HIIT vs MICT vs LISS: What's the Difference? Which is Best for You?
Sep 23, 2021
What are HIIT, MICT, and LISS
HIIT stands for high intensity interval training and it consists of very intense (as high as 80%+ of max heart rate) anaerobic bouts of exercise followed by medium intensity (50-60% max heart rate) aerobic bouts of exercise. HIIT workouts are generally shorter than the workouts of their cardio counterparts, lasting only 20-30 minutes in most cases. HIIT training often utilizes sprints, resistance training, or other high intensity modalities.
MICT stands for medium intensity continuous training and consists of moderate difficulty aerobic exercise like jogging, cycling, or pick-up sports. MICT workouts are normally 30 minutes to an hour.
Lastly, LISS stands for low intensity steady-state and consists of easier exercises like walking or light hiking. LISS workouts can be any duration but are most often the longest of the three, lasting up to an hour or longer.
Pros and Cons of HIIT
A recent meta-analysis of the benefits of HIIT found that it is the most effective type of exercise for increasing vo2 max and endothelial function (Mattioni 2021). Basically, it is great at increasing the body's ability to consume, deliver, and utilize oxygen where it is needed. These factors make HIIT an especially potent tool when training for activities where conditioning is important. Since HIIT workouts are shorter, arguably its biggest benefit is that it's more time efficient than the other types of cardio. An intangible benefit of HIIT is that its fast pace and variety keeps it exciting to perform day to day. HIIT also comes with some clearly defined cons. Because it is so intense, HIIT can be beyond an individual's personal capabilities. It is also notably harder to recover from when compared to the other types of cardio, by extent, increasing the risk of injury.
If you’ve read about HIIT online, you may have heard about the calorie burning effects of something called EPOC (Excess Post-exercise Oxygen Consumption). New research shows that EPOC only accounts for, if anything, 0-10% of total calories burned during a HIIT session (Keating 2017). Therefore, EPOC is not a substantial contributor to weight loss and HIIT should not be chosen over other forms of cardio solely because of EPOC.
Pros and Cons of MICT/LISS
The pros and cons of MICT and LISS are very similar and so they will be grouped together. One big pro for MICT/LISS is that these types of cardio have been shown to be most effective for maintaining healthy blood sugar levels and long term glycemic control (Mattioni 2021). Because of their low impact, they are also very easy to recover from and thus can be incorporated every single day as part of a healthy exercise regime. An intangible benefit of these types of long form cardio is that they can be a time to think, listen to music or podcasts, and take in the world around you without having to focus on a complex/intense workout. The only real downside to MICT or LISS is that they can often be time consuming, requiring a time commitment.
Changing body composition, or the portion of lean body mass compared to fat mass, is one of the most sought after benefits of performing cardio. Ultimately the only way to lose weight is by being in a calorie deficit (use more energy in a day than you consume from food/drink). When it comes to choosing a form of cardio as a weight loss tool, they can all be effective. A pound of feathers weighs the same as a pound of bricks and burning 100 calories doing HIIT is the same as burning 100 calories doing MICT or LISS. Thus, there is no significant benefit to body composition gained by choosing one form of cardio over another (Mattioni 2021). In addition, cardio is only one piece of the equation and should be paired with dietary intervention for most optimal weight change results. You can take a look at this with a Fitness Together nutrition coach!
While each type of cardio is a little different, the biggest driver of results is adherence to a consistent plan! Choose a cardio type that is fun and works for you and your goals. You can even mix a bit of everything!
Mattioni Maturana, Felipe et al. “Effectiveness of HIIE versus MICT in Improving Cardiometabolic Risk Factors in Health and Disease: A Meta-analysis.” Medicine and science in sports and exercise vol. 53,3 (2021): 559-573.
Keating, S E et al. “A systematic review and meta-analysis of interval training versus moderate-intensity continuous training on body adiposity.” Obesity reviews : an official journal of the International Association for the Study of Obesity vol. 18,8 (2017): 943-964.