HIIT vs. LISS: Which is the best form of Cardio?

HIIT vs. LISS: Which is the best form of Cardio?

Which type of cardio is better, HIIT or LISS?

Which type of cardio is better, HIIT or LISS?

This is a hot topic in the fitness industry and can leave friends and gyms alike divided over their favorite type of cardio.

But which one is more effective? In this blog, we will compare the two and their efficacy, providing you with an answer to whether HIIT or LISS is the best type of cardio.

The Goal of Cardio Exercise

To accurately compare these two types of exercise, we need first to establish why we do cardio.

Cardio is short for cardiovascular and refers to exercise that works the body’s aerobic system. Therefore, when you are doing cardio, you are exercising your aerobic system.

The aerobic system is our main source of energy. It controls how well our body can use oxygen to fuel activity.

To determine whether HIIT or LISS is the best form of cardio, we will look at how well they build the aerobic system.

Some easily observed characteristics of a well built aerobic system are good endurance and the ability to pace oneself for a set duration of work.

High Intensity Interval Training (HIIT)

HIIT is a style of exercising that focuses on high levels of effort for a short amount of time, followed by a period of rest, repeated for a certain number of intervals. It claims to build the aerobic system faster than any other methodology.

However, HITT instead challenges the anaerobic lactic energy system and does not build a broad base of aerobic capacity. Anaerobic training is highly stressful, and while you will see adaptations (results) very quickly,  you can only maintain this type of highly stressful work for so long. After a short while, the body will stop adapting, and results will halt.

Example HIIT Cardio Workout:

Run on the treadmill for 10 minutes:

30 seconds all out

30 seconds off

Result: Power dropped off each interval and could not be maintained.

Low Intensity Steady State (LISS)

LISS refers to a style of training that focuses on low intensity effort for an extended time. This is the traditional method of cardio, and examples include long walks, hikes, bikes, and runs.

This type of training is lower stress than HITT. It works because it slowly exposes the body to stimulus. This sustainable approach gives the body time to build adaptation in the cardiovascular system.

To see the best results from LISS, you need to follow a long slow progression. But while this takes longer, the performance peak you can reach is much higher and more sustainable than HIIT.

Example LISS Cardio Workout:

45 minute As Many Rounds as Possible at a sustained pace

200m Ski Erg

400m Row

600m Assault Bike

Result: Power output remained steady and sustainable across the entire 45 minutes.

HIIT vs. LISS: Which is the Better Form of Cardio?

Which is the better form of cardio?

When we compare these two types of exercise to our definition of a well built aerobic system, it is clear that LISS is the superior form of cardio. 

It is superior because the long slow pace of these workouts teaches the body how to pace itself. Also, the slow progression lets the aerobic system reach a higher peak than the short, intense spike from HIIT. Over time, you may build to faster aerobic intervals, but not without starting with LISS.

HIIT can still build the aerobic system, but it will not be as effective. The fast intervals do not teach the body how to pace, and their short duration is no substitute for the volume that LISS provides.

Learn How to Create Progressions for Both Energy Systems

The fitness industry is confusing.

Every month there seems to be a study preaching a new way to build the aerobic system. With all this information, it can be tough to separate fitness fact from fad.

Thankfully, there are some time-tested principles you can use to build you or your client’s aerobic system to a level unattainable from HIIT training alone.

Learn these principles and how to program for the body’s three main energy systems in our free guide How to Program and Progress Energy System Training.

Download now and start creating progressions that get real results.


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