Overview of the Disease

Blood pressure is defined as the amount of pressure exerted by blood on blood vessel walls as it passes through the vessel. Systolic blood pressure (SBP) is the highest pressure on the walls right after one single heartbeat. Diastolic blood pressure (DBP) is the lowest pressure on the walls right before a heartbeat. Hypertension, also known as high blood pressure, is defined as having a SBP ¡Ý 140 mm Hg and/or DBP ¡Ý 90 mm Hg. Hypertension is a primary risk factor for cardiovascular disease such as stroke, heart failure, angina, renal failure, and myocardial infarction or heart attack. It is also a stronger independent risk factor for mortality from coronary heart disease among elderly women than among elderly men.

Causes and Implications of Hypertension

Population factors associated with hypertension are obesity, high sodium intake, low potassium intake, physical inactivity, heavy alcohol consumption, and psychosocial stress. Accumulation of intra-abdominal visceral fat, which is fat located inside the body around organs instead of those right beneath the skin, and hyperinsulinemia also play a role in the development of the disease.

Hypertension causes the heart to do extra work in order to pump blood throughout a person\’s body. It promotes the presence of coronary calcium, which is a potential predictor of sudden death. It is associated with some changes in the brain, for example impaired cognitive function. It may lead to retinopathy, a degenerative disease in the eye, and nephropathy, a disease of the kidney. Finally, it induces thickening and stiffening of the medium and small blood vessels.

How May Exercise Reduce Hypertension?

The typical blood pressure response to acute bouts of aerobic exercise is a gradual increase in SBP and gradual decrease or no change in DBP. Age, gender, and body weight often cause variation.

First of all, exercise training can lower both cardiac output and peripheral vascular resistance at rest and at any given level of work. Lowered cardiac output is primarily due to reduced heart rate. All these help to reduce the amount of work needed from the heart in pumping blood. Next, exercise can decrease visceral fat and central fat deposition, rather than simply body weight, which will help reduce blood pressure in most people, especially in obese people. Specifically, aerobic exercise will decrease both resting SBP and DBP. Even exercises of moderate intensity can induce these beneficial changes. Finally, exercise training may reduce or eliminate the need for antihypertensive medications in patients with mild or severe hypertension.

Exercise Guidelines

The recommendations for exercise for those with mild hypertension are generally the same as those for healthy adults. Endurance, or aerobic, exercises are preferred, with a frequency of 3-5 days/week, duration of 20-60 minutes, and intensity of 60-85% of maximum heart rate. However for those with severe hypertension of markedly elevated blood pressure, the intensity should be lowered to about 50-70% of maximum heart rate.

In regards to weight training, this form of exercise usually results in increased SBP and an associated increase in DBP during the exercise bout. However, there is a smaller increase in heart rate compared to aerobic exercise. The blood pressure response between individuals contains great amounts of variability. Therefore a person should just exercise cautiously when performing any types of weight lifting. Interestingly, circuit training has been shown to result in a modest drop in DBP and no change in SBP.

Finally, for any person with hypertension, lifestyle modification including diet, weight loss, and exercise is much needed to help manage the disease.

Shaun Karp is a certified personal trainer in Vancouver. For further information call his office at 604-420-7800.