HIIT vs LISS: Which One Is Right For You?

Cardiovascular health is important for everyone. It translates to a lower risk of heart disease, stroke, and other chronic conditions. And while there are many ways to improve your cardiovascular health, one of the most effective is through exercise.

There are two main types of cardio: high-intensity interval training (HIIT) and low-intensity steady state (LISS). Both have their own benefits and drawbacks.

HIIT is a type of cardio that involves alternating between short bursts of high-intensity exercise and periods of rest or low-intensity exercise (6). HIIT can be done with any type of activity, but is most commonly done with running, biking, or rowing.

LISS is a type of cardio that involves maintaining a steady level of low-intensity exercise for an extended period of time (7). LISS can also be done with any type of activity, but is most commonly done with walking, light jogging, or elliptical training.

So, which one is right for you? It depends on your goals. Let’s take a closer look at different health and fitness goals you may have and which type of cardio would be best for each one.

GOAL: Cardiorespiratory Fitness, VERDICT: HIIT

Cardiorespiratory fitness refers to the health of your heart and lungs. The measures of cardiorespiratory health are VO2 max and heart rate reserve (3).VO2  max is the maximum amount of oxygen your body can utilize during exercise. Heart rate reserve is the difference between your resting heart rate and your maximum heart rate.

Both HIIT and LISS can improve cardiorespiratory health, but HIIT is more effective. Several studies have shown that HIIT can improve VO2 max by up to 10% while LISS only improves it up to 3% (1). 

This is because HIIT

• causes your heart to work harder
• forces your body to use more oxygen
• results in greater cardiorespiratory fitness gains.

A common misconception is that HIIT isn’t safe for individuals with cardiovascular risks because of the high intensity. However, HIIT has actually been shown to be safe for individuals with cardiovascular risks (5). 

The American Council on Exercise recommends both pre-screening and a gradual progression when starting HIIT to minimize complications during and after exercise.

Read More: A Treadmill HIIT Workout That’s Simple And Effective

GOAL: WEIGHT LOSS, VERDICT: LISS

HIIT is often touted as the best type of cardio for fat loss because it’s more efficient. You can burn more calories in a shorter amount of time with HIIT than you can with LISS.

This reasoning overlooks the only condition under which HIIT is more effective for fat loss: if you continue to burn calories after your workout is over. This is called the “afterburn effect” and it only occurs when you do HIIT at a very high level of intensity (think all-out sprints).

For most people, the afterburn effect from HIIT is minimal. In fact, one study found that the afterburn effect from HIIT was only about 6% greater than the afterburn effect from LISS.

So if you’re looking to lose weight, LISS is probably a better choice. That’s because it:

• Has a longer duration, which means you’ll burn more calories overall.
• Is more likely to create a significant calorie deficit, which is necessary for weight loss.
• Is less intense, which reduces the likelihood of cortisol (a stress hormone) being released. Cortisol can contribute to weight gain by increasing appetite and promoting the storage of fat.

GOAL: MUSCLE GAIN, VERDICT: HIIT

If you’re trying to build muscle, HIIT is a better choice than LISS. That’s because HIIT:

• Triggers the release of growth hormone, which helps with muscle building.
• Increases testosterone levels, which also aids in muscle building. 
• Is more likely to create an anabolic environment in the body, which is necessary for muscle growth.

Anaerobic exercise like HIIT is also better at promoting muscular endurance. This means you’ll be able to lift heavier weights for longer periods of time without getting fatigued. 

So if you’re looking to build muscle, HIIT is the way to go (4). Just make sure you’re giving your body adequate time to recover between HIIT workouts (1-2 days) to avoid overtraining.

GOAL: BONE HEALTH, VERDICT: LISS

Osteoporosis is a condition that causes bones to become weak and brittle. It’s a major problem for older adults, especially women. 

Weight-bearing exercises like walking, running, and jumping help to strengthen bones and prevent osteoporosis (8). That’s because they force your bones to work against gravity, which stimulates them to grow stronger. 

HIIT is a weight-bearing exercise, but it’s not as effective as LISS for bone health. That’s because HIIT is of shorter duration and isn’t as consistent, which means it doesn’t provide the same stimulation to bones that LISS does.  

LISS, on the other hand, is a great choice for bone health. That’s because it:

• Is of longer duration, which provides a greater stimulus to bones.
• Is more consistent, which also helps to stimulate bone growth.
• Is less likely to cause injuries, which is important since osteoporosis makes bones more susceptible to fractures.

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HIIT vs LISS: Which One Is Right For You?

Despite each of the factors above, the best type of cardio for you is ultimately the one that you enjoy and will stick with. If you hate running, there’s no point in trying to do it just because it’s “better” for fat loss. You’re far better off doing a type of cardio that you actually enjoy and will stick with long-term.

If the idea of doing HIIT sounds torturous, or if you can’t stand the monotony of LISS, you won’t be consistent enough to reap any benefits from either type of cardio. The best cardio is the one that you’ll actually do on a regular basis. 

So if you enjoy HIIT, do HIIT. If you enjoy LISS, do LISS. And if you enjoy both, do both! Just make sure that you’re giving your body adequate time to recover between HIIT workouts (1-2 days) to avoid overtraining.

Tips For Effective Cardio

No matter which type of cardio you choose, there are a few things you can do to make sure you’re getting the most out of it. 

Track Your Heart Rate

The difference between HIIT and LISS is the intensity level. HIIT should be done at around 80-95% of your maximum heart rate, while LISS should be done at around 60-70%.

You can use a heart rate monitor to make sure you’re staying within the correct range. You may have a general idea of how hard you’re working, but without tracking your heart rate, it’s impossible to know for sure. 

Your heart rate will help you settle on the right length of time for your HIIT intervals. For example, if you’re doing HIIT on a treadmill, you might start with 30 second sprints followed by 60 seconds of walking. If your heart rate doesn’t fall below 80% during the 60 seconds of walking, you know you need to increase the length of your walking intervals. 

Work On Improving Your Anaerobic Threshold

Your anaerobic threshold (AT) is the point at which your body can no longer produce energy aerobically. This is the point at which you have to start relying on anaerobic metabolism to produce energy, and it’s also the point at which lactic acid starts to build up in your muscles (2).

Lactic acid is what causes that burning sensation in your muscles when you’re working out hard. It’s also what makes HIIT so effective for fat loss, since it forces your body to use more fat for fuel.

The problem is, most people have a very low AT, which means they can’t tolerate much HIIT before their muscles start to burn. This is why HIIT can be so tough, and it’s also why most people can’t do HIIT for very long.

If you want to be able to do HIIT for longer periods of time, you need to work on improving your AT. The best way to do this is by slowly increasing the length of your HIIT intervals over time. But before that, using LISS to improve your aerobic capacity is a good place to start.

Start with 15-20 minute LISS workouts and gradually increase the length of time as you get more comfortable. Once you’re up to 45 minutes or more, you can start adding in HIIT intervals. Start with 30 second sprints followed by 2 minutes of easy walking, and gradually increase the length of your sprints as you get more comfortable.

Read More: Beach Body HIIT Workout For Beginners

Master The Correct Form

Walking, jogging, stair climbing and running are all natural movements that we’ve been doing since we were kids. But that doesn’t mean they’re easy to do correctly. In fact, many people have terrible form when they run, which can lead to injuries and make your cardio workouts less effective.

If you want to get the most out of your cardio workouts, it’s important to master the correct form. Proper running technique includes things like keeping your head up, maintaining a tall posture, swinging your arms back and forth, and landing on your midfoot. 

Wear The Right Shoes

This may seem like a small detail, but it’s actually very important. Wearing the wrong shoes can lead to injuries, and no one wants that.

Make sure you’re wearing shoes that are comfortable and provide adequate support. If you’re going to be doing a lot of running, make sure you have a good pair of running shoes.

And if you’re going to be doing HIIT workouts that involve a lot of jumping and lateral movement, cross-training shoes would be a better choice. 

Rest

An understated but important part of getting the most out of your cardio workouts is making sure you’re getting enough rest. When you don’t get enough sleep, your body can’t recover properly and you’ll start to feel rundown.

This will make it harder to push yourself during your workouts, and it will also make you more susceptible to injuries. Make sure you’re getting at least 7-8 hours of sleep per night, and if you can, try to get 9 or 10.

You should also make sure you’re taking rest days between workouts. This will give your body time to recover and prevent you from overtraining.

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The Bottom Line

HIIT and LISS are both great cardio workouts, but they’re not the same. HIIT is a more intense workout that’s better for fat loss, while LISS is a less intense workout that’s better for improving your aerobic capacity.

Both types of workouts have their place, but ultimately it’s up to whichever you enjoy and can sustain for the long term. If you want to get the most out of your cardio workouts, make sure you’re using proper form, wearing the right shoes, and getting enough rest.