact of RED-S on athlete underperformance Dr N Keay, British Association of Sport and Exercise Medicine 2017

Strava Fitness and Freshness Science4Performance 2017

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

Sports Endocrinology – what does it have to do with performance? Dr N Keay, British Journal of Sports Medicine 2017

Athletic Fatigue: Part 1

Interpreting athletic fatigue is not easy. Consideration has to be given to context and time scale. What are the markers and metrics that can help identify where an athlete lies in the optimal balance between training, recovery and nutrition which support beneficial adaptations to exercise whilst avoiding the pitfalls of fatigue and maladaptation? This blog will discuss the mechanisms of athletic fatigue in the short term.

Screen Shot 2017-08-30 at 09.17.58
Proposed causes of fatigue dependent on duration and intensity of training session

In the short term, during an endurance training session or race, the temporal sequence of athletic fatigue depends on duration and intensity. It is proposed that below lactate threshold (LT1), a central mechanism governs: increasing central motor drive is required to maintain skeletal muscular power output until neuromuscular fatigue cannot be overcome. From lactate threshold (LT1) to lactate turn point (LT2), a combination of central and peripheral factors (such as glycogen depletion) are thought to underpin fatigue. During high intensity efforts, above LT2 (which correspond to efforts at critical power), accumulation of peripheral metabolites and inability to restore homeostasis predominate in causing fatigue and ultimately inability to continue, leading to “task failure”. Of course there is a continuum and interaction of the mechanisms determining this power-duration relationship. As glycogen stores deplete this impacts muscle contractility by impairing release of calcium from the sarcoplasmic reticulum in skeletal muscle. Accumulation of metabolites could stimulate inhibitory afferent feedback to central motor drive for muscle contraction, combined with decrease in blood glucose impacting central nervous system (CNS) function.

Even if you are a keen athlete, it may not be possible to perform a lactate tolerance or VO2 max test under lab conditions. However a range of metrics, such as heart rate and power output, can be readily collected using personalised monitoring devices and then analysed. These metrics are related to physiological markers. For example heart rate and power output are surrogate markers of plasma lactate concentration and thus can be used to determine training zones.

A training session needs to provoke a degree of training stress, reflected by some short term fatigue, to set in motion adaptations to exercise. At a cellular level this includes oxidative stress and exerkines released by exercising tissues, backed up by Endocrine responses that continue to take effect after completing training during recovery and sleep. Repeated bouts of exercise training, followed by adequate recovery, result in a stepwise increase in fitness. Adequate periodised nutrition to match variations in demand from training also need to be factored in to prevent the Endocrine system dysfunction seen in Relative Energy Deficiency in Sports (RED-S), which impairs Endocrine response to training and sports performance. Integrated periodisation of training/recovery/nutrition is essential to support beneficial multi-system adaptations to exercise on a day to day time scale, over successive training blocks and encompassing the whole training and competition season. Psychological aspects cannot be underestimated. At what point does motivation become obsession?

In Part 2 the causes of athletic fatigue over a longer time scale will be discussed, from training blocks to encompassing whole season.

For more discussion on Health, Hormones and Human Performance come to the British Association of Sport and Exercise Medicine annual conference

Presentations

References

Endocrine system: balance and interplay in response to exercise training

Power–duration relationship: Physiology, fatigue, and the limits of human performance European Journal of Sport Science 2016

Strava Ride Statistics Science4Performance 2017

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

Relative Energy Deficiency in Sports (RED-S) Practical Considerations for Endurance Athletes

Sports Endocrinology – what does it have to do with performance? Dr N Keay, British Journal of Sports Medicine 2017

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

Addiction to Exercise – what distinguishes a healthy level of commitment from exercise addiction? Dr N Keay, British Journal of Sports Medicine 2017

 

 

Hormones and Sports Performance

WADA

The interactive network effects of the Endocrine system are key in producing effective adaptations to exercise. This in turn results in improved sport performance. Athletes are aware of the crucial role of the Endocrine system in sports performance. Therefore it is not surprising that, on the World Anti-Doping agency (WADA) banned list, the majority of prohibited substances both in and out of competition are hormones, mimetics and hormone and metabolic modulators. In 2013 hormones accounted for 75% of all adverse analytical findings. Use of such substances to enhance performance is not only illegal and against the spirit of sport, but also potentially harmful to the health of the athlete.

Considering some of these prohibited hormones, the usual suspects start with anabolic agents: anabolic androgenic steroids whether these be synthetic derivatives taken exogenously or molecular identical endogenous steroids, including metabolites and isomers, administered exogenously.  In a study recently published in the BJSM, female athletes with free testosterone levels in the highest tertile displayed better performance than those in lowest tertile of up to 4.5% in certain power/anaerobic events such as 400m, 800m, hammer and pole jump. This may be due to associated body composition with increased lean mass and “risk taking” behaviour. In 2015, the Court of Arbitration for Sport ruled that the IAAF should suspend the existing upper limit on female athlete testosterone, of 10nmol/l, because at the time there was insufficient evidence that such levels would improve performance in female athletes. In view of the results of this study, the situation may have to be reviewed. This is clearly an ethical dilemma regarding intersex athletes, whose hyerandrogenism is due to endogenous biological factors.

Next up there are peptide hormones/growth factors/mimetics. As previously discussed, growth hormone (GH) proved a challenging peptide hormone for which to develop a dope test. Firstly what are the “normal” ranges for elites athletes, seeing as exercise and sleep are the two major stimuli for GH release? Furthermore, elite athletes represent a subset of the population, for whom the normal range may differ. Secondly exogenous genetically engineered GH is to all intents and purposes identical to endogenous secreted GH, with a relatively short half life. Hence early on in development of a dope test we realised that downstream markers, particularly of bone turnover would have to be used. This brings the discussion to erythropoietin (EPO). In a similar way to GH and allied releasing factors, increases in key surrogate variables producing performance enhancement are measured. In the case of exogenous EPO these are changes in haemoglobin and haematocrit as recorded in an athletes’ biological passport. A recent study on amateur cyclists given EPO in a double blind randomised placebo controlled trial, reported no improvement in a submaximal field test. Although the effects in elite cyclists would arguably be more relevant, this is not possible for obvious ethical reasons. Nevertheless the effects on elite cyclists during maximal efforts, for example in an attack on a mountainous stage in the Tour de France, would not necessarily correlate to amateurs in submaximal conditions, where there may be other limiting factors to performance. In addition athletes may use supraphysiological dosing regimens (“stacking” or “pyramiding”), not necessarily comparable to those used in clinical studies. In my opinion, apart from potential ergogenic benefits, whatever the degree, the intention to “take a short cut” to improve performance is the issue, not to mention the adverse health sequelae, for example, the study noted a thrombotic tendency with EPO, even in modest doses.

Hormone and metabolic modulators have received attention following the fall from grace of Maria Sharapova. Meldonium which is licensed for use in Baltic countries has beneficial anti-ischaemic effects in cardiovascular, neurological and metabolic disease states. Apparently this drug was use amongst Soviet troops during the war in mountainous Afghanistan. Amongst athletes the intended purpose is to improve endurance exercise performance and recovery post exercise. This is an example where an unfortunate spin off from developing drugs to treat disease states, is that such drugs are also see by some athletes as a short cut to enhance sport performance.

Although thyroxine is not on the banned list, there are certainly arguments that exogenous thyroxine should not be given to athletes, unless there is definitive biochemical evidence that the athlete suffers with hypothyroidism: as defined by criteria for diagnosing this condition with consistently elevated thyroid stimulating hormone (TSH) above the normal range, with paired low T4. Thyroid autoantibodies may also provide extra clinical information. The effect of intense training on the hypothalamic-pituitary-thyroid axis is to slightly suppress both TSH and T4, whilst these remain in the normal range. In this instance medicating with exogenous thyroxine would be to support recovery from training, rather than to legitimately treat a proven medical condition. In a similar way a TUE is only justified for testosterone in pathological disorders of the hypothalamo-pituitary-testicular axis and not for suppressed testosterone as a result of training stress.

Unfortunately supplements are a source of preventable anti-doping rule violations (ADRV) representing up to half of the total ADRVs. Either such supplements have not listed all the contents, or contamination has occurred during manufacture. If an athlete wishes to take supplements, certainly it is advisable only to take reliably tested products. Nevertheless even if an athlete unintentionally ingests prohibited substances, then ultimately they are still liable. If claims of the benefits of such supplements sound too good to be true, they probably are. Ultimately supplements will not win races and there is no substitute for periodised training, nutrition and recovery.

Effectively there is an arms race between would-be doper and medical expertise in Sports Endocrinology. However, freezing samples for potential re-analysis with emerging understanding and technology in the future is an added deterrent for athletes whose intention is to take a short cut to improving sport performance.

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

Endocrine system: balance and interplay in response to exercise training

Sports Endocrinology – what does it have to do with performance? Dr N. Keay, British Journal of Sports Medicine 2017

Enhancing Sport Performance: Part 1 Dr N. Keay, British Association of Sport and Exercise Medicine 2017

Keay N, Logobardi S, Ehrnborg C, Cittadini A, Rosen T, Healy ML, Dall R, Bassett E, Pentecost C, Powrie J, Boroujerdi M, Jorgensen JOL, Sacca L. Growth hormone (GH) effects on bone and collagen turnover in healthy adults and its potential as a marker of GH abuse in sport: a double blind, placebo controlled study. Journal of Clinical Endocrinology and Metabolism. 85 (4) 1505-1512. 2000.

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

Enabling Sport Performance: part 2

Enhancing Sports Performance: part 3

World Anti-Doping Agency

Serum androgen levels and their relation to performance in track and field: mass spectrometry results from 2127 observations in male and female elite athletes British Journal of Sports Medicine

Doping Status of DHEA Treatment for Female Athletes with Adrenal Insufficiency Clinical Journal of Sports Medicine 2017

Testosterone treatment and risk of venous thromboembolism: population based case-control study British Medical Journal 2016

Effects of erythropoietin on cycling performance of well trained cyclists: a double-blind, randomised, placebo-controlled trial The Lancet, Haematology 2017

Meldonium use by athletes at the Baku 2015 European Games. Adding data to Ms Maria Sharapova’s failed drug test case British Journal of Sports Medicine 2016

Fatigue, sport performance and hormones..more on the endocrine system  Dr N. Keay, British Journal of Sports Medicine 2017

Australian Sport Anti-Doping Authority

 

Addiction to Exercise

ExerciseAddiction

Health is not just the absence of illness, but rather the optimisation of all components of health: physical, mental and social. Exercise has numerous benefits on all these aspects. However, a recent article in the British Medical Journal described how exercise addiction can have detrimental physical, mental and social effects.

Dedication and determination are valuable qualities required to be successful in life, including achieving sporting prowess. Yet, there is a fine line between dedication and addiction.

To improve sports performance, cumulative training load has to be increased in a quantified fashion, to produce an overload and hence the desired physiological and Endocrine adaptive responses. Integrated periodisation of training, recovery and nutrition is required to ensure effective adaptation. Sufficient energy availability and quality of nutrition are essential to support health and desired adaptations. On the graph above the solid blue line represents a situation of energy balance, where the demands of increased training load are matched by a corresponding rise in energy availability. This can be challenging in sports where low body weight confers a performance or aesthetic advantage, where the risk of developing relative energy deficiency in sport (RED-S) has implications for Endocrine dysfunction, impacting all aspects of health and sports performance.

Among those participating in high volumes of exercise, what distinguishes a healthy level of commitment from exercise addiction? Physical factors alone are insufficient: all those engaging in high levels of training can experience overuse injuries and disruption in Endocrine, metabolic and immune systems. Equally, in all these exercising individuals, overtraining can result in underperformance.

Psychological factors are the key distinguishing features between the motivated athlete and the exercise addict. In exercise addiction unhealthy motivators and emotional connection to exercise can be identified as risk factors. In exercise addiction the motivation to exercise is driven by the obsession to comply with an exercise schedule, above all else. This can result in negative effects and conflict in social interactions, as well as negative emotional manifestations, such as anxiety and irritability if unable to exercise, including the perceived necessity to exercise even if fatigued or injured.

Two categories of exercise addiction have been described. Primary exercise addiction is the compulsion to follow an excessive training schedule. Without balancing energy intake, the physical consequence may be a relative energy deficiency, as indicated on the graph by the dashed blue line. In secondary exercise addiction, the situation is compounded by a desire specifically to control body weight. These individuals consciously limit energy intake, almost inevitably developing the full clinical syndrome described in RED-S, dragging them down to the position indicated by the dotted blue line on the chart. These situations of exercise addiction can lead to varying risk categories of RED-S.

As described at the start of this blog, there is a blurred boundary between the dedicated athlete and the exercise addict. In practice there is most likely a cross over. For example, an athlete may start with healthy motivators and positive emotional connection to exercise, which can become a primary addiction to adhere rigidly to a training schedule, rather than putting the emphasis on the outcome of such training. In the case of an athlete where low body weight is an advantage, it is easy to appreciate how this could become a secondary exercise addiction, where the motivation for exercising becomes more driven by the desire to control weight, rather than performance.

In order to support those with exercise addiction, discussion needs to focus on adopting a more flexible approach to exercise, by recognising that exercise addiction has detrimental effects on all aspects of current and long term health. Furthermore, in the case of athletes, a multi-disciplinary approach is desirable to help the individual refocus on the primary objective of training: to improve performance. In all situations, discussion should explore modifications to exercise and nutrition, in order to prevent the negative effects of RED-S on health and performance.

Exercise has numerous health benefits and is usually viewed as positive behaviour. However, the outcome of exercise is related to the amount of training, appropriate nutrition and motivation for exercising.

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

Addiction to Exercise British Medical Journal 2017

Clusters of Athletes British Association of Sport and Exercise Medicine 2017

Sport performance and relative energy deficiency in sport British Journal of Sport Medicine 2017

Balance of recovery and adaptation for sports performance British Association of Sport and Exercise Medicine 2017

Optimal Health for all athletes Part 4 Mechanisms of RED-S British Journal of Sport Medicine 2017

Sports Endocrinology – what does it have to do with performance? British Journal of Sport Medicine 2017

Inflammation: Why and How Much? British Association of Sport and Exercise Medicine 2017

Fatigue, Sport Performance and Hormones…

How do you feel on Monday morning, when the alarm wakes you at 7am with a day of work ahead after the weekend? A bit tired, slightly lethargic, sluggish, maybe a little bit down, perhaps a few regrets about somewhat too much alcohol/food over weekend, frustrated that the exercise training schedule didn’t go according to plan?sleep

There are many causes of fatigue and sport underperformance: Endocrine, immunological, infective, metabolic, haematological, nutritional, digestive, neoplastic….. The adrenal gland in the Endocrine system in particular has come in for some bad press recently.

Adrenal woes

Undoubtedly the adrenal glands have a case to answer. Situated above the kidneys these Endocrine glands produce glucocorticoids, mineralocorticoids, androgens from the adrenal cortex and from the adrenal medulla adrenaline. Glucocorticoids (e.g. cortisol) have a metabolic function to maintain energy homeostasis and an immune function to suppress inflammation. Mineralocorticoids (e.g. aldosterone) maintain electrolyte and water balance. As mineralocorticoids and glucocorticoids are similar biological steroid molecules, there is some degree of overlap in their actions.

Addison’s disease and Cushing’s disease are serious medical conditions, corresponding respectively to under or over production by the adrenal glands of steroid hormones. Someone presenting in Addisonian crisis is a medical emergency requiring resuscitation with intravenous hydrocortisone and fluids. Conversely those with Cushing’s can present with hypertension and elevated blood glucose. Yet, apart from in the extremes of these disease states, cortisol metrics do not correlate with clinical symptoms. This is one reason why it is unwise and potentially dangerous to stimulate cortisol production based on clinical symptoms. Inappropriate exogenous steroid intake can suppress normal endogenous production and reduce the ability to respond normally to “stress” situations, such as infection. This is why the prescription of steroids, for example to reduce inflammation in autoimmune disease, is always given in a course of reducing dose and a steroid alert card has to be carried. Athletes should also be aware that exogenous steroid intake is a doping offence.

However, what is the “normal” concentration for cortisol? Well, for a start, it depends what time of day a sample is taken, as cortisol is produced in a circadian rhythm, with highest values in the morning on waking and lowest levels about 2/3am. Nor is this temporal periodicity of production the only variable, there are considerations such as tissue responsiveness and metabolism (break down) of the hormone. On top of these variables there are other inputs to the feedback control mechanism, which can in turn influence these variables. In other words, focusing on the steroid hormone production of the adrenal gland in isolation, could overlook underlying hypothamalmic-pituitary-adrenal (H-P-A) axis dysfunction and indeed wider issues.

Much maligned thyroid

That is not end of the possible causes of fatigue and sport underperformance: the H-P-A axis is just one of many interrelated, interacting Endocrine systems. There are many neuroendocrine inputs to the hypothalamus, the gate keeper of the control of the Endocrine system. Furthermore there are network interaction effects between the various Endocrine control feedback loops. For example cortisol towards the top end of “normal” range can impede the conversion at the tissue level of thyroxine (T4) to the more active triiodothyronine (T3) by enzymes which require selenium to function. Rather T4 can be converted to reverse T3 which is biologically inactive, but blocks the receptors for T3 and thus impair its action. This in turn can interfere with the feedback loop controlling thyroid function (hypothalamic-pituitary-thyroid axis). The physiological ratio of T4 to T3 is 14:1, which is why supplementation with desiccated thyroid is not advisable with ratio of 4:1. There are other processes which can crucially interfere with this peripheral conversion of T4 to T3, such as inflammation and gut dysbiosis, which can occur as result of strenuous exercise training. So what might appear to be a primary thyroid dysfunction can have an apparently unrelated underlying cause. Indeed amongst highly trained athletes thyroid function can show an unusual pattern, with both thyroid stimulating hormone (TSH) and T4 at low end of the “normal “range, thought to be due to resetting of the hypothalamic-pituitary control signalling system. This highlights that the “normal” range for many hormones comprises subsets of the population and in the case of TSH, the “normal” range is not age adjusted, despite TSH increasing with age. As described by Dr Boelaert at recent conferences, there is certainly no medical justification for reports of some athletes in the USA being given thyroxine with TSH>2 (when the normal range is 0.5-5mU/l). Although thyroxine is not on the banned list for athletes, it could have potentially serious implications for health due to its impact on the Endocrine system as a whole.

Endocrine system interactions

SportsEndocrinologyWordCloud

Symptoms of fatigue are common to many clinical conditions, not just dysfunction in an Endocrine control axis in isolation, nor even the network interactive effects of the Endocrine system in isolation. For example, the impact of nutrition relative to training load produces a spectrum of clinical pictures and Endocrine disturbances seen in Relative Energy Deficiency in Sport (RED-S) in terms of health and sport performance.

Underlying mechanisms of Endocrine dysfunction

There may be predisposing factors in developing any clinical syndrome, the usual suspects being inflammation: whether infective, dysbioses, autoimmune; nutritional status linked with endocrine status;  training load with inadequate periodised recovery to name a few….

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

From population based norms to personalised medicine: Health, Fitness, Sports Performance British Journal of Sport Medicine 2017

Sports Endocrinology – what does it have to do with performance? British Journal of Sport Medicine 2017

Advanced Medicine Conference, Royal College of Physicians, London 13-16 February 2017, Endocrine session: Dr Kristien Boelaert, Dr Helen Simpson, Professor Rebecca Reynolds

Subclinical hypothydroidism in athletes. Lecture by Dr Kristeien Boelaert, British Association of Sport and Exercise Medicine Spring Conference 2014. The Fatigued Athlete

Sport Performance and RED-S, insights from recent Annual Sport and Exercise Medicine and Innovations in Sport and Exercise Nutrition Conferences British Journal of Sport Medicine 2017

Relative Energy Deficiency in Sport CPD module British Association of Sport and Exercise Medicine 2017

Sleep for health and sports performance British Journal of Sport Medicine 2017

Inflammation: why and how much? British Association of Sport and Exercise Medicine 2017

Clusters of athletes British Association of Sport and Exercise Medicine 2017

Enhancing Sport Performance: Part 1 British Association of Sport and Exercise Medicine 2017

Balance of recovery and adaptation for sports performance British Association of Sport and Exercise Medicine 2017

Annual Sport and Exercise Medicine Conference, London 8/3/17 Gut Dysbiosis, Dr Ese Stacey

Adrenal fatigue does not exist: a systematic review BMC Endocrine Disorders. 2016; 16(1): 48.

A Controversy Continues: Combination Treatment for Hypothyroidism Endocrine News, Endocrine Society April 2017