Hormones and Exercise: How Physical Activity Optimises Your Hormonal Health

Testosterone and exercise

Resistance training produces acute testosterone elevations of 15–25% in the hour following training. With consistent training over months, baseline total testosterone is typically higher in trained individuals than sedentary ones of the same age.

The mechanism involves direct stimulation of Leydig cells (in men) and adrenal androgen production (in both sexes), as well as improvements in body composition (reduced adiposity) that remove aromatase-driven testosterone-to-oestrogen conversion.

Which training produces the most testosterone response?

Heavy compound resistance training (squats, deadlifts, bench press) involving large muscle groups and moderate-to-high intensity produces the strongest acute testosterone response. High-volume, short-rest protocols also produce significant responses.

⚡ Overtraining and testosterone

Excessive training volume without adequate recovery reduces testosterone — a phenomenon well-documented in overtrained athletes who show symptoms of hypogonadism. More training is not always better; recovery is essential for maintaining the hormonal benefits of exercise.

Growth hormone and exercise

Growth hormone (GH) is powerfully stimulated by both resistance training and high-intensity aerobic exercise. It plays critical roles in muscle protein synthesis, fat metabolism, bone growth and tissue repair. GH declines significantly with age (the 'somatopause'), and exercise is one of the most effective natural interventions to maintain GH output.

Sleep — the primary GH stimulus

The majority of daily GH release occurs during deep sleep — approximately 70% is released during the first hours of the night. Exercise enhances deep sleep quality, creating a positive feedback loop: more exercise → better sleep → more GH release.

Insulin and exercise

Skeletal muscle is the primary site of insulin-mediated glucose disposal — it accounts for up to 80% of glucose uptake following a meal. As muscle mass declines, insulin resistance typically worsens. Exercise improves insulin sensitivity through multiple mechanisms: increased glucose transporter expression, enhanced insulin signalling pathways, and simply increasing the mass of insulin-sensitive tissue.

✅ The key hormonal benefits of exercise

Sustained aerobic + resistance training programme: ↑ testosterone baseline, ↑ growth hormone release, ↑ insulin sensitivity, ↓ cortisol (chronic), ↑ BDNF (brain health), ↑ oestrogen metabolism efficiency, ↓ inflammatory markers. No pharmaceutical intervention achieves this breadth of hormonal benefit.

Frequently asked questions

Does cardio reduce testosterone?

Moderate aerobic exercise does not reduce testosterone and may acutely increase it. Excessive endurance training (high-volume marathon training, overtraining) is associated with reduced testosterone in some studies. The key is balance and adequate recovery — not avoiding cardio.

Should you exercise differently at different times of the menstrual cycle?

Emerging evidence suggests that hormonal fluctuations across the menstrual cycle do affect strength, power and recovery capacity — with the follicular phase (post-period) typically being optimal for high-intensity training. This is an active research area and individual variation is substantial.

See how this affects you personally

Enter your age and lifestyle to get your own personalised body stats — from brain age to heartbeats to lung capacity.

▶ Get My Personalised Report

Hormones and Exercise: How Physical Activity Shapes Your Hormonal Health