Last August, when I finally took responsibility for, and got serious about, my wellness, I did a lot of research around diet and exercise best practices. I found many different meal plans, training guides, and other various articles and resources. Many training guides I found mentioned “HIIT” and “LISS”. As a former cardio junkie, unsuccessfully chasing certain goals, I felt enlightened and hopeful when I learned about HIIT and LISS. I hope if they’re new to you, you can feel the same after reading this post!

What are HIIT and LISS?

HIIT and LISS are two different types of cardio, or cardiovascular exercise—any exercise that raises your heart rate.

HIIT stands for High Intensity Interval Training, while LISS stands for Low Intensity Steady State.

Research has shown that a successful exercise routine—producing fat loss and muscle preservation—requires appropriate amounts of both HIIT and LISS.  As you read on, you’ll notice that neither HIIT nor LISS involve boring yourself to death on a treadmill at a running pace for an hour—a tactic believed to be productive by many, yet culpable for the lack of goals met by many of the cardio-obsessed. #tbt and #guilty

What does HIIT look like?

A typical HIIT session lasts 30 minutes or less (some of my favorites—also some of the most challenging and effective—are just 15 minutes). As you could deduce from the acronym, HIIT cardio is performed in intervals. You perform short bursts of high intensity, all-out cardio, followed by short, active recovery periods. There are also generally warm-up and cool-down periods during a HIIT workout. The combinations of exercises you could complete to have a productive HIIT workout are endless. Treadmill sprints, body weight circuits—literally anything that gets your heart working at its max effort.

HIIT has been very popular lately for many reasons, but mainly because it is short-lived (hellooo, convenience!), and also because of its afterburn effect. When you perform such intense exercise, you create an oxygen shortage for your body, which causes your body to demand more oxygen when you’re in the recovery state (aka when you’re not working out, aka a day, or days, later). Yep, you read that correctly. Amazing, right?! *excitedly keeps reading*  That said, HIIT is known to burn calories for days post-exercise. In addition to its metabolism boosting benefit, HIIT can really be performed anywhere—jump squats, burpees, high-low planks, switch lunges, etc. No equipment? No problem.

What does LISS look like?

LISS is essentially the opposite of HIIT. Think light cardio, performed for longer periods of time (about 30-60 minutes). LISS can be performed every day and unlike HIIT, does not contain rest or recovery periods. The point here is to get your heart working and sustain it for a long period of time, causing the fat burn to take place during your work time—whereas HIIT typically has stronger after effects. Examples of LISS can are bountiful too—going for a walk, bike riding, rowing, swimming, etc. A benefit of LISS is that it is much more gentle on your body than HITT, which can be quite strenuous.

How do I make HIIT and LISS work for me?

Of course, as with anything, everyone’s goals and ways of reaching said goals are, and should be, different. That being said, specific HIIT and LISS prescriptions might work wonders for you and not someone else. You have to try out different variations and find what works best for your current fitness level and therefore, what helps you reach your goals. The key here is that you are doing varied cardio, switching it up to keep your body from adapting. You want to keep your body guessing. Just like those endless endurance sessions didn’t work, you don’t want to overload on HIIT or LISS sessions. Find that balance. (…that moment when you’re realizing everything in life is about balance… #deep)

Do you have favorite routines or strategies for tackling HIIT and LISS? Share them with us in a comment or DM!

This post is part of our WTF series—where we’ll break down some of the latest food, fitness, and health + wellness trends blowing up your Instagram feed.