The big picture
Hormones regulate metabolism, energy use, appetite, recovery, and adaptation. No hormone acts alone—results depend on the whole system: training, diet, sleep, stress, and energy balance.
Key hormones (overview)
- insulin & glucagon: blood glucose and fuel storage/mobilization
- adrenaline/noradrenaline: acute performance and mobilizing fuels
- cortisol: stress response and energy regulation (problem is chronic stress, not short spikes)
- growth hormone: recovery-related, often oversold for fat loss
- testosterone: supports performance and tissue maintenance
- estrogens: metabolism, bone/tendon health; changes after menopause matter but do not override energy balance
- leptin & ghrelin: appetite regulation signals
What happens during training
During exercise, catecholamines rise, fuel mobilization increases, cortisol rises transiently, and insulin sensitivity improves. Recovery is where adaptation is built.
Practical takeaways
- Hormones matter, but they do not cancel energy balance.
- Long-term results come from consistent training, nutrition, sleep, and stress management.
- Be skeptical of “one hormone” explanations and miracle claims.