Exercise  increases the cardiovascular system's work rate or the build up of lactic acid due to anaerobic respiration. Regular exercise is an important part of a healthy lifestyle as it has many beneficial effects on the body. It helps you to control your weight; improves your cardiovascular fitness (the cardiovascular system comprises your heart and blood vessels) which means you have more stamina and are generally less tired; it strengthens your muscles and tendons; makes your bones tougher... and a lot more besides. When you are exercising, it has a number of physical effects on the... Show more

Exercise  increases the cardiovascular system's work rate or the build up of lactic acid due to anaerobic respiration.

Regular exercise is an important part of a healthy lifestyle as it has many beneficial effects on the body. It helps you to control your weight; improves your cardiovascular fitness (the cardiovascular system comprises your heart and blood vessels) which means you have more stamina and are generally less tired; it strengthens your muscles and tendons; makes your bones tougher... and a lot more besides.

When you are exercising, it has a number of physical effects on the body, all because of increased respiration as your muscle cells are working harder. Your body needs to make adjustments to meet this increased demand for oxygen and glucose by the respiring muscles.

You will first notice that your heart rate increases as you start to exercise. This increases the volume of blood reaching the muscles each second. More glucose molecules and oxygen molecules enter your muscle cells than when you are not exercising so they are able to release energy (through aerobic respiration) at a faster rate. Soon after you have begun to exercise, you will then find that you are breathing faster and more deeply. This is because the oxygen reserves in your blood are being used up faster than when you are at rest. By taking in more air to your lungs more often, your body can deliver more oxygen to the hard working cells. It also means that your body is able to rid itself of the waste carbon dioxide at a faster rate too.

If you exercise very hard for longer periods of time, your body cannot supply sufficient oxygen to the muscle cells. The cells will then try to make up for this shortfall of oxygen by using anaerobic respiration. But this is a poor way of releasing energy and so your muscles start to feel fatigued. During anaerobic respiration, lactic acid is formed which can lead to cramp.

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