Question

If we run we need enough oxygen so we breathe faster. Why our heart beats fast?

Answer 1

Our heart beats faster when we run as the muscles require more oxygen and fuel. Increased heart rate can increase the flow of blood and nutrients and oxygen to and removing waste away from working muscles. Also if we are competing in a race we may release adrenaline (Americans called it ephedrine) which is a flight or fight hormone, this will increase heart rate and may help us run faster too