Adrenal Function and Physical Performance - Cambridge Nutritional Sciences

Adrenal Function and Physical Performance

There is a substantial body of evidence indicating that there may be a causal relationship between stress and intestinal barrier dysfunction (Rodiño-Janeiro et al, 2015), and with a recent study suggesting that IgG-mediated food intolerance may also be associated with impaired physical performance (Kostic-Vucicevic et al, 2017), it is therefore important to consider the impact that chronic stress may play in this area.

Chronic stress can also be detrimental to the health and optimal functioning of the HPA axis and the adrenals themselves (Guilliams and Edwards, 2010) and thus may negatively affect physical performance from another angle.

The adrenal glands play an important role in maintaining human health and wellbeing and for athletes, optimal functioning of the adrenals enables them to sustain the quantity and intensity of workload that their bodies must endure (Brooks and Carter, 2013). This type of intense training or overtraining across an extended period of time can result in adrenal depletion and an Addison-Type overtraining syndrome, where the adrenal glands are no longer able to maintain proper hormone levels (Brooks and Carter, 2013). Supporting the adrenal glands can therefore not be overlooked in any training programme.

Chronic Stress, Cortisol Dysfunction and Sporting Performance 

If the adrenal glands are not supported, an individual’s stress response can become chronic, causing cortisol levels to stay continually high, which can result in cortisol dysfunction (Hannibal and Bishop, 2014). DHEA (dehydroepiandrosterone), another hormone secreted by the adrenal glands, works as an antagonist to cortisol and can to some extent protect against cortisol’s negative effects (Lennartsson et al, 2013). However, if DHEA levels fall, this protective mechanism would also be expected to decrease, especially if cortisol remains high. Research shows us thus prolonged stress has been associated with a rise in cortisol and a simultaneous reduction in DHEA (Izawa et al, 2012). This may be one of the reasons that the Cortisol:DHEA ratio is thought to be a significant marker to help identify adrenal health in terms of HPA axis function (Guilliams and Edwards, 2010). The reason that DHEA falls is due to cholesterol (the precursor to both hormones) being diverted away from DHEA production to the cortisol synthesis pathway. Cortisol is given priority in order to meet the stress demand under which the body is being placed, otherwise known as the pregnenolone steal (Guilliams and Edwards, 2010).

This type of regulation to help deal with short term stress works well, however, if chronic stress is experienced, for example due to overtraining, then the adrenal glands can become overworked potentially resulting in inhibited cortisol and DHEA production. For an athlete, this needs to be avoided at all costs since stress-induced cortisol dysfunction can result in bone and muscle breakdown, as well as fatigue (Hannibal and Bishop, 2014). This may not only negatively affect performance generally, but further compounds the problem by hindering post-exercise recovery. This would potentially make athletes more susceptible to injury and illness, thus jeopardising their fitness and performance gains.

It is therefore important to assess the balance of the adrenal glands, so that an individual’s training program can be adapted, and treatments and strategies put in place to ensure that they are supported before reaching the fatigued state described above. In addition, this will help to modify training accordingly as well as assess any other underlying stressors, such as lifestyle habits, toxicity, infections and nutritional issues.

Adrenal Function Testing and Supporting the Adrenals

Reducing endocrine imbalance through diet and lifestyle changes enables faster recovery and regeneration post training (Stachowicz and Lebiedzinska, 2009). In addition, and perhaps more importantly, avoiding the effects of chronic stress on these glands may mean that no time is required away from training.

Testing cortisol and DHEA levels can therefore be an extremely useful adjunctive diagnostic tool for athletes as it can help to identify whether their adrenals are functioning optimally. This in turn will help determine if there is a need for the individual to implement a tailored stress management strategy to help ensure optimum performance.

The CNS Adrenal Function Profile uses a convenient saliva sample collection method to assess an individual’s cyclic cortisol levels and pinpoint the important cortisol surge. Also included are a morning and evening DHEA measurement to enable the significant Cortisol/DHEA ratio to be identified.

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