Why do you get short of breath in a race?

Answer 1

You can move because your muscles respire, this involves using glucose and oxygen and turning it into water and energy. The more you move your muscles, the more oxygen you need.

Oxygen has to go into the lungs then pass into the bloodstream to get to all your muscles. This process is limited so when you use your muscles a lot when running you begin to run out of oxygen. Your body compensates by performing more anaerobic respiration, which doesn't need oxygen. This produces lactic acid but allows you to keep running. The lack of oxygen is called oxygen debt, the faster and the more you run, the more oxygen debt builds up.

When you stop running there is still all that lactic acid in your bloodstream and in your muscles. You need to keep breathing so your body can neutralise that acid otherwise your muscles would end up damaged.

Answer 2

your muscles use up a lot of oxygen so you have to breath in a lot to get more. if you are talking about unnaturally/unhaelthily short breath then i suggest you talk to your doctor before you hurt/kill yourself

Answer 3

When you exercise, your muscles, heart and other vital tissues require more oxygen to function normally. Your heart beats faster, it pumps more blood throughout the body. The oxygen in this blood is supplied to all the organs and oxygen poor blood returns to the lungs at an increased rate. As more oxygen is needed to enrich this fast moving blood, we breathe faster. This is why we become breathless after exercise.