What Is Low-Intensity Interval Training (LIIT)?

Low intensity interval training (LIIT) consists of periods of low impact exercise performed in intervals combined with longer periods of rest than you might have with a HIIT (high intensity interval training) workout. LIIT is deal for people who are older, new to exercise, or recovering from an injury.

LIIT provides a workout without putting as much stress on your heart as HIIT. In fact, you can still expect to get your heart rate to increase, but in a way that is more manageable.

Here is what you need to know about LIIT and whether it's the right workout for you.

Difference Between LIIT and HIIT

Regardless of whether you are doing LIIT or HIIT, you will perform repeated bouts of exercise separated by rest periods. The primary difference between the two is the level of intensity or how hard you work.

With HIIT, you are pushing your body outside of your comfort zone or working at about 80% to 95% of your maximum heart rate. Meanwhile, with LIIT, you are working moderately hard or nearly 70% of your maximum heart rate or lower.

There are pros and cons to both types of interval training. Choosing between the two will depend on your goals and your overall fitness level. For instance, LIIT may be better suited for older people, beginning exercisers, those who are recovering from an injury, and people with obesity.

In fact, researchers found that people with obesity who exercised at lower intensity lost around the same amount of weight and reduced their waist circumference as those who pushed themselves harder. Meanwhile, those who exercised at higher intensities did have greater improvements in cardiorespiratory fitness.

LIIT Workouts

Because LIIT workouts are more about the intensity of the workout than the actual exercise itself, you can adapt almost any circuit into a LIIT workout. You can even take a HIIT workout and turn it into a LIIT workout by reducing the intensity and increasing the rest period. Here are some ideas of exercises you can do. Just be sure to keep the intensity in the lower range and allow your body to rest before moving on.

• Treadmill workout: After a brief warmup, start by walking briskly—or even jogging—on a treadmill for 90 seconds. Aim to keep your heart rate around 50% to 70% of your maximum heart rate. Once the 90 seconds is up, walk for the next 3 minutes, allowing your heart rate to come back down. Repeat these intervals until you have exercised for about 40 to 45 minutes.
• Bodyweight workout: After a brief warmup, do 10 squats, followed by 90 seconds of rest or walking around. Then do 10 lunges followed by 90 seconds of rest or walking around. Then do 10 wall pushups or traditional pushups followed by 90 seconds of rest or walking around. And finally do 10 hip bridges, followed by 90 seconds of rest or walking around. Repeat the circuit until you have exercised about 40 to 45 minutes.
• Strength training workout: You also can transform a basic strength training circuit into a LIIT workout. For instance, do 10 kettlebell swings followed by a 90 second rest. Then, do 10 dumbbell curls, followed by a 90-second rest. Then, do 10 overhead presses, followed by a 90-second rest. And finally do 10 lateral raises, followed by a 90-second rest.

How to Add LIIT to Your Workout Routine

It's relatively simple to add LIIT to your workouts if you just focus on varying your speed and your intensity. In other words, if you typically go for a 30 minute walk, you can change it into a LIIT workout by adding bursts of intensity. Start out walking at your normal pace, and then increase your speed for 90 seconds, then return to your normal pace for three to four minutes. You can ensure it is a LIIT workout (and not HIIT) by monitoring your heart rate and making sure you are not taxing your heart too much.

You also can use the concept of progressive overload—which means you gradually increase the weight you lift or the distance you walk or run to make your workouts more challenging. This allows you to get stronger over time without overtaxing your body. One example of progressive overload in strength training involves adding more repetitions or sets as you progress and get stronger. It also can be accomplished using varying levels of intensity.

Using progressive overload is way to ensure your body continues to get stronger by consistently challenging yourself with quicker steps, increasing weights, or adding more reps. Doing these things encourages your body to keep improving, but at a lower intensity.

Benefits of LIIT

There are a number of benefits to incorporating a LIIT into your workout regimen, from a reduced risk of injury to simple incorporation into your routine.

Provides an Accessible Workout for Variety of Fitness Levels

Low intensity exercise like what is found in a LIIT workout is both accessible and safe for a variety of different types of exercisers, according to researchers in one study. In fact, they note that exercising at a low intensity is safe for pregnant people, exercise beginners, older adults and even people with heart issues, because of the very low likelihood for muscle injuries and cardiometabolic risk (or heart-related issues).

Produces Similar Results to High Intensity Workouts

There is some evidence that you can get the same health benefits from low intensity workouts that you can from high intensity workouts. In fact, one study found that regardless of whether study participants exercised at a high intensity or a low intensity, they experience the same reductions of abdominal obesity, suggesting that exercise is effective regardless of the intensity.

Offers Physical and Cognitive Benefits Especially for Older Adults

Researchers in one study found that low intensity exercise also can provide a host of physical and cognitive benefits, especially for older adults. They also noted that older people also tend to stick with low intensity exercise when compared to higher intensity exercises—which can be more challenging to do and taxing on the body. Low intensity exercise may be particularly beneficial for adults who are frail and at risk for injury.

Adds Balance to a Workout Regimen

Exercise experts note that too much of one type of exercise—such as HIIT workouts–can be taxing on the body and lead to fatigue, burnout, and injuries. For this reason, many experts recommend incorporating low impact or low intensity exercises to your workout regimen rather than just focusing on high intensity workouts. By balancing your high intensity workouts with other types of less-stressful exercise, you allow your body time to fully recover and adapt. What's more, low intensity workouts improve mobility rather than simply working on muscle development—so there is a need for both forms of exercise.

Potential Downsides and Considerations

While there are very few risks with LIIT, there are some drawbacks to this approach to exercise. For instance, one of its advantages—being a lower intensity exercise—is also one of its disadvantages. Because the focus of LIIT is to go at a lower intensity—and put less stress on the heart—it can take longer to see results, especially in comparison to HIIT workouts.

For instance, research shows HIIT workouts can improve your cardiovascular fitness and heart health in 40% less training time than lower intensity exercises. So, not only do you need to workout longer with LIIT, but it also may take you a little longer to see the results of your efforts.

If you want to see the same results that you might with HIIT, then you have to spend more time working out, which can be a real downside for people who are pressed for time. In other words what you can accomplish in 20 to 30 minutes with a HIIT workout, will take you 40 to 60 minutes with LIIT. This time commitment can impact the sustainability of LIIT workouts—despite the ease with which you can incorporate it into your everyday workout regimen.

A Quick Review

LIIT is a low impact interval workout that is less intense than a HIIT workout but still provides your body with health benefits. During a LIIT workout, you can expect to work moderately hard or at about 50% to 70% of your maximum heart rate. Just about any low intensity exercise can be incorporated into a LIIT workout. These workouts may not have the immediate impact that a HIIT workout provides, but over the long term, you can still accomplish your fitness goals.

LIIT workouts are ideal for older people, those new to exercise, and those recovering from an injury who are looking for a low impact way to exercise without putting too much stress on their body.