Physical activity and hormonal health: the impact of movement on my hormones

Hormones are my body's chemical messengers. They regulate metabolism, mood, sleep, reproduction, growth, immunity and aging. When they are in balance, everything works well. When they become deregulated, under the effect of chronic stress, a sedentary lifestyle or aging, almost all systems suffer.

Physical activity is one of the most powerful and least known interventions for maintaining hormonal balance. It acts simultaneously on dozens of different hormones, with documented beneficial effects on cortisol, insulin, sex hormones, thyroid hormones, leptin, ghrellin and many others. Here is a complete overview.

1. The main hormones influenced by exercise

2. Exercise and cortisol: the stress axis

Cortisol is the hormone most directly affected by our modern lifestyles, and one of the most important to regulate for overall health. Physical exercise has a complex and beneficial relationship with cortisol:

• ●During exercise: cortisol increases transiently (this is normal and useful, it mobilizes energy). This elevation is proportional to the intensity and duration of the effort.

• ●After exercise (short term): cortisol drops below its initial value, creating an effect of post-exercise physiological relaxation. This is why exercise is an immediate stress reliever.

• ●In the long term (regular practice): resting cortisol levels are significantly lower in active people. The HPA (hypothalamic-pituitary-adrenal) axis becomes more resilient and better regulated, the response to stress is more appropriate and the return to calm more rapid.

• ●Beware of overtraining: a very high volume of exercise without adequate recovery can chronically elevate cortisol, with opposite effects. Training-recovery balance is key.

3. Testosterone and growth hormone: the synergy of reinforcement

Muscle strengthening is the exercise that produces the most significant effects on anabolic hormones, those that promote tissue construction and regeneration:

• ●Testosterone: multi-joint exercises with heavy loads (squat, deadlift, bench press, pull-ups) produce the highest post-exercise testosterone peak. This effect is present in men and women, although less pronounced in the latter. Testosterone promotes muscle growth, bone density, energy and libido.

• ●Growth hormone (GH): high intensity exercise (HIIT, strengthening) produces a significant peak in GH in the hours following exercise, amplified by subsequent deep sleep. GH promotes tissue repair, fat mobilization and muscle synthesis. It naturally decreases with age; intense exercise partially preserves this secretion.

• ●IGF-1: increases in response to resistance exercise and contributes to muscle growth, bone health and cell regeneration. Its levels are a good marker of anabolic response.

4. Hormones and weight regulation: leptin and ghrellin

The regulation of appetite and weight depends on two key hormones whose balance is directly influenced by physical activity:

• ●Leptin (satiety hormone): produced by fat cells, it signals to the brain that energy reserves are sufficient. In case of overweight, resistance to leptin develops, the brain no longer receives the satiety signal. Regular exercise improves leptin sensitivity, restoring this regulation.- Ghrellin (hunger hormone): produced by the stomach, it stimulates the appetite. Moderate aerobic exercise transiently suppresses ghrellin during and after exercise, reducing post-session food cravings. Conversely, very intense exercise can increase ghrellin.

• ●The paradox of food compensation: some individuals compensate for the calories burned by exercise with an increase in appetite (via ghellin). Understanding this mechanism allows you to adapt your nutritional strategy so as not to cancel out the benefits of exercise on body composition.

5. Thyroid hormones and basal metabolism

The thyroid, and its hormones T3 and T4, regulates basic metabolism, thermogenesis, energy and heart rate. Physical activity has a positive impact on this often neglected function:

• ●Stimulation of thyroid production: acute exercise transiently stimulates the production of T3 and T4, temporarily increasing basal metabolism.

• ●Prevention of subclinical hypothyroidism: research shows that physically active people are less likely to develop hypothyroidism, particularly through the anti-inflammatory effects of exercise on the thyroid gland.

• ●Muscle mass and metabolism: muscle is the main consumer of thyroid hormones. Maintaining muscle mass through exercise preserves sensitivity to thyroid hormones and avoids metabolic slowdown.

A complete health check-up including a hormonal assessment (cortisol, TSH, free testosterone, fasting insulin, lipid profile) makes it possible to identify imbalances and adapt the physical activity program to correct them. Physical activity is one of the most powerful and least iatrogenic interventions to support hormonal health.