Blood Pressure and Exercise

Question:
Has anyone ever heard of a mechanism that would lower blood pressure immediately after vigorous exercise? Could plaque in blood vessels be removed during vigorous exercise, causing a lower blood pressure at the end? Or might exhaustion be responsible for a relaxation not normally achieved? Simply put, what factors play a role determining blood pressure and are there ways to lower it?
Answer:
(You better hope that an exercise session does not remove plaque in blood vessels. Recent research shows that plaques traveling through the blood vessels may cause heart attacks.)
Blood pressure readings as high as 240/120 during aerobic exercise and 350/150 during strenuous weight training are not unusual. Also, systolic pressure (the top number) should rise linearly as exercise intensity increases. So you should expect blood pressure to drop after exercise.
However, an unexpected or unreasonable drop in BP may indicate a major medical condition. If that's the case, you should ask your client to see a physician.
Blood pressure is the product of cardiac output and peripheral vascular resistance. From a physiological point of view, age, weight, gender, ethnicity and family history all affect blood pressure.
Mechanically speaking, the pumping of the heart creates a force as the blood pushes against the walls of the arteries and arterioles. (Pressure is force divided by a unit of area.)
The arteries and arterioles create resistance to the blood flow from the heart. As arterioles contract, resistance to blood flow increases, thus blood pressure increases. The opposite happens as arterioles expand.
Immediately after exercising, a drop in blood pressure is natural and expected. Muscle contractions help pump blood back to the heart. Once you stop exercising and these contractions dissipate, the heart responds by decreasing cardiac output, and blood pressure drops.
An acute bout of exercise also dilates the blood vessels. This means less resistance to blood flow and a decrease in blood pressure.
Studies have shown that moderate aerobic exercise (like walking) may be more effective in lowering resting blood pressure than more intense exercise. Specifically, a recent National Institutes of Health (NIH) study showed that aerobic exercise can reduce systolic blood pressure by 11 mmHg and diastolic BP by 9 mmHg.
According to research in Exercise Physiology, the precise mechanism for the exercise-lowering effect of blood pressure is not known, although it may occur because of a reduction of the catecholamines with training.