Close

workout jump

Photo: John Fedele/Getty Images

No other fitness trend has made the same bang as HIIT—high-­intensity interval training. Classes like CrossFit and SoulCycle mix short bursts of all-out activity with a quick recovery breather. But this isn’t the only way to get moving. Enter the HIIT versus LISS debate. HIIT’s low-key cousin LISS, or low-intensity steady-state, is a more relaxed, single-pace workout session you do for longer, like a half-hour jog. “They each have their own benefits, so ideally, you’ll try a combo of both,” says Pete McCall, an exercise physiologist and spokesperson for the American Council on ­Exercise. “But ultimately it’s about which one you enjoy more and will do.” Here, some of the payoffs of each type of exercise.

Read more:Can Walking Really Help you Lose Weight?

HIIT Benefits

It’s efficient.

Both workout styles can help reduce body fat, but you’ll see results in less time with high-intensity workouts. In about 10 weeks, HIITers burned as much fat through 90 minutes of total exercise a week compared to those who did LISS and worked out for two and a half hours, according to a study inObesity Reviews.

It keeps blood sugar in check.

Two weeks of HIIT can improve insulin function (the hormone that regulates blood sugar). LISS helps too, but it’ll take about twice as long before you see a benefit, found research published in theScandinavian Journal of Medicine & Science in Sports.

It improves heart health.

According to a study from theInternational Journal of Environmental Research and Public Health, compared to continuous training, HIIT leads to a more resilient ticker that easily speeds up and winds down based on high or low stress (called heart rate variability), kind of like the automatic transmission in your car. Less variation in heartbeat speed means sticky gears that don’t shift well, which may lead to heart disease.

It gives your metabolism a boost.

Just 20 minutes of HIIT revs your metabolism, helping your body burn nearly 200 extra calories after you leave the gym, found a study in the journalSports Medicine Open.

LISS Benefits

It’s a slow burn.

LISS burns more calories during your workout, found a study in theJournal of Sports Science and Medicine. Plus, its comfortable pace may mean you can exercise longer.

It could help you live longer.

There may be an upper limit to the perks of super-intense workouts. In a study published in theJournal of the American College of Cardiology, joggers running about a 12-­minute mile had a 78% lower risk of pre­mature death, a benefit that sprinters didn’t see.

It’s less risky.

Especially if you’re in less than tip-top shape. “If you work out too hard, too quickly, your body may not be ready to take on HIIT training,” says McCall. “Low-intensity exercise helps prepare your body.” (And, he notes, doing more than three HIIT workouts a week—even if your body is up for it—could lead to injury.)

You might enjoy it more.

Some have a need for speed, but researchers found that previously sedentary adults preferred LISS, per their study in theJournal of Sports Science and Medicine.

The Bottom Line

Was this page helpful?Thanks for your feedback!Tell us why!OtherSubmit

Was this page helpful?

Thanks for your feedback!

Tell us why!OtherSubmit

Tell us why!