Sometimes it feels like the world of fitness changes more quickly than the Hollywood dating scene. And in the trend-driven world of today, the old health mantra of “no pain, no gain” may be a thing of the past.

What is LISS?

The newest fad on the block is a four-letter acronym (and sorry HIIT, it’s not you!). LISS is the buzzy exercise of the moment. Standing for low-intensity state cardio, LISS is the gentler, steadier, more relaxed workout sibling of HIIT (high-intensity interval training). With LISS, you maintain the same pace of any cardio activity of your choice — whether that be swimming, elliptical, or even walking. While HIIT is great to get your heart rate pumping in a short period of time, LISS can also help you to tone up, burn fat, and actually stick with a workout routine.

Is LISS a new thing?

Truth be told, LISS is not a new trend. It’s been around for as long as we have been power walking, and it refers to exercise performed at or below 60-65 percent of maximum heart rate at a consistent level of intensity, for 20 minutes or longer. However, the term has become more popular as of late thanks to a recent spate of high-profile fans, including Instagram star and personal trainer Kayla Itsines, creator of the popular Bikini Body diet and workout program. She encourages her 6.3 million followers to partake in a combination of low-impact and high-impact workouts for maximum fat loss.

Is HIIT to be forgotten?

But don’t get us wrong. Even with the growing interest in LISS, HIIT is still popular and delivers major health bang for your buck. Involving quick bursts of extreme physical activity, it has a devoted following in popular classes such as Barry’s Bootcamp and CrossFit. There is also research to back up its benefits: HIIT helps to burn more fat, increase endurance, and promote healthy blood sugar levels. One issue? HIIT workouts tend to be pretty intense and sometimes unpleasant (after all, who enjoys endless sets of burpees or sprints?), which can lead to burnout and even injury. Research from the Journal of Sports and Science Medicine found that subjects reported HIIT to be significantly less enjoyable compared to other exercise, and that when it comes to getting in shape, LISS can be just as effective.

So why should you add LISS to your workout routine?

Because, sometimes, the most effective workouts may just be the simplest ones. In today’s all or nothing culture, a lot of people have unrealistic expectations about fitness, going full-throttle with a heavy duty exercise routine and then ending up disappointed or burned out, or injured. Getting back to the core idea of what exercise is supposed to be about, which is simply physical activity to sustain or improve health, can help to make a routine stick.

It’s not about fancy classes or equipment, it’s about boosting your energy, your mood, and your heart rate. So balancing out those SoulCycle classes with some lower intensity cardio sessions may be just what you need. “LISS's greatest benefit may be to act as a stand-in or complement to a high-intensity exercise regimen,” says Timothy Coyle, M.S., CEO of Cado Health Solutions, a health consulting firm, and assistant professor of exercise science at Long Island University-Brooklyn. “It will keep you moving on a day where you want to do something, but perhaps an intense workout isn’t the answer.”

Who can do LISS?

Whether you are embarking on a new fitness routine, have a jam-packed schedule, or just plain do not enjoy hardcore workout classes, LISS can be done by anyone, anywhere, at any time. You don’t need access to a gym or to attend pricey classes, and there are tons of options: hiking, light jogging, swimming, and even walking. Especially for those new to cardio, LISS can help to build endurance. For those who prefer more intense workouts, LISS is a great option for recovery days or even as a de-stressor. LISS is also a good alternative to the more intense cardio used for serious endurance training, as in marathons.

What are the health benefits of LISS?

The lower-intensity aerobic workouts help to burn fat and can also reduce your risk of diseases such a diabetes, maybe even more so than vigorous exercises. A 2013 study in PLOS One found that longer durations of low-intensity activity such as walking can improve your insulin sensitivity and blood lipid levels more than short bursts of vigorous exercise.

This isn’t to say you should quit your CrossFit membership and plan on only power walks from here on out, but adopting an exercise regimen that encompasses both lower and higher intensities can lead to sustained health.

The bottom line?

Get moving! Whether it’s HIIT, LISS, or another workout you enjoy, exercise of any type can help you to tone up, prevent disease, and feel better.