Hormones & Training

Why are hormones so important?

With society’s increasing focus on health and fitness, many people are discovering the benefits of exercise and its connection to hormonal health. Over 50 hormones have been identified in humans and other vertebrates and in this article we will explore how exercise can improve hormonal function and what the effects are for different kinds of people.

What are hormones?

Hormones are like chemical messengers that are released into the blood stream to act on an organ in the body. The hormones will then go through the body to reach the targeted cells with compatible receptors.

What do hormones do?

Hormones control or regulate many biological processes and are often produced in very low amounts within the body. For example, such processes include:

  • blood sugar control (insulin)
  • differentiation, growth, and function of reproductive organs (testosterone (T) and estradiol, also called oestradiol)
  • body growth and energy production (growth hormone and thyroid hormone).

Many hormones act by binding to receptors that are produced within cells. When a hormone binds to a receptor, the hormone-receptor complex switches on or switches off specific biological processes in cells, tissues, and organs.

Some examples of hormones include:

  • Estrogens are the group of hormones responsible for female sexual development. They are produced primarily by the ovaries and in small amounts by the adrenal glands.
  • Androgens are responsible for male sex characteristics. Testosterone, the sex hormone produced by the testicles, is an androgen.
  • The thyroid gland secretes two main hormones, thyroxine and triiodothyronine, into the bloodstream. These thyroid hormones stimulate all the cells in the body and control biological processes such as growth, reproduction, development, and metabolism.

The endocrine system, made up of all the body’s different hormones, regulates all biological processes in the body from conception through adulthood and into old age, including the development of the brain and nervous system, the growth and function of the reproductive system, as well as the metabolism and blood sugar levels. The female ovaries, male testes, and pituitary, thyroid, and adrenal glands are major elements of the endocrine system.

What has training got to do with Hormones?

Hormones are secreted in response to events in the external environment such as eating, training or stress and studies have shown that exercise can cause a release of hormones such as testosterone which affects mood and reproductive functions in males or progesterone which affects menstrual cycles in females. Regular physical activity also helps maintain healthy levels of thyroid hormone which supports metabolism.

A good example I can use would be hypothyroidism:  Hypothyroidism is a condition that can cause symptoms like fatigue, weight gain, achy & stiff joints, and low energy. Then even regular low activity exercise (five to seven days a week whenever possible, like walking, using an exercise bike, light weights, or swimming) is sufficient to have a benefit in boosting your energy levels and metabolism. Just getting the heart rate up to be around 50 percent of your max heart rate to help, because one of the side effects of hypothyroidism is depression, and exercise can help with depression when the body releases endorphins a chemical that carries messages to your brain and central nervous system. In addition, lower-impact exercises, such as weight training also builds muscle, which aids in weight maintenance.

Hormones and Athletes

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

Growth Hormone (GH)

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

Thyroxine (T4)

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.

Triiodothyronine (T3)

T3 is a second thyroid hormone that is produced by the thyroid gland. T3 helps maintain muscle control, brain function and development, heart and digestive functions


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.

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 and in the cases 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, that means the 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.

Some athletes are advised to regularly monitor their hormonal function because it so influential on their performance.

For example: Overtraining syndrome (OTS)

This happens when the balance between training and recovery do not match. So, if your recovery after intense physical exercise is too short, the body will not be able to return to homeostasis. If exercise continues before recovery completes, an accumulation of fatigue occurs. At early stages of OTS, you should notice a decrease in performance and fatigue in the athlete, which can be overcome with a longer recovery period. However, if overtraining syndrome continues, more long-term problems occur that change the physiology of the body and can take months to overcome.  Gonadal and adrenal steroids have been used as biomarkers of overtraining in athletes and can be used to assess whether an athlete is in early or late stage OTS.


This website uses cookies. By continuing to use this site, you accept our use of cookies.