We all know how bad chronic stress is for our bodies and for our well-being. And it makes sense that the best way to counterbalance stress would be to relax, meditate and practice yoga. But what if it isn’t necessarily that black and white?
What if high-intensity workouts — ones that are unabashedly stressful — could also help reduce stress?
While there isn’t research looking directly at HIIT and stress relief, “in general, almost any kind of exercise improves mood,” says Matthew Stults, PhD, an exercise physiologist at Yale University.
So yes, you may not exactly enjoy busting out burpees and squats until you can’t breathe or sprinting on and off while it’s happening, but you know that when it’s done, you’ll get that endorphin high.
“It’s hard to start, but once you do and then you finish, you get more endorphin release versus a moderate-intensity session,” says Abbie Smith-Ryan, PhD, who has studied high-intensity interval training in various populations, including overweight and obese people.
“Getting through a very challenging workout could provide a sense of achievement and accomplishment that one may or may not receive from a yoga workout,” says Marcus Kilpatrick, PhD, an associate professor at the University of South Florida.
He cites self-determination theory, “which suggests that we tend to seek out experiences that provide us with a sense of competence,” he explains. “The same could be said of yoga, I suppose, but I would favor something more objectively difficult as meeting this need for self-efficacy and competence.”
But what about the fact that high-intensity interval training boosts cortisol, our “stress hormone”?
“It’s a good response,” says Mike Ormsbee, PhD, interim director for the Institute of Sports Sciences and Medicine at Florida State University. “This happens because your body perceives intense exercise as a threat, so you need to mobilize glucose from your cells to use as energy. You have that cortisol increase, but then hours later it will drop because you just accomplished a hard workout and you feel great after that.”
That drop is what’s key, because it’s long-term high cortisol that’s associated with stress, says Smith-Ryan, an assistant professor in exercise and sports science at the University of North Carolina, Chapel Hill.
Another reason cortisol levels aren’t a great measure of stress is that it’s sometimes hard to translate what happens in a hyper-controlled lab setting to the real world, Ormsbee adds. So just because a study shows one exercise boosts stress or relieves anxiety doesn’t necessarily mean that’ll happen in the gym.
That’s because in the gym, you may encounter things that cause stress — even on a yoga mat.
“If you look around and see everyone up in handstands, that can stress you out instead of calm you down,” says Kimberly Fowler, founder and CEO of YAS Fitness Centers, which offers yoga, indoor cycling and HIIT classes. “Or you may be concerned about not being fit enough or wearing the wrong clothes.”
“Yoga has amazing properties,” she continues, “but not everyone likes it.”
Plus sometimes you just can’t squeeze in an hourlong session, and HIIT is time-efficient. “People stress out about working out and think they have no time, so HIIT is a good solution because you can do a session in 20 minutes,” Smith-Ryan says.
“We know personal preference for exercise and type or mode of exercise has a strong effect on how it impacts your mood,” Stults says.