HIIT vs LISS

Which Is Best For Fat Loss And Fitness

By: Jeremy Fox, CNC, CPTUpdated: June 23, 2023

The debate about HIIT vs. LISS cardio can get heated. Some scream about intervals while others shout about steady state.

As a result, it can be difficult to figure out what kind of cardio is best for you. But the last thing you want is to waste your time doing something that doesn’t get results.

My goal is to facilitate a rational conversation about cardio exercise. And help you figure out how to get better fat loss and fitness results without wasted effort.

HIIT vs LISS

Exercise Intensity 101

Before we compare HIIT vs. LISS, let me briefly explain exercise intensity. First, high intensity and low intensity are defined by your heart rate. The more times your heart beats per minute (bpm), the higher the intensity.

Furthermore, exercise intensity is divided into five zones. Each zone represents a percentage of your maximum heart rate and corresponds to a particular training benefit.

Heart Rate Training Zones

Figure 1. Heart rate training zones.

As shown in Figure 1, your max heart rate decreases with age. And you can estimate your maximum by subtracting your age from 220.

For example, if you’re 30 years old, your max heart rate is around 190 beats per minute (220 – 30). From there, each zone is a percentage of 190 bpm.

With this information, you can adjust your training to get desired results. Now let’s get into what kind of training is best for fat loss and overall fitness.

HIIT vs LISS Comparision

HIIT (High-Intensity Interval Training) consists of short bursts of effort where you get close to your max heart rate—followed by slower recovery periods to get your heart rate back down. By comparison, LISS (Low-Intensity Steady State) is a constant pace at 50-70% of your max heart rate.

HIIT vs LISS for Fitness

Figure 2. HIIT vs LISS comparison of heart rate and duration. The example shows 20 minutes of HIIT with 5 intervals of 1 minute on and 2 minutes off. Compared to 30 minutes of steady state.

Generally, HIIT workouts are shorter in duration due to the taxing nature of max-effort exercise. On the other hand, LISS workouts can be sustained for long durations because they don’t take a significant toll on the body.

One advantage of HIIT is that your average heart rate is higher compared to LISS. As indicated by the dashed lines in Figure 2.

And a higher average heart rate means you burn more calories. In fact, HIIT burns 40-60% more calories per minute than LISS.

HIIT vs LISS Calories Burned Per Minute

Figure 3. Calories burned during exercise are directly proportional to the intensity of the exercise.

For instance, let’s compare the effects of 20 minutes of HIIT with 30 minutes of LISS. Both workouts burn 300 calories (20 minutes x 15 calories per minute = 300 calories and 30 minutes x 10 calories per minute = 300 calories).

However, to determine which workout is truly superior, we must examine the source of the calories instead of solely focusing on the calorie burn rate.

HIIT vs LISS for Fat Loss

While it’s true that HIIT burns more calories than LISS, it’s essential to know where those calories come from, specifically if you’re burning carbs or fat.

You see, higher-intensity exercise burns more calories from carbs. At the same time, lower-intensity exercise burns more calories from fat.

Fat vs Carbs Burned During Exercise

Figure 4. As exercise intensity increases, the calories burned from fat decrease.

Continuing our example, the HIIT workout only burns 90 calories from fat (30% of 300 calories). But the LISS workout burns 135 calories from fat (45% of 300 calories).

When calories per workout are the same, LISS burns about 50% more fat than HIIT.

Graphing calories burned from fat makes it easy to see how LISS burns more fat. At around 70% of your max heart rate, you hit the sweet spot for burning the most body fat per minute.

HIIT vs LISS Calories Burned From Fat

Figure 5. The curve results from multiplying calories burned per minute (Figure 3) by the % of calories from fat (Figure 4).

In addition to burning the maximum fat calories per minute, LISS lasts 30 minutes or more. Altogether, this means LISS has far more fat-burning potential than HIIT.

Use the table below to find your target heart rate for max fat burning. Find the age nearest yours at the top and follow it to the blue row to get your heart rate.

Or you can use my Cardio Calories Burned Calculator below.

Heart Rate Zones Table

Table 1. Estimated heart rates per training zone by age.

HIIT vs LISS Oxygen Consumption (EPOC)

But hold on; we’re not done yet! Proponents of HIIT argue that you burn more calories after high-intensity training. This is due to EPOC (Excess Post-Exercise Oxygen Consumption), also called the after-burn effect.

Simply put, you can’t get enough oxygen to replace what you use during intense exercise, creating an oxygen deficit. With an oxygen deficit, your respiratory rate increases for a particular duration after exercise, burning more calories.

Since EPOC is greater after HIIT than LISS, the thought is that you burn more calories while recovering.

HIIT vs LISS EPOC

Figure 6. Effect of Excess Post-Exercise Oxygen Consumption for HIIT vs LISS.

However, LISS consumes more oxygen during exercise compared to HIIT. So the 24-hour oxygen consumption (total green area) is pretty much the same for HIIT vs. LISS.

Indeed multiple studies show that the difference in 24-hour energy expenditure between HIIT and LISS is not statistically significant1,2,3,4. That means greater EPOC doesn’t necessarily mean more fat burning.

In summary, HIIT burns more calories per minute. But LISS generally burns more fat per minute. And the longer duration means you can burn significantly more fat with LISS.

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HIIT vs LISS for Fitness

For some people, the goal of cardio isn’t to burn as much fat as possible. You might use it to increase performance or train for a sport.

In that case, the assessment of HIIT vs. LISS is entirely different. So let’s find out which is better for overall fitness.

One way to assess fitness is by measuring power during sprint activities like running or cycling (peak performance). And another is measuring how fast your heart rate returns to normal after sprints (heart rate recovery).

HIIT vs LISS For Fitness

Figure 7. Percent improvement in peak performance and heart rate recovery for HIIT vs LISS protocols. Adapted from TL Stoggle et. al.5

In a 2017 study, researchers concluded that HIIT workouts resulted in a greater increase in peak performance. As well as a much larger improvement in heart rate recovery compared to LISS.

In addition, during HIIT workouts, your average heart rate is near the anaerobic threshold. This is the figurative line between medium intensity (aerobic) and high intensity (anaerobic).

In other words, it’s like running at your fastest mile pace – where you can’t push any harder without taking a break.

Effect of HIIT on Heart Rate Zones

Figure 8. Effect of HIIT on Heart Rate Zones

Training at the anaerobic threshold increases your ability to sustain higher heart rates for longer. So you are effectively moving your anaerobic threshold higher.

At the same time, regular bouts of max effort increase your maximum heart rate. For example, a 30-year-old can have a max heart rate of 200 bpm (equivalent to that of a 20-year-old). Thereby bumping up all your heart rate zones.

Most importantly, your fat-burning zone moves up too. That means you can do LISS at a higher heart rate and burn even more calories from fat!

In summary, HIIT is more effective than LISS for improving overall fitness. And it can even help you burn more fat during LISS.

HIIT vs LISS: Which Is Better

The HIIT vs. LISS debate has no “always” or “never” conclusion. Often, the best solution is a combination of both HIIT and LISS.

How much HIIT or LISS you do depends on your goals and preference. Finding the form of cardio exercise you enjoy is essential, so you’ll do it consistently.

Fat Burning Routine

For maximum fat loss, you should focus on LISS. While you don’t need HIIT to maximize fat loss, you can include it if you like more challenging workouts or to mix things up.

  • Aim for at least 150 minutes per week

  • Split it up into 3 to 6 LISS sessions, 30 to 60 minutes each

  • Target around 70% of your max HR

  • Examples: fast walking, slow jogging, cycling

  • Limit HIIT to 0 to 2 sessions per week

Fitness Routine

For optimal fitness, a mix of HIIT and LISS works best. Before doing HIIT workouts, ensure you’re healthy enough for max effort bouts. And include a 5-10 minute warm-up and cool down at 70% max HR.

  • Aim for at least 150 minutes per week

  • Split it up into 2 to 3 HIIT sessions, 10 to 20 minutes each

  • Target 90-100% max HR during intervals, with 30 sec to 3 min recovery periods

  • Examples: sprint/walk, row/rest, circuit training

  • Do LISS on days you don’t do HIIT

What About Resistance Training?

Resistance training consists of short bouts of anaerobic exercise separated by 30 seconds to 3 minutes of recovery. So, by definition, resistance training is a HIIT workout! At least when training hard enough to spike your heart rate during each set.

Not only does weight training build muscle, but it also burns a lot of calories and improves overall fitness. However, as with HIIT cardio, lifting weights is very taxing on your nervous system.

Therefore, it’s probably not a good idea to do a lot of HIIT cardio when you’re resistance training multiple days per week. Instead, save that intensity for the weight room and use LISS to burn fat.

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HIIT vs LISS Calculator

If you’re still not sure what your heart rate should be during your cardio sessions, don’t worry. I’ve got you covered with my Calorie Burn Calculator.

This calculator will show your target heart rate for each training zone. As well as how many total calories and “fat calories” you’ll burn.

Click here to learn more about how this calorie burn calculator works.

calorie burn calculator

Enter the information below to see your heart rate, calories burned, and fat burned. Easily adjust your workout to maximize fat burning!

HIIT vs LISS Final Thoughts

Both HIIT and LISS have their benefits, and each can be a valuable tool in your cardio toolbox.

LISS is best suited to burning fat without stressing your body too much. While HIIT is great for improving fitness or when you’re short on time.

Once again, the choice between HIIT and LISS depends on your goals and personal preference. I’ll leave you with this final graphic summarizing the pros and cons of each so you can decide which is best for you.

HIIT vs LISS Comparison

Stairmaster vs Treadmill

Exercise intensity is a big knob to turn when adjusting your cardio workout routine. And you also have multiple options for the form of cardio you do.

Two of the most popular cardio machines are the treadmill and the Stairmaster. But which one should you choose to maximize fat loss or fitness results?

To answer that, I put together the definitive guide to the Stairmaster vs treadmill. So you can determine which is best for your fitness goals.

Now you can apply these HIIT vs LISS principles in your next cardio workout and get better results for your effort. Check out my other great content or more practical fitness, nutrition, and supplement tips.

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By |June 23, 2023|Workouts|0 Comments
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