How does blood pressure change during heavy exercise?

The blood pressure is increased to pump more blood to distribute more oxygen to the muscles

Explanation:

When we do activities that demand heavy exercise like running, our body needs more oxygen to carry out property the exercise. Oxygen is transported to muscles by the circulatory system (principally blood), our heart starts to pump faster the blood (increase the blood pressure) to distribute the oxygen between muscles, consequently, we start to breathe faster to increase the oxygen intake.