This Fitness Trend Is the Opposite of HIIT—and We Tried It
You're probably thinking: Haven't people been doing that kind of exercise forever? And yes, they have. LISS isn't new, but it's enjoying a bit of a renaissance right now. One probable reason: "People have been overdoing it with high-intensity interval training," says Jessica Matthews, an American Council on Exercise certified personal trainer and assistant professor of exercise science at San Diego Miramar College. "You shouldn't be doing more than two or three HIIT sessions a week, but I see people doing them way more often than that," she says. (This definitely doesn't apply to us, but we'll take Matthews' word that some people can't get enough HIIT.) Their bodies need a break, and that's where LISS comes in.
Think of it as active recovery, says Matthews. You're up, you're moving, but you're not working that hard. On a scale of one to 10, with one being sitting and 10 being all-out effort, LISS should fall at a three or a four the whole time. You can do it with any type of cardio, as long as you stay at a low-intensity level. A LISS session generally lasts longer than a HIIT workout, too—anywhere from 30 minutes to one hour.
LISS can also put some pep in your step. Healthy but tired young adults increased their energy levels by 20 percent, and decreased their fatigue by 65 percent, just by doing regular, low-intensity exercise, found a small study in the journal Psychotherapy and Psychosomatics.
I've been incorporating it into my exercise routine by doing HIIT and LISS on alternating days, based on Matthews' advice. (She says a combination of the two will get you fit, while helping you to avoid overuse injuries and burnout.) If Thursday's exercise was sprint intervals on the treadmill, Friday's workout is an hour-long walk home. Then, Saturday, I'll ramp up the intensity with a group fitness class, such as rowing or boxing. If you have the "if I'm not sweating profusely, it's not a workout" mindset (guilty!), thinking of a long walk as your exercise for the day takes some getting used to. But once you go into Saturday's HIIT session feeling refreshed, instead of freshly sore, and are able to put in more effort than you could if you had done intense workouts Thursday and Friday, you'll get on board quickly.