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These 2 Exercises Are the Keys to a Leaner Body Fast, Say Experts

Fitness pros reveal the importance of combining HIIT and LISS.

While we're major proponents of strength training here at ETNT Mind+Body, we're also major proponents of simply mixing up your routine and trying all sorts of things. After all, as we've reported in the past, one of the surefire ways you'll slack on your workouts is by doing the same workout over and over. Whether you're doing different exercises on different days, mixing up your daily runs by adding different intensities and supplemental exercises, or simply trying new sports (golf, anyone?), keeping your workouts fun and fresh is paramount.

That being said, if your aim is to trim fat, tone muscle, and cultivate a leaner physique, experts will tell you that there are two types of exercises you'd be wise to combine into a single weekly routine—regardless of whether you're a fitness beginner or an experienced gym-goer. Read on for what they are, along with some sample moves you can try at home. And for more great fitness advice, don't miss these Secret Tricks for Convincing Yourself to Exercise, Say Experts.


hiit workout

If you aren't familiar with the abbreviations, HIIT stands for "high intensity interval training" and is characterized by pairing short, intense bursts of action with even shorter periods of rest in a cyclic manner. (For example, a cycle of 45 seconds of mountain climbers followed by 15 seconds of rest repeated anywhere from five to 10 times.)

Meanwhile, LISS stands for "low-intensity steady state training" and can be accomplished by any number of moderate-intensity activities such as walking, swimming, or hiking.

Both of these exercise varieties offer their own set of benefits and drawbacks, which is why it's advisable to go for both. That way, you get the best of both worlds while mitigating the negatives on either side. And for more great exercise advice, don't miss the Secret Side Effects of Lifting Weights for the First Time, Says Science.

What Are the Benefits?

young woman running along a rural road, exercise outdoors

LISS exercises are ideal for building endurance, while HIIT is better suited toward explosiveness and strength-building. At the end of the day, though, don't both of those attributes sound pretty appealing?

"If you're looking to do a marathon, mud run or endurance-based activity, put some energy into LISS. But if you're looking to be more explosive, athletic or build muscle, HIIT workouts are best suited to help you do that," Rafique "Flex" Cabral, NASM-CPT and Isopure athlete, recently told Today.

But here's why fitness pros say that you should combine them: Your LISS exercises can be performed on your "rest" days in between bouts of more hardcore HIIT.

"LISS is important because it breaks up your week," Kayla Itsines, PT, recently said at a Women's Health Live Virtual event. "Going for LISS [exercise] is so great for your overall fitness and also for your mind as well. Set a 15-minute timer or a 20-minute timer and go for a walk and when it goes off, come back. It's a really good way to break up your week and still stay active and motivated to do more."

But why do HIIT at all? Well, as far as lean-body exercise goes, science says it's the most bang for your buck. According to one study published in the Journal of Strength and Conditioning Research. Researchers compared calories burned during HIIT and other forms of exercise (weightlifting, cycling, etc) and noted that "caloric expenditure was significantly greater" while performing a HIIT routine over all others.

Another reason why HIIT is essential is its efficiency at promoting post-exercise oxygen consumption (EPOC). In a nutshell, EPOC is the exercise gift that keeps on giving, referring to the number of calories burned after we stop exercising. According to the American Council on Exercise, HIIT workouts are the single best way to stimulate the EPOC effect. Moreover, this study published in the European Journal of Applied Physiology concludes EPOC can continue in the body up to 38 hours post-workout!

"With HIIT you will produce an after-burn effect with 25 percent more calories burned post-workout compared to going for a run or walk," Lisa Reed, MS, CSCS, a performance coach and owner of Lisa Reed Fitness, LLC, told Today. "Maintaining a routine that involves HIIT training three to four times a week will help compound that post-workout effect on your metabolism."

So how often should you be performing HIIT and LISS workouts?

Young sporty fit woman on floor doing bicycle crunch fitness exercise at home

Cabral recommends a 2:1 approach depending on your personal goals. If your endgame is to tone muscle, perform one LISS routine for every two HIIT exercises. If you're looking for more endurance-centric results, do the opposite. "Your fitness goals will determine the balance of what you need to be able to look and perform the way you want. Everyone is different, so finding that balance might take a little trial and error, which is ultimately worth it when you find what works best for you," he added.

If you're looking for specific HIIT and LISS workout ideas, read on. And for more amazing exercise advice, don't miss the Unexpected Side Effects of Working Out in the Morning, Say Experts.

LISS: A 2-4 mile walk

woman walking in a forest

No exercise is as leisurely as a nice stroll. If you can find the time to go for a walk lasting anywhere from 20 minutes to an hour (the longer, the better!), you'll have accomplished a LISS workout for the day. There are also plenty of other reasons to make walking a regular habit, such as a longer life.

HIIT: Burpees


Stand up straight with your feet hip-width apart. From there, squat down and place your hands on the floor while kicking your legs back to land in a planking position. Perform a single push-up and then jump your feet back toward your hands. Once back in an upright position jump as high as you can with your hands over your head. That may sound like a lot, but once you get the hang of it the full burpee movement should be one fluid motion.

Repeat as many burpees as possible within 20 seconds, rest for 10 seconds, and repeat as many times as comfortably possible.

LISS: Hiking


A mild intensity hike provides all of the perks of a walk while adding in the extra benefits of walking on an incline. Inclined walking is known to promote more burned calories, stronger calves, and improved posture.

HIIT: Plank jacks

plank to pushup

Start out in a planking position with your ankles together. Tense up your abs and take a moment to ensure your body is positioned in a straight line. From there jump both feet out wide and then back together again. Repeat as many times as possible for 20 seconds, rest for 10 seconds, and repeat as many times as comfortably possible. And for another exercise move you should do, make sure you're aware of The Single Greatest Weightlifting Move for Shedding Pounds, Says Science.

John Anderer
John Anderer is a writer who specializes in science, health, and lifestyle topics. Read more about John
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