4) Cortisol⬇️, Endorphins⬆️
Chronic stress = constantly high cortisol (the stress hormone) >> keeps your brain wired, blocks deep sleep, and suppresses melatonin at night. Regular exercise lowers baseline cortisol over time by training your HPA-axis (stress response system) to be less reactive.
At the same time, movement triggers release of endorphins (natural opioid-like peptides) that bind to brain receptors >> creates calm, reduces anxiety, and promotes relaxation. Result: calmer brain chemistry, lower evening cortisol, easier wind-down, and better sleep quality.