Unlike with other medical conditions, which typically have outward signs, you could have high blood pressure and not even know it. High blood pressure, also known as hypertension, has been called the silent killer because blood pressure can be abnormally elevated without any signs or symptoms.
Hypertension is the most prevalent cardiovascular disease. The American Heart Association estimates that approximately 73 million Americans age 20 and older (about one in three) and 1 billion people worldwide have hypertension.6 Furthermore, the estimated direct and indirect costs of hypertension for 2010 equal $76.6 billion.6 These numbers are quite shocking!
Taking action to prevent or treat hypertension is vital. Those with untreated hypertension have a much greater occurrence of heart attack, abnormal thickening of the heart muscle, stroke, kidney problems, and heart failure. Although outward signs aren’t easy to identify, high blood pressure has a negative effect inside your body.
Blood pressure is reported as two distinct numbers: systolic blood pressure (top number) and diastolic blood pressure (bottom number). Both of these numbers are important, and they are expressed in millimeters of mercury (abbreviated as mmHg). At rest, the heart typically contracts between 60 and 80 times per minute. Every time the heart contracts, a pressure is generated that pushes against the major blood vessels. The pressure in the blood vessels during the heart’s contraction phase is called systolic blood pressure, and the pressure during the relaxation phase is called diastolic blood pressure.
Hypertension is defined as abnormally high resting blood pressure. As noted in table 15.1, a normal resting systolic blood pressure is less than 120 mmHg, and a normal resting diastolic blood pressure is less than 80 mmHg. So, what exactly qualifies as hypertension? Any one of the following is considered abnormal and thus considered hypertensive:4
Resting systolic blood pressure greater than or equal to 140 mmHg orResting diastolic blood pressure greater than or equal to 90 mmHg
The overriding goal of this chapter is to provide information on exercise and nutrition related specifically to hypertension. As you will soon learn, regular exercise and healthy eating have clear benefits for anyone with hypertension. Lifestyle modifications, which include regular exercise and proper nutrition, are currently advocated for the prevention, treatment, and control of hypertension.
A fundamental question is: What causes blood pressure to be too high? Nine times out of 10 the cause of the elevation in blood pressure is not known. In less than 1 out of 10 cases of hypertension the cause of the elevation in blood pressure can be attributed to a known problem such as kidney disease. In these cases the hypertension is considered secondary to the known disease; the other 9 out of 10 cases are referred to as essential hypertension (meaning there is no known cause). Because of very complex interactions, the precise mechanisms underlying essential hypertension are not likely to be understood anytime soon.
Although the cause of most cases of hypertension is not known, risk factors for hypertension have been identified and include the following:8
- Age. Your risk for hypertension increases with age. Over half of all Americans age 60 and older have hypertension.
- Race. Hypertension is more common among African American adults than among Caucasian or Hispanic Americans. Also, African Americans tend to become hypertensive earlier in life and have more severely elevated blood pressure.
- Family history. Hypertension often runs in families.
- Overweight or obesity. Prehypertension or hypertension is more likely for anyone who is overweight or obese.
- Lifestyle and nutritional factors. Various lifestyle and nutritional factors can raise your risk, including diets with too much sodium and not enough potassium, excessive alcohol consumption, smoking, and insufficient physical activity.
- Stress. Long-lasting stress can increase the risk of high blood pressure.
Consider the items on this list. Although some you cannot change (e.g., age, race, family history), there are a number that you can change or at least work to address. This chapter presents suggestions for increasing physical activity and improving nutrition to help lower your risk of developing hypertension.
The risk of cardiovascular disease and stroke increases as resting blood pressure increases (see figure 15.1). Although those with hypertension are at greater risk than those with prehypertension, it is important to note that those with prehypertension are at a greater risk than those with normal blood pressure. Although it is convenient to have firm boundaries separating hypertensive, prehypertensive, and normal resting blood pressures (as listed in table 15.1), resting blood pressure is directly related to cardiovascular risk and mortality (i.e., death rate) across a wide range of resting blood pressures, spanning all the categories. Risk begins to increase once resting systolic blood pressure exceeds 115 mmHg and diastolic blood pressure exceeds 75 mmHg.5
Read more about ACSM’s Complete Guide to Fitness & Health. Edited by Barbara A. Bushman, PhD, FASCM.