Fitness Articles

Reference Guide to Anaerobic Exercise

An In-Depth Look at High Intensity Exercise

SparkPeople’s Exercise Reference Guides offer an in-depth look at the principles of fitness.

We often hear a lot about aerobic or “cardio” exercise and how it improves fitness, reduces one’s risk of lifestyle diseases, and helps with weight management. What we hear much less about is another type of cardiovascular exercise known as anaerobic exercise.

What is Anaerobic Exercise?
While “aerobic” means “with oxygen,” anaerobic means “without air" or "without oxygen." Anaerobic exercise is short-lasting, high-intensity activity, where your body’s demand for oxygen exceeds the oxygen supply available. Anaerobic exercise relies on energy sources that are stored in the muscles and, unlike aerobic exercise, is not dependent on oxygen from (breathing) the air. Examples of anaerobic exercise include: heavy weight-lifting, all types of sprints (running, biking, etc.), jumping rope, hill climbing, interval training, isometrics, or any rapid burst of hard exercise.

What are the Benefits of Anaerobic Exercise?
Anaerobic exercise uses your muscles at a high intensity for a short period of time. As a result, it can help:
  • Develop stronger muscles
  • Improve your VO2 max (the highest amount of oxygen one can consume during exercise) and thus improve your cardio-respiratory fitness
  • Increase your capacity to withstand the buildup of waste substances (such as lactic acid) and remove them from the body. This means your endurance and ability to fight fatigue will improve.
Overall, anaerobic exercise burns fewer calories than does aerobic exercise and may be somewhat less beneficial for cardiovascular fitness. However, it is better at building strength and muscle mass and still benefits the heart and lungs. In the long run, increased muscle mass helps a person become leaner and manage his weight, because muscle uses large amounts of calories.

How Does Anaerobic Exercise Work?
When you begin to work out vigorously, there is a temporary shortage of oxygen being delivered to the working muscles. Lactic acid is a by-product of producing energy anaerobically. When lactic acid accumulates at high levels in the blood, it causes muscular fatigue. This is why anaerobic exercises cannot last very long.

But with training, the body becomes better equipped to handle lactic acid. Several efficient changes occur that result in decreased production of lactic acid and increased removal of it from the bloodstream. The body also produces “buffers” that delay the onset of fatigue during anaerobic exercise. Studies have shown that with anaerobic training, the muscle’s buffering capacity is increased by 12% to 50%. With this increased buffering capacity, more lactic acid can accumulate during high intensity exercise without causing fatigue.
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About The Author

Jen Mueller Jen Mueller
Jen received her master's degree in health promotion and education from the University of Cincinnati. A mom and avid marathon runner, she is an ACE-certified personal trainer, health coach, medical exercise specialist and behavior change specialist. See all of Jen's articles.

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