Is aerobic or anaerobic exercise better for fat loss? Is there a place for both? Let’s take a look at what aerobic and anaerobic exercise are and then find out the best way to structure our exercise program for max fat loss.
Aerobic exercise is exercise that is typically lower in intensity and is done for a long duration. Aerobic exercise primarily uses fat for energy. Some of these aerobic exercises are activities such as walking, light jogging, bicycling, or using the elliptical machine.
Now, some of these can certainly be used for high-intensity exercise if you push yourself hard enough, but more times than not, they are used for staying in your fat-burning zone.
Anaerobic exercise is typically high intensity and is done for short bursts of time. The primary fuel source for anaerobic exercise is glycogen, which is manufactured from glucose.
When exercising in your anaerobic zone, your body is unable to break down fatty acids fast enough to fuel your workout. Instead, it uses muscle glycogen and ATP stores as the primary fuel source.
A few examples of high-intensity exercise are weight training, sprinting, and rowing. There is much more to understand about these two exercise types, but for now, let’s work with what we have.
Aerobic vs Anaerobic Exercise
The whole idea behind the fat-burning zone is that if you exercise at a particular heart rate (around 60-70%), you will burn a higher percentage of calories from fat. This is true. You might be asking then why is this no good if I’m trying to lose fat?
The answer is quite simple. The lower your heart rate, the higher the percentage of calories burned will come from fat. The key to this sentence is “higher the percentage“.
You actually burn the highest percentage of calories from fat while you sleep! Your heart rate is at its lowest at that time. So in theory, if you believe in the fat-burning zone for the best fat loss, you should instead try to sleep the fat away. You do after all burn a higher percentage of calories from fat.
The problem with this thinking is that while you burn a higher percentage of calories from fat, the total number of calories burned is lower. Much lower. Even though high-intensity exercise burns a lower percentage of fat during your workout, it burns more total calories.
The important thing to remember during exercise is to try and burn calories. More calories burned equals more fat lost. Exercise is best used to create a favorable metabolic environment so that your nutrition can take off the fat, and nothing does this better than high-intensity exercise.
And if you still aren’t convinced, think of it this way: Do you really think that the people who don’t work out as hard are going to lose more fat than the people who bust their butts and do high-intensity sprints?
When is Aerobic Exercise Beneficial?
Now, I don’t want to be that guy who demonizes low-intensity exercise. There is a time and a place for everything. So in what scenario should you do aerobic exercise?
The issue with high-intensity exercise is that it is very demanding on your muscles and central nervous system. This makes it difficult to work out at a high intensity for long periods of time or on consecutive days.
Since we still want to burn extra calories, this is the opportune time to implement some low-intensity exercise. An hour walk will burn 300-400 calories, and this can make a big difference in your weight loss. Try squeezing 1-3 lower-intensity cardio days in between your strength training sessions and see the positive impact the extra activity makes.
Two other times when low-intensity exercise is preferable is when you’re injured or if your body can’t handle the impact high-intensity exercise brings with it. In this case it would be best to build your intensity up over time to let your body and joints adjust.
The moral of the story? If you can do high-intensity exercise – do it. Make it a priority. Study after study shows it to be more beneficial for fat loss. If you’ve maxed out the number of days you can do high-intensity exercise but you still need some extra calories burned, then squeeze in a few sessions of low-intensity exercise.
In the end it’s about energy balance, and you should aim to create your calorie deficit in the most efficient way possible.