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. One study on older obese men showed blood pressures to be significantly lowered for 24 hours after aerobic exercise. Any decrease in blood pressure during exercise is a sign of potential heart problems and should be diagnosed by a physician. Any dramatic fall in blood pressure after exercise, without a return to close to normal levels within half an hour or so, also may signal potential heart problems. A person with blood pressure consistently below 90/60 should be referred to a physician.
Being inactive is linked to high blood pressure; therefore increasing your activity levels will reduce your blood pressure. If you have high blood pressure, your doctor or nurse may suggest that you try to become more active to lower it. However, you may be worried that regular exercise will increase your blood pressure to dangerous levels.
It is true that physical activity (exercise) will cause your blood pressure to rise for a short time. However, when you stop the activity, your blood pressure should soon return to normal. The quicker it does this, the fitter you are likely to be. Most people with high blood pressure should be able to increase their physical activity levels quite safely. However, if your blood pressure is relatively high, your doctor or nurse may prefer to lower it with medicines before starting you on an exercise programme. If your blood pressure is very high, you should not start any new activity without consulting your doctor. The table below gives a general idea of what levels you need to be concerned about, but bear in mind that every person is different, and your doctor or nurse may decide differently. To be safe, it is always a good idea to get advice from your doctor or nurse before you start any new physical activity.