Exercise and Hormones: 8 Hormones Involved in Exercising

Every time you exercise, your body releases a cascade of hormones that affect everything from mood and energy to muscle growth and fat burning. Understanding these hormones helps explain why exercise feels so good, why certain types of training produce different results, and how to optimise your workouts for specific goals.

Hormones Released During Exercise

1. Endorphins

The most famous exercise hormones, endorphins are natural painkillers produced by the pituitary gland during sustained physical activity. They are responsible for the “runner’s high” – that feeling of euphoria and reduced pain perception that kicks in after 20-30 minutes of moderate to intense exercise. Endorphin release is why exercise is consistently recommended as a first-line treatment for mild to moderate depression by the NHS.

2. Testosterone

Testosterone increases during and immediately after resistance training, particularly compound exercises like squats, deadlifts and bench press that work large muscle groups. This temporary spike supports muscle protein synthesis and recovery. Both men and women produce testosterone during exercise, though in different quantities. Heavy lifting with lower reps (4-8) produces a larger testosterone response than lighter, higher-rep training.

3. Human Growth Hormone (HGH)

HGH promotes muscle growth, fat metabolism and tissue repair. It spikes during high-intensity exercise, particularly interval training and heavy resistance work. Sleep is the other major trigger for HGH release, which is why recovery and sleep quality are as important as the training itself. HGH production naturally declines with age, making regular exercise increasingly valuable as you get older.

4. Cortisol

Often labelled the “stress hormone”, cortisol is not inherently bad. During exercise, it helps mobilise energy stores and manage inflammation. Problems arise when cortisol remains chronically elevated, which happens with overtraining, insufficient sleep or prolonged psychological stress. Keeping individual training sessions under 60-75 minutes and prioritising recovery helps maintain a healthy cortisol balance.

Hormones That Affect Energy and Mood

5. Serotonin

Aerobic exercise increases serotonin production in the brain, which regulates mood, sleep and appetite. Low serotonin levels are associated with depression and anxiety. Regular exercise is one of the most effective natural ways to boost serotonin – the effects are comparable to antidepressant medication for mild to moderate depression according to research published in the British Journal of Sports Medicine.

6. Dopamine

Dopamine drives motivation, reward and pleasure. Exercise increases dopamine production and sensitivity, which explains why regular exercisers report feeling more motivated and focused in other areas of life. The dopamine response to exercise is one reason it can be genuinely addictive in a positive sense – your brain learns to associate movement with reward.

7. Adrenaline (Epinephrine)

Adrenaline increases heart rate, blood pressure and energy availability during exercise. It triggers the breakdown of stored fat for fuel, which is one reason high-intensity training is effective for fat loss. The adrenaline response is strongest during novel or challenging activities, which is why varying your routine produces better results than repeating the same workout indefinitely.

8. Insulin

Exercise improves insulin sensitivity, meaning your cells become better at using glucose from your blood. This is one of the most important long-term health benefits of regular exercise. Improved insulin sensitivity reduces the risk of type 2 diabetes, supports steady energy levels throughout the day, and helps regulate body fat storage. Both aerobic exercise and resistance training improve insulin sensitivity, with the combination being most effective.

How to Optimise Your Hormonal Response to Exercise

For maximum hormonal benefit, combine resistance training (two to three sessions per week) with aerobic exercise (150 minutes moderate or 75 minutes vigorous per week, as recommended by the NHS). Keep resistance sessions focused and intense rather than long and drawn-out. Prioritise sleep – most beneficial hormones peak during deep sleep, so seven to nine hours is essential for recovery.

Nutrition matters too. Adequate protein supports testosterone and growth hormone function. Complex carbohydrates help regulate cortisol. Healthy fats are precursors to hormone production. Crash diets and severe calorie restriction disrupt hormonal balance and undermine training results.

For practical training advice, see our home gym guide and our yoga for men article for recovery-focused training.

Frequently Asked Questions

Which exercise releases the most endorphins?

Running, cycling and swimming at moderate to high intensity for 30 minutes or more produce the strongest endorphin response. High-intensity interval training also triggers significant endorphin release in shorter timeframes.

Does exercise increase testosterone?

Yes, resistance training temporarily increases testosterone levels, particularly compound movements like squats and deadlifts with heavy loads. The effect is most pronounced in the 30-60 minutes following exercise.

Can too much exercise be harmful to hormones?

Yes, overtraining can chronically elevate cortisol and suppress testosterone, growth hormone and reproductive hormones. Signs include persistent fatigue, mood changes, poor sleep and declining performance. Rest days and adequate recovery are essential.