Aerobic Exercise
Aerobic and Anaerobic Exercise: What's the Difference?
You hear it all the time. Some fitness experts tell you to focus on aerobic exercise in order to burn fat while others tell you to work on building muscle (anaerobic exercise) because muscle burns more calories. Which is right?
What is Aerobic exercise? How does it differ from Anaerobic exercise? Is one better than the other? This is what we'll cover in this section.
Two Ways to Exercise
Most people assume that the terms aerobic and anaerobic refer to a specific type of exercise or to a specific exercise program (like "step aerobics" for example). This is not the case at all. Depending on how long and how hard you exercise (your duration and intensity), almost any kind of exercise can be performed in one of two ways: as Aerobic or as Anaerobic exercise.
When you exercise aerobically, you start out slow and increase your effort steadily. This slow pace allows your body to keep your muscles supplied with a steady stream of fuel and oxygen. When you exercise aerobically, you place an increasing demand on your cardio system forcing your heart and lungs to become stronger - one of the main goals of exercising this way.
In contrast to building slowly, anaerobic methods require a concentrated burst of intense power that forces your body to rely on fuel that's already present in the muscle, which is why most anaerobic exercise can't be performed at high intensity for more than a minute or two. Your muscles simply run out of stored energy and you usually have to slow down or stop altogether. When you exercise anaerobically, you force your muscles to repeatedly work against some sort of resistance. This builds strength in addition to increasing muscle size and tone -- the main benefits of anaerobic exercise.
Aerobic Exercise Facts
The word “Aerobic” literally means “with oxygen” and it's used to describe the type of metabolism, or energy conversion, that occurs in your body when you perform moderately paced exercises like walking, stretching, or cycling. When the body uses aerobic metabolism, it creates energy (technically known as Adenosine Triphosphate or “ATP“) using mostly fat as a fuel source. This is where the claim that “aerobic exercises burn fat” comes from.
What?! An exercise method that burns mostly fat? Isn't that what we're all looking for? Yes, but as you'll see later, this is only half the story.
What About Anaerobic Exercise?
The term “Anaerobic” means “without oxygen” and is used to describe a different type of energy conversion that occurs when your muscles need a quick burst of energy. To provide this quick burst, the body anaerobically metabolizes locally stored muscle glycogen, which is a form of stored glucose, into ATP. Since glucose is a simple sugar, or carbohydrate, this is the basis for the claim that "anaerobic exercises burn mostly carbs.”
Although anaerobic metabolism is not as efficient as aerobic metabolism at converting energy, it’s the fastest way for the body to provide ATP to the muscles on short notice since it uses fuel that's already stored in the muscle. This is exactly the burst of energy that you need when running sprints, or jumping, or performing any other action where you have to go all out in intensity.
Another benefit is that anaerobic exercise tends to build and increase muscle mass. Muscle tissue is more metabolically active and burns an average of 40-50 more calories per pound than other types of tissue, even while at rest. This is where the statement that “building muscle increases your metabolism and burns calories even while you rest” comes from.
Aerobic or Anaerobic: Which is the Best?
So which method is best? Why is it that one fitness guru will recommend one method and another fitness guru another? Well, one reason is that many fitness trainers only take one or two of the facts listed above (for example, "aerobics burn fat") and tend to disregard the rest. They then base an entire exercise program around this incomplete information and promote it as the “ultimate fitness answer.” However, in real life, things are never that simple. The honest truth is that you need both. You really can't separate one method from the other because they both interact with and affect each other.
For example:
- Most exercises produce both aerobic and anaerobic metabolism. For example, most people think of a step class as all “aerobic” and it does build heart and lung capacity. However, the simple act of moving and lifting your arms and legs also builds strength and endurance - a benefit of anaerobic exercise. Lifting weights is primarily anaerobic, but it also requires you to breathe properly, an aerobic activity.
- The fact that aerobic exercise burns fat is true only if it’s done within a specific range of intensity. Increase the intensity and you begin to burn carbs (anaerobic metabolism).
- Building muscle raises your metabolic rate and burns more calories. But if you don't have a good aerobic base, you won't be able to perform enough anaerobic exercise to actually build muscle.
See the problem? Each one is really part of the other! So asking what type of exercise method is more effective, aerobic or anaerobic, is like asking which part of a car is really necessary: the engine, or the wheels? The answer is that if you really want to get anywhere, you need both!
So what's the balanced way to exercise? Use a routine that incorporates both aerobic and anaerobic methods. Your fitness program should alternate between exercises that target first one method followed by the other. For example, some stretching as a warm up (aerobic), followed by a stationary bike or elliptical trainer (aerobic and anaerobic), followed by some weight machines (anaerobic), followed by some brisk walking or a dance class (aerobic and anaerobic), followed by more stretching as your cool down (aerobic). You get the idea.
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