During vigorous exercise, your systolic blood pressure rises because your heart must work harder to pump more blood with each contraction to keep your muscles supplied with oxygen.
The more strenuous the exercise, the greater the rise in systolic pressure. During a very vigorous workout, systolic blood pressure in a healthy athlete may rise to as high as 200 mm Hg.
Normally, however, diastolic blood pressure changes very little, if at all. In a young, healthy person, diastolic blood pressure typically rises by no more than a few mm Hg
even during a strenuous workout. That’s because the blood vessels in your working muscles widen, decreasing peripheral resistance.