What are the advantages to the body in the change in breathing and heart rates?

Your pulse rate increases from 75 per minute to 180 per minute during severe exercise. Your cardiac out put increases from five liters to twenty five liters per minute. Your muscles get about 20 liters of blood, during exercise. Resting blood flow to muscles is about 750 ml per minute. This much blood supply can be managed by increased pulse rate only. Increased breathing rate supply that extra oxygen needed to muscle tissue.