Q: I’ve been told I should strive to lower my levels of the stress hormone cortisol, but I’ve also learned that cortisol levels rise during exercise. How do I tamp down my cortisol output without giving up my workouts?
A: It’s true that exercise can cause the fight-or-flight hormone cortisol to spike temporarily, and that elevated levels of this hormone can cause catabolism (muscle breakdown) and a weakened immune system. That might lead you to conclude that if you’re trying to keep cortisol low, you should avoid exercise altogether.
Not so fast. “The body has different hormonal responses to different types of activity,” explains Jonathan Mike, CSCS.
Whereas extended, continuous low-effort exercise like easy running and cycling can cause a potentially damaging rise in stress hormones — particularly in stressed-out types whose adrenal glands may already be overtaxed — exercise involving brief periods of work followed by rest, such as strength training and sprinting, typically does not.
“Short-term increases in cortisol are not catabolic,” Mike says. Far from causing you harm, in fact, the brief spike in cortisol that occurs during and after strength training indicates that the workout is probably doing you a lot of good.
As long as you’re feeling up to it and allowing 48 hours between sessions that stress the same parts of the body, you can do sprint and resistance work three to five times a week. “Regular exercise creates a better adaptive response to stress,” says Mike.
So if you’re trying to keep stress hormones in check, don’t go overboard on endurance exercise. Strength and interval training, however, present no problem.