Anaerobic training is known as training without oxygen and you can only do it for short periods. Whereas aerobic training relies on your oxygen intake, anaerobic exercise is the opposite. It’s exercise with short, intense bursts of activity during which your body burns fuel faster than it can take in oxygen. A good example is a hundred metre sprint, where sprinters don’t appear to take a normal breath. Exercise becomes aerobic when its intensity decreases to a level that allows your body to take in oxygen. When you’re exercising, you typically use both. A four hundred-metre sprint will be ninety percent anaerobic, whereas a five-kilometre run will be mainly aerobic with about ten percent anaerobic work.