Hypertension, also known as high blood pressure, is a medical condition in which blood pressure is chronically elevated. Blood pressure is defined as the force exerted by the blood against the walls of blood vessels. During a heartbeat, the heart muscle contracts, expelling blood into the arteries. The pressure against the arteries’ walls at this point is known as systolic pressure. When the heart is relaxed, the blood pressure is usually lower and is known as diastolic pressure. For adults, blood pressure is considered normal when systolic pressure is lower than 120 mmHg and diastolic pressure is lower than 80 mmHg.
When blood pressure is constantly elevated, the heart is forced to work harder than normal because it has to expel blood against greater resistance. This places blood vessels under great strain that can cause damage to their inner walls. Furthermore, this stress may eventually lead to atherosclerosis, heart attacks, heart failure or strokes. The problem is that hypertension usually doesn’t present any obvious symptoms and therefore may be easily overlooked if blood pressure is not measured periodically.
It is estimated that one in five American adults has hypertension. Epidemiologic studies have shown that African-Americans are more likely to develop high blood pressure than white non-Hispanic people. Older adults are also at greater risk. The pathophysiology of hypertension is not well understood, and in most cases, its origin is unknown. However, it is believed that several factors – heredity, race, age, sodium sensitivity, physical inactivity, and stress, among others – may increase the risk for hypertension.
High blood pressure is usually treated with a combination of medications and lifestyle changes. However, behavior modifications towards diet and physical activity may improve blood pressure to the point that medication is not needed.
Obesity is considered the number one lifestyle factor related to hypertension because excess weight makes the heart work harder to supply blood to the fat tissue. Thus, maintaining a healthy weight is an important preventive measure. Still, even modest weight-loss has also been shown to reduce blood pressure.
Sedentary lifestyles come in second place as a risk factor, meaning that regular exercise is a fundamental step to keep high blood pressure at bay. Aim for at least 30 minutes of moderate-intensity aerobic activities (such as walking, swimming, or cycling) on most days of the week.
Third, excessive alcohol consumption is responsible for around 10% of hypertension cases. If your drinking habits are currently out of control, limiting alcohol intake or avoiding it altogether may reverse the condition. The Dietary Guidelines for Americans recommends limiting alcohol intake to no more than one drink per day for women and no more than two drinks per day for men.
Fourth, excessive salt intake is linked to hypertension because too much salt leads to fluid retention, which increases blood pressure. However, recent research points out that sodium may not be the only culprit. It seems that other minerals (potassium, calcium, and magnesium) are also important to maintain a healthy blood pressure. Studies show that people who eat diets rich in potassium and calcium are less likely to develop hypertension. A study called Dietary Approaches to Stop Hypertension (DASH) has shown positive effects in reducing blood pressure. This diet emphasizes the consumption of fruits, vegetables, whole grains, and low-fat dairy while limiting the consumption of total fat, saturated fat and cholesterol. Furthermore, the combination of the DASH diet with sodium reduction (no more than 2,300 mg/day) may lower blood pressure even more.
Finally, do not smoke. Smoking raises blood pressure and is also a risk factor for other cardiovascular diseases.
References
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Thompson, W., et al, eds. ACSM’s Guidelines for Testing and Prescription. Baltimore, MD: Woters Kluwer and Lippinicott Williams & Wilkins. 2010.
United States. U.S. Department of Agriculture and U.S. Department of Health and Human Services. Dietary Guidelines for Americans, 2010. Washington, DC: U.S. Government Printing Office. 2010.
Wardlaw, G. and Smith, A. Contemporary Nutrition. New York: McGraw-Hill. 2009.
Wilmore, J., Costill, D. and Kenney, W. L. Physiology of Sport and Exercise. Champaign, IL: Human Kinetics. 2008.