Exercise is beneficial for the heart, improving its capacity to distribute blood efficiently to the body. The important measurements for the heart are pulse beats or heart rate and blood pressure. The heart rate is the number of times the heart beats per minute. Blood pressure is the force with which the blood is pumped, measured in two ways: Systolic refers to the pressure exerted when the heart pumps, and diastolic refers to the pressure between beats.
The recommended optimal normal blood pressure for healthy adults is 120 systolic and 80 diastolic. Blood pressure tends to rise in the evening and fall slightly after vigorous exercise; these readings typically are 130/85 and 110/70. Athletes training regularly usually are in the 110/70 range. Any reading over 140/90 is considered high and a reading under 90/60 low; either extreme may require medical treatment. Blood pressure normally is taken at rest, with the person seated and not doing any physical activity. This is the basis for comparison after exercise.
Blood pressure changes vary with the type of exercise. Aerobic exercise, such as running, swimming or bicycling, increases the heart rate and generally increases the pressure with which blood is pumped, thus raising the systolic number. The diastolic pressure normally remains stable. This is the preferred exercise for the heart. Static or isometric exercise, such as weightlifting, requires sustained muscle contraction with little or no increase in cardiac output; the result is a rise in both blood pressures. Isometrics have shown some beneficial long-term lowering of pressures, however.
It is normal for blood pressure to fall slightly below resting levels after vigorous exercise, then return to normal after rest. Heart rates should return to normal in about two minutes, but blood pressure returns are slower, often by several hours. Consistent aerobic exercise, however, has been shown to reduce resting blood pressure readings over time. The American Heart Association recommends at least 30 minutes of exercise three or four times a week to help control blood pressure. A cool down period after exercise allows heart rate and breathing to resume normal levels gradually and can help to prevent dizziness.