By Jennifer Green, B.S.

Jennifer Green, NCHPAD Visiting Information Specialist

High blood pressure (BP), also known as hypertension, is the most common cardiovascular disease and is defined as chronically elevated blood pressure greater than 140/90 mmHg. Roughly 74.5 million people in the United States age 20 and older suffer from hypertension, or roughly 1 in 3 adults. Elevated blood pressure is often referred to as the 'silent killer' because it is not recognized by a given set of symptoms or feelings. This disease is a serious medical problem when left untreated and significantly increases one's risk of developing coronary artery disease and stroke.

Recently published studies suggest that moderate-intensity physical activity may be effective in lowering blood pressure. Proposed mechanisms for the blood pressure-lowering effects of exercise include neurohumoral, vascular, and structural adaptations. Regular physical activity has been shown to reduce the risk of developing hypertension by 19% to 30%. Research has also found that having low cardiorespiratory fitness at middle age is associated with a 50% greater risk of developing hypertension.

In a recent statement on exercise and hypertension, the American College of Sports Medicine (ACSM) concluded that people with mild hypertension can expect both systolic and diastolic blood pressure to fall an average of 10 mmHg in response to regular aerobic exercise. The benefits of regular physical activity are seen quickly, with most changes taking effect within the first few weeks. With such a large portion of our population currently suffering from hypertension and another significant portion at risk for the disease, it is important that trainers and exercise professionals understand how to safely and effectively create an exercise prescription for these individuals.

ACSM suggests exercising 3 to 5 days per week for 20 to 60 minutes at a moderate intensity (50%-90% HRmax) in order to effectively lower blood pressure. The core of an exercise prescription in this population should consist of aerobic activity, including but not limited to walking, jogging, cycling, and swimming.

The evidence is conflicted in regards to strength training in this population. Some published data has suggested that weight training should be avoided in individuals with hypertension, since it causes such a spike in blood pressure. More recent studies have shown that there may be some additional benefit in hypertensive patients. Strength training is an important factor in increasing muscular strength and overall physical fitness. Therefore, once aerobic conditioning improves, add low-resistance, high-repetition weight training into the client's exercise prescription. During strength training, holding one's breath should be avoided since it can result in large fluctuations in blood pressure.

As in any population, there are some special considerations that trainers and exercise professionals must keep in mind when working with this population. According to ACSM, these considerations include:

• People using medications, such as beta-blockers, should be cautious of developing heat illness when exercising. These medications and diuretics impair the ability to regulate body temperature.
• Adults with hypertension should extend the cool-down period of the workout. Antihypertensives, such as alpha blockers, calcium channel blockers, and vasodilators, may cause BP to lower too much after abruptly ending exercise.
• Overweight and obese adults with hypertension should combine regular exercise and weight loss to effectively lower resting BP.
• Promoting the BP-lowering effects of single exercise sessions may best motivate people to exercise. Physicians are encouraged to promote the role of exercise in controlling BP to their patients.
• A physician evaluation and clearance is necessary for those with severe or uncontrolled BP prior to beginning an exercise program. Higher-risk patients (such as those with coronary artery disease or chronic heart failure) should lessen the intensity of their training program.

Physical activity has been shown to have a therapeutic role in the treatment of hypertension. As always, individuals who are currently hypertensive should receive medical clearance from their primary care physicians before starting an exercise program, and exercise prescriptions should be based on medical history and risk factor status as well as any antihypertensive medications your client may be taking. With the proper knowledge and program design skills, exercise professionals can play a crucial role in the fight against this silent killer.

Resources:

High blood pressure statistics. (2010). Retrieved March 31, 2010, from http://www.americanheart.org/presenter.jhtml?identifier=4621.

Nieman, D. C. (1996). Exercise: The right prescription for hypertension, regular aerobic exercise is key to lowering your blood pressure-hypertension. Retrieved March 31, 2010, from http://findarticles.com/p/articles/mi_m0826/is_n1_v12/ai_18001426/.

Pescatello, L. S, Ph.D, FACSM, Franklin, B. A. Ph.D, FACSM, Fargard, R., MD, Ph.D, FACSM, Farquhar, W. B. P., Kelley, G. A. D.A., FACSM, & Ray, C. A. Ph.D, FACSM. (2004). American College of Sports Medicine position stand: Exercise and hypertension.

Roy, B. A. P. (2010). Exercise and hypertension. Retrieved March 31, 2010, from http://www.acefitness.org/fitfacts/fitfacts_display.aspx?itemid=110.

---

Please send any questions or comments to Jennifer Green at green1jn@uic.edu.