Chances are, you’re familiar with aerobic exercise, exercise that raises your heart rate long enough to improve cardiovascular health and fitness. But there’s another type of training called anaerobic exercise that also offers health benefits. You might wonder how these two forms of training differ and whether one is better than the other in terms of improving your fitness level. Let’s look at each type of training in more detail.
Aerobic Training
Aerobic literally means “with oxygen.” When you do an aerobic workout, your heart rate increases and your blood vessels open wider to deliver more oxygen to the tissues that need it. During aerobic exercise, requirements for oxygen go up, and, in response to training, your body becomes more efficient at supplying oxygen to the tissues that demand it. In other words, your body adapts and your aerobic capacity, or V02 max, increases.
Some of the changes that happen as your body adapts to aerobic exercise:
. Hemoglobin increases for better oxygen delivery
. Your heart becomes a more efficient pump (increase in stroke volume)
. Capillary supply to muscle cells go up for better delivery of blood and oxygen
. The number of mitochondria in muscle cells increase in number for more production of ATP
After several weeks of aerobic training, you may notice a drop in resting heart rate as your cardiovascular system becomes a more efficient oxygen delivery system.
What type of exercise constitutes aerobic training? Cycling, jogging, using an elliptical machine, or rowing machine at a moderate intensity, usually for 30 minutes or more are all candidates. Aerobic exercise primarily works slow-twitch muscle fibers, those that can’t generate lots of force but are resistant to fatigue. When you run a marathon, you depend mainly on slow-twitch muscle fibers to get you over the finish line.
Anaerobic Training
In contrast to aerobics, anaerobic means literally “without oxygen.” During anaerobic exercise, you’re working out at such a vigorous pace that aerobic energy systems can’t meet the demand for energy since they’re so slow. Instead, the phosphagen system and anaerobic pathways supply the ATP your muscles need to sustain exercise. Unfortunately, these systems “poop out” quickly. The phosphagen system, by itself, can fuel exercise for only 10 to 15 seconds. The secondary anaerobic pathway can sustain exercise for between 30 seconds and 3 minutes.
The other way anaerobic training differs is the primary muscle fiber type you’re using. During anaerobic activity, you recruit mainly fast-twitch muscle fibers, those designed to generate high levels of force. Unfortunately, they can’t sustain the force they generate for very long, usually only a few seconds up to a minute or so.
What types of activities are anaerobic? Intense weight training, sprinting, fast rope jumping, plyometrics, and high-intensity interval training are all anaerobic activities. These types of exercise require near maximal effort and you can’t sustain them very long. After a certain period of time, lactic acid begins to build up, the pH of your blood starts to drop, your muscles start to burn, and you really suck wind.
How Do You Know When You’re Exercising Anaerobically?
One way to determine whether you’re training aerobically or anaerobically is the “talk test.” If you’re in the aerobic zone, you should be able to talk, but singing is too difficult. If you’re able to comfortably sing, you’re not working hard enough. During anaerobic exercise, you breathe at such a high rate that singing AND talking should be difficult. You know you’re in the anaerobic zone when you can only manage to say a few words without gasping for air.
What Are the Benefits of Anaerobic Exercise?
We already know the benefits of aerobic training – it burns calories and improves your cardiovascular health. What about anaerobic exercise? Anaerobic exercise, too, due to its intensity, enhances cardiovascular fitness. In addition, it has benefits that aerobic exercise doesn’t.
Anaerobic exercise increases your lactic acid threshold, your body’s ability to tolerate the build-up of lactic acid and acidity and to buffer and eliminate it. Running a marathon mostly uses aerobic energy production, but the final sprint you do at the end, to cross the finish line, is anaerobic. In addition, anaerobic exercise, by working fast-twitch muscle fibers, enhances strength and power.
Because you can’t sustain anaerobic exercise for long, the best way to get the benefits is with interval training, alternating intervals of high-intensity, anaerobic exercise followed by recovery intervals. The recovery interval allows you to partially recover so you can work at a high intensity during the next active interval. When you do a high-intensity interval workout, you typically do a shorter workout, due to the higher demand on your body.
When you calculate the calorie burn DURING a HIIT workout, it might be less than what you would burn doing moderate-intensity exercise for a longer period of time, BUT anaerobic exercise creates a greater “afterburn” or EPOC, meaning your body burns more calories for 24 hours or longer after an anaerobic workout. According to some studies, HIIT training is more effective for fat reduction and for losing belly fat too.
Anaerobic exercise also leads to a greater release of fat-burning hormones, like catecholamines and growth hormone, which helps you get leaner. That’s why you shouldn’t judge the benefits of a workout by duration but more by intensity. Entering the anaerobic zone clearly has benefits.
The Bottom Line
Now you know the difference between aerobic and anaerobic exercise. As you can see, they both offer benefits, one develops endurance and the other strength and power. Both can improve cardiovascular fitness. There’s no reason why you must choose one over the other. You might do a HIIT routine where you enter the anaerobic zone during one session and do lighter cardio that mainly taps aerobic pathways in another. On the other hand, if you have specific fitness goals, for example, you want to get stronger or more powerful, it makes more sense to do more anaerobic exercise since adaptations to exercise are specific. Think about your goals and plan accordingly.
References:
ACE Fitness. “Slow-Twitch versus Fast-Twitch Muscle Fibers”
Int J Obes (Lond). 2008 Apr;32(4):684-91. doi: 10.1038/sj.ijo.0803781. Epub 2008 Jan 15.
Poloquin Group. “Is Aerobic or Anaerobic Training Best for Getting Rid of Belly Fat?”
J Obes. 2011; 2011: 868305.
Med Sci Sports Exerc. 2008 Nov;40(11):1863-72. doi: 10.1249/MSS.0b013e3181801d40
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