Cardiovascular exercise refers to any type of exercise that keeps your heart rate elevated for a continuous length of time. Like any form of physical activity, cardiovascular exercise provides plenty of health benefits. There are studies showing cardio can improve heart health, bone health, brain function, and sleep.
But is it really necessary for individuals that want to burn fat? Also, does cardio impair muscle growth? In this article, I’ll give you an evidence-based answer to these questions.
Cardio and Fat Loss
Several scientific studies show that regularly doing cardio, without any form of caloric restriction, does not result in much fat loss. There’s also evidence showing you can gain fat if you just do cardio without considering any other variables. This is not because cardio is “fattening” or “harmful”, but because it often does not burn enough calories to put you in an “energy deficit.”
Fat loss is nothing more than an adaptation to an energy deficit. If you consume fewer calories than your body expends, your body has no choice but to burn fat. This is dictated by the ”Energy Balance”, which is supported by the law of thermodynamics.
The scientific law of thermodynamics shows that energy can’t be destroyed or created, only transformed. So, a surplus of energy has to be stored (fat gain) and an energy deficit needs to be “compensated” by internal reserves (fat loss).
You can choose to create an energy deficit by solely performing more cardio, but it’s nearly impossible to burn an extra 500-1000 calories a day without, basically, burning yourself out. That’s why caloric restriction is required during a fat loss phase.
That said, this does not mean cardio is useless for fat loss. Substantially lowering caloric intake may be a huge transition for some and it’ll leave them with very little calories to work with. This is especially true for people that already have a low “maintenance level.” If this is you, you are the type of person that benefits from cardio significantly.
Increasing your total energy expenditure by performing cardio regularly will allow you to consume more food while still being able to maintain an energy deficit for fat loss.
Later in this article, I’ll give you a free example cardio routine that will help you maximize the number of calories you burn during your cardio sessions.
Cardio and Muscle Growth
Like resistance training, cardio is a stress. Your body can only take on a certain amount of stress before it becomes chronic and starts interfering with recovery and muscle growth.
This brings us to what is known in Exercise Science as the “interference effect.” Combining cardio with resistance training can interfere with your muscle and strength gains and, therefore, hold you back from maximizing your muscular potential.
If you think about it, the interference effect is quite logical. You can’t experience optimal adaptations in 2 very different types of physical activity.
“You can’t be the world’s best sprinter and marathon runner at the same time.” – Menno Henselmans
So, one could argue that the more cardio you do, the less muscle and strength you will be able to gain. However, a cardio session or two is not detrimental to your gains. You will still be able to get away with some cardio without significantly impairing muscle and strength gains, as long as you do not perform cardio before your weightlifting sessions. A good rule of thumb is to not exceed 3 cardio sessions per week in a fat loss phase.
What Kind of Cardio?
Generally, we can distinct cardio into three categories.
- Low-intensity (think walking)
- Moderate-intensity (think jogging)
- High-intensity (think sprinting)
Considering we just want to increase energy expenditure, all types of cardio are effective. But some types are more time-efficient than others. As you can imagine, the higher the intensity, the more calories you burn per minute. Of course, you will have to put in more effort, but it’s worth it if you are looking to save time.
Also, the higher the intensity, the greater the effect on “excess post-exercise oxygen consumption” (EPOC). EPOC refers to the amount of oxygen required to bring your body back to its normal resting state. The higher EPOC is, the more calories you burn post-workout. Calories burned due to EPOC can be up to 37% of the total calories burned in your cardio session.
Based on the information provided above, my preferred way of doing cardio is high-intensity interval training (HIIT). It’s tough, but it takes very little time. In just 15 minutes you will be able to burn hundreds of calories.
At the end of this article, you will be able to download a free 15-minute HIIT routine. It’s worth to note that HIIT routines can be very taxing. So, it’s not something you should be doing every day.
Your Evidence-Based Answer
Should you do cardio?
Like many things in fitness, it depends.
Cardio in and of itself does not cause fat loss. If fat loss is your goal, cardio is not necessary. That said, increasing energy expenditure through cardio will allow you to consume more food while staying in an energy deficit. So, cardio definitely is helpful.
Perform 1-3 cardio sessions per week if you want to increase energy expenditure so you can consume more calories.
If creating an energy deficit solely through lowering caloric intake is more enjoyable for you, that’s great too.
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