Unit 2 - Effects of Exercise

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.

Exercise your brain by playing this quiz on the effects of exercise on the body's systems and muscles!