Your Comprehensive Guide to LISS Cardio

When you think of people tackling cardio workouts, the first image to come to mind might be of breathless athletes with flushed skin and sweat-drenched sports bras. You're not mistaken — some cardio sessions can leave you huffing, puffing, and feeling as if your heart is about to burst out of your chest. But these dreadful effects aren't a requirement to score the cardiovascular benefits the workout method has to offer.

One approachable alternative? Low-intensity, steady-state — aka LISS — cardio, a chiller form of cardio that challenges your heart, is easy on your joints, and is accessible to a variety of individuals. Ahead, two fitness experts break down exactly what LISS cardio entails, its benefits, and how it's different from high-intensity interval training (HIIT) workouts. Plus, you'll find LISS cardio workout ideas to put into practice.

What Is LISS Cardio?

LISS cardio is exactly what it sounds like: a type of aerobic activity in which your heart rate or exertion level is modest and remains pretty stable throughout the workout, says April Gatlin, C.P.T., a personal trainer and Master Coach at STRIDE Fitness. Due to the mild intensity, these workouts are often longer in duration (think: 30 to 60 minutes long) than their vigorous-intensity cardio counterparts, says Gatlin.

Generally speaking, your heart rate might be between 50 to 65 percent of your maximum heart rate during a LISS cardio session, adds Donna Cennamano, a NASM-certified personal trainer and manager of training for CycleBar. (BTW, your maximum heart rate can be estimated by subtracting your age from 220, according to the Centers for Disease Control and Prevention.) But how fast your heart is pumping isn't necessarily the best metric to rely on when determining the intensity of your cardio workout; everyone's body is different, and factors such as caffeine consumption, stress, and certain medications can all impact your heart rate, says Gatlin. "I'm always hesitant to give heart rates out because I don't want somebody to think that if they have [too] high or low [of a] heart rate, they're not doing the work," she explains.

Instead, Gatlin recommends considering your rating of perceived exertion (or RPE) to determine if you're engaging in LISS cardio. On a scale of 1 (you're basically resting) to 10 (you can barely breathe), your RPE should be a 5 or 6 during a LISS cardio workout. "You can feel yourself working, but you can still have a conversation, usually just a sentence at a time," she adds.

LISS cardio workouts typically entail running, brisk walking, cycling, or swimming. However, since RPE will vary from person to person, depending on fitness level and the activity at hand, what's considered LISS cardio for you may be different from your workout buddy, says Gatlin. For example, a brisk walk may leave you a bit sweaty, slightly out of breath, yet still comfortable, but your cardio-fanatic friend may need to go for a jog to feel the same effects.

The Benefits of LISS Cardio

Okay, LISS cardio sounds like a perfect option if you're in the mood for a toned-down workout, but does it have any legit benefits? Here's what Gatlin and Cennamano have to say.

Improves Cardiovascular Health

Mixing low-intensity, steady-state cardio into your routine can do your ticker some good. Cardio workouts in general train your heart and lungs so they're able to deliver oxygen to your muscles more effectively, which ultimately helps you tackle more strenuous activity without feeling totally winded, Melissa Kendter, an ACE-certified trainer, functional training specialist, and EvolveYou coach, previously told Shape.

Although the workout method has "low-intensity" in its name, LISS cardio performed at a 5 or 6 RPE is actually considered moderate-intensity physical activity by the U.S. Department of Health and Human Services (DHHS). The good news: Engaging in 150 minutes of moderate-intensity aerobic activity each week has been linked with significant reductions in the risk of cardiovascular disease and all-cause mortality, according to the DHHS, which is why the department recommends adults score at least that amount weekly.

Has Less Impact On Your Joints

LISS cardio activities are often lower in impact than their vigorous-intensity, interval-style counterparts, such as sprints, plyometric workouts, and HIIT sessions (during which you'll alternate between bursts of vigorous exercise and short periods of active recovery moves or full-on rest). In turn, they're often easier on your knees, feet, hips, and low back and may be more suitable for older folks or individuals dealing with other joint-related ailments, says Gatlin. For these people, "LISS cardio gets their heart rates up in a less impactful way, so it's probably more beneficial for them just to go on a 30-minute walk every day than doing sprints," she explains. And on that note...

Works for a Variety of Populations

Thanks to the low-impact, chill-intensity nature of LISS cardio workouts, they're generally accessible to a variety of populations, including elderly individuals and people with orthopedic issues, says Gatlin. "[LISS cardio] can really meet every person out there, somehow and some way," she says. A vigorous HIIT workout can be challenging for certain populations, she says, but most folks, regardless of their abilities, can find and take part in a LISS activity that gently raises the heart rate and syncs with their needs.

LISS cardio also enables exercise newbies and people recovering from injuries to return to movement, adds Cennamano. "They can work on adding time and intensity to the workout in increments," she explains. For example, someone who hasn't done cardio in decades can start off with brisk walks around the block, gradually increasing the time spent on the activity. Once their cardiovascular system is conditioned to the workout, they can move on to jogs, says Gatlin. "[It's] sustainable and attainable without compromising safety or increasing the chance of injury," notes Cennamano.

Challenges Your Body In Different Ways

Even diehard HIIT fans and injury-free individuals can benefit from incorporating LISS cardio into their fitness routines. Over time, your body will adapt to the exercises you're performing regularly, and your progress in the gym may slow down or come to a standstill as a result, says Gatlin. That's why she recommends keeping your body guessing by incorporating different LISS cardio workouts into your schedule. "Nothing bad is going to happen from doing that," she adds. "It's nice to ask your body to deliver in different ways, and that's only going to strengthen the body and heart. Take a look every four to six weeks and ask, 'Is my body getting used to these workouts…and how can I challenge myself in a different way?"

LISS Cardio vs. HIIT

HIIT is essentially the polar opposite of LISS cardio. Since the training method involves alternating between bursts of vigorous activity and short rest periods, it utilizes your body's anaerobic energy system — not your aerobic one like LISS cardio, says Gatlin. Refresher: During aerobic exercise, your body will utilize your stored carbs, protein, and fat, plus the oxygen you breathe, to make energy readily available to your muscles. Consequently, you can carry out the activity for prolonged periods of time, according to information published by Piedmont Healthcare. During anaerobic activity, on the other hand, your body will utilize just the energy that's already stored in your muscles, so you can sustain the exercise only for short bursts of time, according to Piedmont Healthcare.

And each of these types of workouts has unique benefits. Aerobic exercise helps strengthen your slow-twitch muscle fibers, which contract slower and enable you to train for long periods of time before you start to feel fatigued. On the flip side, anaerobic exercise boosts the size and quantity of fast-twitch muscle fibers, which increases your muscle's power and strength, according to the International Sports Sciences Association. Despite this distinction, experts say focusing on training specific fiber types isn't necessary, as "the fibers just do what they need in order to make you more efficient at whatever training you're doing," Ian Elwood, M.A., A.T.C., C.S.C.S., C.F.-1, previously told Shape. All that's to say neither workout is better for your body than the other — they're simply different.

Still, drawn-out LISS cardio sessions may feel boring at times, challenging your focus and motivation, says Cennamano. And that's where HIIT workouts, which often take less than 30 minutes, may have a leg up. "A reason why so many people prefer HIIT is not just because of the efficiency of the workout — [you can] achieve results [i.e. improved cardiovascular health] in less time — but the engaging and often unexpected element of it," she adds. "Instructors and trainers have a lot more leverage with programming choices and can vary activity from session to session." During each HIIT workout you tackle, you might spend 15 minutes powering through a handful of different plyometric exercises with short rest breaks in between. The result: a fitness routine that doesn't go stale after just a few weeks.

The Best LISS Cardio Workouts

Ready to mix LISS cardio workouts into your routine and start scoring those perks? Try out some of the workout methods below. If it's too challenging to do a 30-minute workout right from the get-go, start off with a five-minute session, then increase it by a minute each week, says Gatlin. And remember to check in with your RPE throughout your session to ensure you're keeping your intensity at a level 5 or 6.

• Swimming
• Cycling
• Walking
• Jogging
• Rowing