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The Role of Hormones in Athletic Performance

No matter your chosen sport, in the quest for athletic success, we all have the aim of maximising our potential. That’s where hormones play a crucial role.

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Published on

March 19, 2019

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If you’re an endurance athlete, then your training will be focused on building a strong cardiovascular system and optimising energy efficiency. If you are a strength athlete, your training will be quite different, focused more on
muscle hypertrophy and power.

In order for your training to be effective, your bodies must respond to the training load placed upon it in a positive way. It is the body’s internal mechanisms that bring about change and progression. And this is where hormones come in.

Hormones are crucial not only for health but for supporting athletic performance.

We spoke to Dr Nicky Keay, an expert in Sports & Exercise Medicine, to find out more.



Hormones are simply chemical messengers, which are released by your endocrine glands throughout the body, and are transported in the blood.

The hypothalamus, located in the brain, controls the endocrine system. It acts as the gatekeeper, integrating internal messages from the body and external factors such as exercise and sleep to regulate the release of hormones from the pituitary gland.

The hormones from the pituitary gland travel round the body to the endocrine glands – such as the thyroid, adrenal, ovaries and testes.

These glands release hormones such as thyroxine, cortisol, oestrogen and testosterone respectively in the blood stream.

Hormones facilitate the type of adaptation to exercise, such as stimulating certain proteins for building muscle, or synthesising enzymes that improve the handling of glucose in a cell, and are crucial for endurance.

Dr Keay explains: “The adaptations to support improved fitness actually occur after exercise, during recovery. This is why rest and recovery is such an important part of any training schedule. It is only during these periods of rest that hormones are released. They backup and drive the longer-term adaptations for both endurance and power athletes. Hormones are not only key for health, but for athletic performance as well.”

To maintain an optimal hormonal response, balancing the 3 key elements of nutrition, training load and recovery is crucial.

harnessing hormones through behaviour infographic

In order to keep the levels of hormones circulating in the blood at an appropriate level, feedback loops exists. The circulating hormones tell the brain whether more/less/equal activation is required. With such an intricate and dynamic network, you can appreciate that if you overload your endocrine system, be it with heavy training, lack of recovery or poor nutrition, then things can get out of sync and you will not be able to train and compete to your full potential.

Monitoring key hormones with biomarker tracking can therefore provide you with valuable feedback.


There are 6 key hormones for athletes and sports professionals, these are:


Growth hormone supports healthy body composition and bone health. You can optimise your natural GH production easily, as two of the main stimuli for GH release are sleep and exercise.


Thyroxine (T4) regulates the rate of metabolism as well as bone health. T4 is converted in the tissues to the more active T3. Overtraining and/or low energy availability can lead to suppression of T3.


Oestrogen is an ovarian response hormone and is released by the ovaries.

Oestrogen is a power hormone as it has a wide-ranging role in women’s health, particularly bone and cardiovascular health (and is why, when women reach menopause, both bone and cardiovascular health can become more fragile).

In the case of insufficient energy availability, young women can effectively become menopausal, with an increased risk of bone stress injuries.


In men (and to a lesser extent, women), testosterone supports lean body composition and bone health. Similarly to women, in the case of low energy availability, low testosterone will occur, increasing the risk of injury.


Cortisol is another hormone of particular importance to athletes.

Cortisol is released in a diurnal pattern, in other words, levels of cortisol are higher in the morning and lower during the night when we are asleep.

Overtraining, low energy availability and/or other causes of stress can disrupt this diurnal pattern of cortisol release causing levels to remain elevated.

Not only can this lower immunity, but a disruption in the natural fluctuations of cortisol levels can also have an adverse knock-on effect on the other hormone systems.


At Edge, we offer a range of at home finger prick blood tests that allow you easily measure and track your hormone balance and the impact your sport is having on your hormone network.
The tests include:

  • Thyroid stimulating hormone

  • Thyroxine (T4)

  • Triiodothyronine (T3)

  • Cortisol

  • Oestradiol (oestrogen)

  • Testosterone

As well as other biomarkers key to health and nutrition.

Results are delivered within 2 working days of our UKCAS accredited labs receiving your sample and are reviewed by our healthcare professionals. Results are released onto your own, personalized and secure results dashboard.

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  1. Sports Endocrinology – what does it have to do with performance?

  2. British Journal of Sport Medicine 2017