Exercise also causes vasodilation, or the widening of blood vessels, which increases blood flow and decreases peripheral resistance — which, in healthy people, keeps the diastolic blood pressure from rising during activity. In fact, a diastolic blood pressure increasing greater than 10 mmHg during or after exercise represents an unstable form of hypertension, and may be associated with coronary artery disease, notes Len Kravitz, Ph.D. of the University of New Mexico.

Unlike high blood pressure symptoms, which are poorly defined and often totally absent, low blood pressure symptoms tend to be more upfront and easily recognizable. The development of symptoms is often a warning sign of a potentially serious underlying disorder. Generally speaking, your blood pressure would need to fall pretty dramatically before symptoms develop.
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