Why do veins pop out when exercising, and is that good or bad?
Mark A. W. Andrews, professor of physiology at the Lake Erie College of Osteopathic Medicine, offers this answer. Contrary to expectations, perhaps, bulging veins during exercise have nothing to do with an increase in either blood volume or pressure in these vessels. In fact, both are known to decrease during stepped-up activity, including exercise. To explain the prominence of veins during exercise, it helps to understand the vascular system and its components. Blood that circulates throughout the body is pumped from the left ventricle of the heart. It first enters into the high pressure arteries, where systolic blood pressure, the highest pressure exerted there, is recorded around 120 mmHg (millimeters of mercury), and diastolic pressure, the minimal pressure exerted in these vessels, is recorded at around 80 mmHg. (Thus, normal blood pressure is typically around 120/80 mmHg.) The blood flows into smaller and smaller branches of arteries called arterioles. As it continues along, its
