Question: During exercise why do we get out of breath?

Jessica Mitchell answered on 14 Nov 2019:

When we exercise our muscles need more oxygen to keep us moving or to give us enough power to life heavy weights. This means we need to breath more often or more deeply to bring in oxygen and also get rid of carbon dioxide (the waste product of our breathing mechanism). Our heart also has to beat faster to move this oxygen around the body and get it to our muscles – this causes our breathing to become faster. As you get fitter you will notice you can do the same amount of exercise without getting as out of breath, and by keeping your heart rate lower – this is good way to measure your progress.