Which cardio workout burns more fat: interval or low intensity?

What is low intensity cardio?

Moderate pace in any aerobic exercise (running, swimming, elliptical trainer, stepper, exercise bike, bicycle, etc.). Low-intensity cardio is characterized by an average heart rate that allows you to breathe fully without a pronounced feeling of shortness of breath or oxygen debt.

What is interval cardio?

Alternating intensity is a distinctive feature of this type of training. A striking example is sprint/walk in the 15/45 format: 15 seconds of sprinting are followed by 45 seconds of walking or slow running. Such “circles” are repeated several times – this is the basic concept of interval cardio.

The essence of the dispute

The fitness world is divided into two camps: some argue that interval training is more effective, as it burns more calories per unit of time and promotes weight loss due to the post-metabolic effect. The other camp assures us of the effectiveness of low-intensity cardio, which has been practiced by fitness and bodybuilding athletes for over 50 years.

Each group talks about its pros and cons. There is a lot of information, and beginners simply get lost in it. However, the modern trend for fast CrossFit workouts has brought interval cardio forward, but is there a clear leader here?

Biochemistry and Calorie Expenditure

Scientists recently checked how many calories a person burns during interval, aerobic and strength training. This data will form the basis of our article. Links to the studies will be at the end.

A standard aerobic cardio session, such as a leisurely run, burns 5-10 kcal/min. This rule is valid for beginners and amateurs. An experienced and professional runner can burn 20 kcal/min, but they are a minority, so let's take the first example.

A standard interval cardio session burns an average of 10 kcal/min. More details: 1 minute of high intensity and 1 minute of rest. During the first minute you burn 15 kcal/min, and during the rest period 5 kcal/min, which gives an average of 10 kcal per minute.

Metabolic response or EPOC

Excess Post Oxygen Consumption – the effect of burning fat after finishing a workout due to excess oxygen, restoration of energy metabolism and oxygen debt. It is inherent in any physical activity.

EPOC for low intensity cardio – 7%
EPOC for high intensity cardio – 14%
The effect of intervals is 2 times greater, but this is not a serious argument in favor of superiority. It is enough to look at the situation from the point of view of practice.

Practical Comparison of Cardio Workouts

10 minutes of low intensity cardio = 100 kcal + 7% EPOC = 107 kcal
30 minutes of low intensity cardio = 300 kcal + 7% EPOC = 321 kcal
60 minutes of low intensity cardio = 600 kcal + 7% EPOC = 642 kcal
Now let's compare these figures with high-intensity interval training. It's extremely difficult to complete a 30-minute session in this format, but it's doable, so let's imagine a half-hour workout:

30 minutes of interval cardio = 300 kcal + 14% EPOC = 342 kcal
60 minutes of interval cardio = 600 kcal + 14% EPOC = 684 kcal
As you can see, the difference in calorie expenditure is insignificant, despite the 14% EPOC. Do not forget that 30-minute interval training is difficult for many, and 60 minutes is within the power of only a few. But you should not make categorical conclusions.

Both types of cardio training are good in the context of weight loss. The goal of training is to burn calories and stimulate the daily energy deficit. The process should be comfortable, and for some athletes, running 25 minutes of intervals is easier than spending an hour on a treadmill. Others, on the contrary, are more comfortable doing low-intensity, calm cardio without excessive shortness of breath.

About Strength Training and EPOC

Strength training is a variation of interval training, because you do a set and rest. The only difference is the duration of rest and time under load. In general, EPOC after strength training is 14%. Recall that strength training burns 7-9 kcal per minute, but this figure is influenced by several factors at once.

The body's metabolic and hormonal response to strength training is not much different from interval or aerobic cardio. So in terms of calorie expenditure and weight loss, there is no significant difference between the two workouts.

What to choose?

Interval training has become fashionable due to the relatively short duration of training in this format. Run for 20-25 minutes and you are free with 14% EPOC. However, regular and too frequent repetition of this type of training inevitably leads to overtraining due to overload of the central nervous system. Therefore, interval cardio is prescribed in doses, for example, once a week in the presence of strength training (2-3 times).

Low-intensity cardio requires more time. It is difficult to perform due to monotony and boredom, but you can burn more calories, since the duration of a cardio session can be from 50 to 60 minutes. What is equally important is that you can train in this format often, since aerobic cardio practically does not load the central nervous system.

Therefore, against the background of strength training, they choose not interval cardio, but regular - low-intensity. Feel free to put cardio on non-strength days, and do not be afraid of overtraining.

Style Summary

Don't look for magical fat-burning workouts. High or low intensity - it doesn't matter. What matters is creating a calorie deficit, and any type of exercise is suitable for this task.

Choose what you like. This approach will allow you to follow the chosen training plan longer, as a result of which you will lose weight without breakdowns and pauses.

Instead of trying to figure out which type of cardio is more effective, combine all of its types. At the beginning of the week, try an aerobic run, in the middle – a strength workout, and on the weekend – an interval workout, which does not require much time. Variety is the key to success in losing weight, and not only in your diet, but also in your workouts.