Exercise, when done right, “gives your hormones a workout” says Nicky Keay, MB, a sports endocrinology researcher and author of Hormones, Health, And Human Potential.
Working out increases growth hormone, which is key to a healthy body composition, and increases insulin sensitivity, which helps regulate blood sugar, Keay says. It triggers the release of dopamine and serotonin, well known for their mood-boosting effects. Exercise also boosts estrogen1, a reproductive hormone whose decline is to blame for many menopause symptoms, and testosterone, which supports everything from bone health to libido. Several studies have demonstrated that regular exercise can relieve menstrual pain2, which can at least in part be explained by increased progesterone, which has anti-inflammatory effects.
Exercise generally lowers cortisol levels, though exact effects depend on the type, intensity, duration, and timing of exercise. One meta-analysis found that HIIT workouts increased cortisol in the short term (30-60 minutes after) but decreased cortisol levels below baseline within two hours of the workout, with levels returning to normal after 24 hours. Researchers noted that the time it takes for cortisol levels to come back down to earth is longer with HIIT workouts than other less intense workouts. Another study found that cortisol decreased over time with endurance exercise, (cycling for 40 minutes at 75% of maximum heart rate) but decreased more slowly with resistance exercise (30–40 minutes of repeating sets of ten of a series of exercises).
It’s important to note that cortisol isn’t all bad. Besides regulating the stress response, cortisol helps us wake up in the morning and respond quickly to danger, Keay says. “Cortisol is an important hormone so I’m not saying we should try and keep it low,” Keay says. “But equally, we don’t want to encourage it to be overactive when it’s not needed.”
