During physical exercise, the body requires more supply of

During physical exercise, the body requires more supply of oxygen. This is because during exercise, the body requires more energy to meet the demands of the muscles. Oxygen is required in the process of cellular respiration, which is the process that converts glucose and oxygen into energy in the form of ATP. When the muscles are working harder during exercise, they require more energy, and therefore require more oxygen to be delivered to them through the bloodstream. This is why breathing rate and heart rate increase during exercise, to help deliver more oxygen to the working muscles.