EVERYDAY SCIENCE

Detailed explanation-1: -During heavy exercise, fast running, cycling, walking for many hours or heavy weight lifting, the demand for energy is high but the supply of oxygen to produce the energy is limited. So, the heart rate increases to supply more oxygen and glucose to the respiring cells.

Detailed explanation-2: -The more the heart beats, the more breathing occurs. As the heart beats faster, it uses more energy and sends more oxygen to the body. If a person is exercising the oxygen is used very quickly in order to provide the muscles with needed energy to move. Thus the heart beats faster to pump more oxygen to the muscles.

Detailed explanation-3: -Answer and Explanation: Exercise increases the rate of cellular respiration. This occurs because of the need for greater amounts of ATP in the muscle tissue.

Detailed explanation-4: -Additionally, the study found evidence that exercise may encourage cells to make more RNA copies of genes coding for mitochondrial proteins and may increase the ribosome’s ability to make mitochondrial proteins. When a muscle contracts, the muscle cells produce and release molecules called myokines.

Detailed explanation-5: -During exercise, your heart typically beats faster so that more blood gets out to your body. Your heart can also increase its stroke volume by pumping more forcefully or increasing the amount of blood that fills the left ventricle before it pumps.