Getting back to the effects of exercise in general, a number of biological effects occur when you work out. This includes changes in your: Muscles, which use glucose and ATP for contraction and movement. To create more ATP, your body needs extra oxygen, so breathing increases and your heart starts pumping more blood to your muscles. Without sufficient oxygen, lactic acid will form instead. Tiny tears in your muscles make them grow bigger and stronger as they heal. Lungs.
As your muscles call for more oxygen (as much as 15 times more oxygen than when you’re at rest), your breathing rate increases. Once the muscles surrounding your lungs cannot move any faster, you’ve reached what’s called your VO2 max—your maximum capacity of oxygen use. The higher your VO2 max, the fitter you are. Heart. As mentioned, your heart rate increases with physical activity to supply more oxygenated blood to…
