Hypertension (high blood pressure) affects approximately 58 million individuals 18 yrs or older in the US and approximately 1 billion people worldwide. Or, stated another way, hypertension affects about 29% of Americans and 1 out of every 6 persons on earth!

But wait, it gets even worse:

The Framingham Heart Study analyzed the risk of developing hypertension in roughly 1300 subjects ages 55-65 years old who did not currently have high blood pressure. In this study, more than half of the 55-year-olds and about two-thirds of the 65-year-olds developed hypertension within the ensuing 10 years (Vasan RS, et al. 2002). The authors concluded that "the residual lifetime risk for hypertension for middle-aged and elderly individuals is 90%....". Yes, that's right: NINETY PERCENT!

This is absolutely staggering. What this says is that, once you reach retirement age, you almost certainly will develop hypertension later in your life. And hypertension, in turn, increases the risk for other major medical conditions such as kidney failure, stroke, and heart disease.

HEALTH COUNSELING NEEDS TO IMPROVE

Why is this "epidemic" of hypertension happening? Should we blame ourselves, or, has our medical community let us down? Certainly, health care professionals are screening for it: the results of a survey in 2000 showed that hypertension was the most common primary diagnosis in the US with 35 million office visits (Cherry DK, et al. 2002).

But when it comes to health counseling, physicians aren't doing as much as they should. Despite the fact that the nurse takes your blood pressure at every single office visit, how often has your own personal physician actually discussed the benefits of exercise with you? Not just in general terms, but I mean sitting down and having an honest face-to-face discussion that goes something like: "Dan, you need to start exercising. What I want you to do is to start walking 30-45 minutes per day five days per week, and I want you to start today."

The sad fact is that most physicians don't have these discussions with their patients (Ma J, et al. 2004). Managed care limits the amount of time physicians spend with each patient and, often, it's just easier to write a prescription and toss the patient a handout on "Managing Hypertension" or "Managing Cholesterol" or the like.

To be painfully honest, we should really blame ourselves. We simply don't take care of our health like we should. We smoke, we don't exercise enough, and we eat salty, high-fat foods. Two-thirds of Americans are overweight. Eating a healthy diet, losing weight, and, especially, exercising regularly not only lowers blood pressure, but, quite possibly, could prevent hypertension from ever developing.

So, with that in mind, let’s review some of these issues.

"NORMAL" BLOOD PRESSURE

What is normal blood pressure? Actually, it’s better to ask, what is the "optimum" or "desired" BP? For some people, their "normal" blood pressure (ie., their typical day-to-day BP) may actually be too high.

For many years, desirable blood pressure was considered to be 120/80 and treatment was instituted when BP was 140/90 or higher. However, the relationship between BP and risk of cardiovascular disease is linear. In other words, as BP goes up, so does the risk of events like heart attack (myocardial infarction), heart failure, stroke and kidney disease. As BP increases from 115/75 to 185/115 mm Hg, each 20/10 BP (ie., systolic/diastolic) increment doubles the risk of these cardiovascular events (JAMA May 21, 2003).

On the other hand, elite athletes and aerobically-fit individuals may demonstrate a resting BP much lower than others. This is not harmful, nor unusual. In an aerobically-trained athlete, the heart is more efficient: it pumps more blood per stroke. The circulatory system overall improves as fitness improves: more oxygen is extracted from the blood with each heart beat. Oxygen uptake (see Articles for a separate discussion on this topic) is higher in an athlete than in a sedentary person. In an athlete, the heart is stronger, and the heart rate is slower. Both contribute to a lower resting blood pressure.

EFFECTS OF AEROBIC EXERCISE ON HYPERTENSION

Studies of the effects of exercise on hypertension have been conducted since the 1970s and several reviews of these studies have been published. But first, let's make a distinction between the immediate effects of exercise on blood pressure and the long-term effects of regular exercise on hypertension:

Blood pressure can fluctuate across a wide range depending on the activity at the time. During extreme effort, BP in some athletes can briefly rise to astronomical readings. For example, pressures as high as 480/350 have been documented in the brachial artery of a body-builder during a leg-press exercise (MacDougall, et al. 1985). For the rest of this discussion, we are going to disregard acute effects; we will only focus on the long-term effects of regular exercise.

Most of the research on the effects of exercise on hypertension has evaluated aerobic exercise. Examples of aerobic exercise include walking, running, biking, swimming, playing tennis, etc....anything that gets the arms and legs moving and gets the heart rate up for a sustained period of time.

In 2002, an extensive review of the medical literature showed that aerobic exercise lowered BP not only in hypertensive patients, but also in normotensive patients, overweight subjects, and normal weight subjects. The average drop in blood pressure was 3.9/2.6 mmHg. When only hypertensive patients were analyzed, the average drop was 4.9/3.7 (Whelton SP, et al. 2002). A Japanese study was even more impressive: aerobic exercise lowered BP by as much as 20/10 (systolic/diastolic) mmHg after 20 weeks (Kiyonaga A, et al. 1985).

But, exactly how much and what kind of exercise is necessary? Here are some specifics:

Running

Cycling

Swimming

HOW VIGOROUS SHOULD AEROBIC EXERCISE BE?

In one study, overweight, sedentary subjects underwent 45 minutes of aerobic exercise at 70-85% of their personal heart rate reserve. The aerobic activity was either biking, jogging, or walking, and this was performed 3-4 times per week for 6 months. At the end of the study, this aerobic exercise program lowered both systolic and diastolic BP by 6 mmHg (Georgiades A, et al. 2000).

This is an impressive response, but exercising at 70-85% of heart rate reserve is pretty tough for many people. How effective is less vigorous exercise?

It turns out that plain old walking can lower blood pressure. In one study of post-menopausal women, walking 3-km/day for 24 weeks lowered systolic BP by 6 mmHg (Moreau KL, et al. 2001). A review of 16 other studies showed that walking produced an average drop in blood pressure of 3/2 (systolic/diastolic) mmHg after 25 weeks (Kelley GA, et al. 2001).

SHOULD PEOPLE WITH HYPERTENSION AVOID RESISTANCE EXERCISE?

As mentioned above, blood pressures as high as 480/350 have been documented in an athlete during weight-lifting. So, does this mean that weight-lifting is bad for people with hypertension?

During aerobic exercise, heart rate increases dramatically, while blood pressure increases only slightly. The opposite is true for resistance exercise (ie., blood pressure increases to astronomical readings, but heart rate increases only slightly).

But, an increase in either measurement (ie., blood pressure, or, heart rate) increases demand on the heart.

To compare the impact of each form of exercise on the heart, something called the "rate-pressure product" [ie., (heart rate) x (blood pressure)] is calculated. This value can often be higher for aerobic exercise than for resistance exercise. This means that the demands on the heart can be greater for aerobic exercise than for resistance exercise (Stewart KJ. 2000). So, resistance exercise should not be avoided. The American Heart Association recommends resistance exercise in the range of 30-60% of maximum effort in patients with hypertension.

IS RESISTANCE EXERCISE EFFECTIVE FOR LOWERING BP IN PEOPLE WITH HYPERTENSION?

Resistance exercise is mostly thought of as weight-lifting, but push-ups, sit-ups, pull-ups, squats, etc. also qualify as resistance exercise.

At least 11 studies have evaluated the effectiveness of resistance exercise on hypertension (Pescatello LS, et al. 2004). These studies are not consistent in their findings. In 2000, a review of this literature showed that resistance exercise was effective: at rest, both systolic and diastolic BP decreased by an average of 3 mmHg (Kelley GA, et al. 2000).

OFFICIAL EXERCISE RECOMMENDATIONS

An extensive review of the literature (54 studies) published in 2002, suggested that all forms of exercise can be beneficial in hypertension (Whelton SP, et al. 2002). Aerobic exercise should be emphasized, with some resistance exercise included. A combination of aerobic exercise (eg., 45 minutes of treadmill, stationary cycling, or stair-stepper exercise) with 7 different weight-lifting exercises 3 days per week was evaluated in elderly subjects (ages 55-75 yrs). This regimen produced a modest (2.2 mmHg) drop in diastolic BP after 6 months (Stewart KJ, et al. 2005). This drop in BP may not seem like much. However, combining resistance exercise with aerobic exercise will provide health benefits beyond simply lowering blood pressure. For example, weight-lifting will increase bone density and may help with posture and activities of daily living.

During the past 10 years or so, the idea of "prescribing" exercise as a treatment for some health conditions has gained attention. However, until very recently, there really wasn't a consensus on what worked best for hypertension. In 2002, the National High Blood Pressure Education Program (Whelton PK, et al. 2002) recommended:

"regular aerobic physical activity such as brisk walking at least 30 min/day on most days of the week".

In March 2004, the American College of Sports Medicine, one of the leading research organizations regarding the physiologic effects of exercise, published their latest recommendations regarding exercise and hypertension (Pescatello LS, et al. 2004). Here they are:

The "prescription" for exercise consists of 4 elements, represented by the acronym "FITT": frequency, intensity, time, and type.

• Frequency: exercise should occur on most, preferably all, days of the week.
• Intensity: exercise intensity should be moderate (ie., 40-60% of VO2max).
• Time: duration of exercise should be at least 30 minutes per day; this can be achieved in one continuous session, or, a sum total of smaller periods of exercise throughout the day.
• Type: endurance (aerobic) exercise is preferred, but resistance exercise should not be ignored.

If we reduced all this technical language down to more simple terms, it might be something like this:

walk briskly for 30-45 minutes per day, 5-7 days per week.

NOTE: If your blood pressure is high, you should NOT engage in strenuous exercise without first being evaluated by your physician. Further, if you have already seen your physician and you are currently taking medication to lower your blood pressure, generally, you still should not engage in strenuous exercise until the drug therapy has brought your blood pressure into a more normal range. This is very important, especially if you are older, or, if your blood pressure is very high.

CAN REGULAR EXERCISE PREVENT HYPERTENSION?

At the beginning of this discussion, I mentioned the extremely discouraging statistic that suggests the risk of developing hypertension as you get older is 90%. The immediate next question is: is there any evidence that regular exercise will, in fact, prevent hypertension? And the answer is yes!

Paffenbarger et al. studied Harvard alumni and found that those who did not engage in vigorous activity were at a 35% greater risk of hypertension than those who did. In this study, they defined "vigorous" activity as running, swimming, handball, tennis, cross-country skiing, etc. (Paffenbarger R, et al. 1983).

This 1983 Harvard alumni study found that vigorous exercise, but not light exercise, helped to reduce the risk of developing hypertension in later life. However, another study, in Japanese men, showed that walking for only 20 min/day successfully lowered the long-term risk of developing hypertension (Hayashi T, et al. 1999).

QUESTIONS

Q: Can I exercise while taking medication for hypertension?

ANSWER: First, if you are taking medications for hypertension, do NOT begin a new exercise program without discussing your plans with your physician.

Having said that, many physicians are not well-versed on the issues that may arise regarding exercising while taking blood pressure medication. One reason is that issues that may arise when exercising while taking drug therapy are not widely known.

The topic of exercising while taking drug therapy for hypertension is too complex to review here. Keep in mind that there are over 200 unique prescription drugs for the treatment of hypertension on the US market. Even reviewing them categorically (eg., diuretics, beta-blockers, ACE inhibitors, calcium-channel blockers, etc.) would be a lengthy discussion. One issue worth noting, however is that beta-blockers are often not a good choice for exercisers due to their ability to interfere with energy utilization and limit exercise heart rate (Reents S, 2000). Some clinicians feel that beta-blockers should be the last choice for patients who wish to exercise (Houston MC. 1992).

Some studies have shown that regular exercise can reduce or even eliminate the need for antihypertensive medications (Ketelhut RG, et al. 2004). For example, in hemodialysis patients, a 6-month cycling program led to a 36% decrease in the use of antihypertensive medications (Miller BW, et al. 2002).

Q: Dietary changes vs. exercise: which is more effective for lowering blood pressure in hypertension?

ANSWER: Diet and exercise are often lumped together by the medical community. But, which is more effective for hypertension? First, let's make a distinction between "diet modification" and "dieting". "Diet modification" is represented by changes to the diet (such as restricting sodium) without trying to lose weight. "Dieting", of course, means reducing calorie intake in order to achieve weight loss.

• Dietary Modification: For years, physicians have instructed their patients with hypertension to limit their intake of salt/salty foods. The latest recommendations in the Dietary Guidelines for Americans, 2005 state: "not more than 2300 mg/day in healthy adults; not more than 1500 mg/day in patients with hypertension".

It turns out that this strategy doesn't lower BP very much. In one study, the drop in BP (systolic/diastolic) was only 1.7/0.9 (JAMA 1992), and in a review of 13 other studies, the average drop was only 3.6/2.0 (Grobbee DE, et al. 1986). However, even small drops in systolic BP are still significant because the risk of stroke and heart disease are reduced when large populations are studied. Also, black patients with hypertension should limit their intake of sodium as they seem to be more sensitive to its effects.

So, the answer is, yes, it is wise to reduce salt intake when managing hypertension. Restricting sodium is almost always a good health choice. One exception is the case of endurance exercise. For example, if you decide you want to walk or jog a marathon as your form of exercise, or, go on a 100-mile bike ride, or, do anything that causes you to perspire heavily over several hours, then, you need to make sure you take-in enough sodium. This is an entirely different topic and is discussed in "Why Sports Nutrition Is Different".

• Dieting (ie., weight loss): Simply losing weight helps to lower BP in many patients with hypertension. Weight loss has been shown to be more effective in lowering blood pressure than a variety of dietary modifications (JAMA 1992). In fact, some researchers believe that controlling obesity might alleviate as much as 48% of the hypertension in whites and 28% of the hypertension in blacks (El-Atat F, et al. 2003).

So, when comparing diet vs. exercise for the management of hypertension, the best approach is a combination of: (a) proper diet (salt and calorie restriction), (b) weight loss, and (c) regular exercise. Dieting is beneficial if weight is lost, since, treating obesity helps to lower blood pressure. However, dieting does not strengthen the heart, lungs, muscles, and bones; only exercise can do this.

SUMMARY

To have a beneficial effect on lowering your blood pressure, you don't have to endure punishing amounts of exercise. It turns out that plain old walking is good enough to attain a blood-pressure-lowering effect. Even cutting the grass, if you use a push mower, qualifies.

Keep these points in mind:

• First, if you have high blood pressure, or any form of cardiovascular disease, do NOT engage in strenuous exercise without being evaluated by your physician.

• If you are overweight or obese, lose that weight.

• Emphasize aerobic exercise, though, once your blood pressure is under control, don't ignore resistance exercise.

Hypertension is a disease that generally persists for life. But, evidence shows that regular exercise, combined with weight loss (if you are overweight), and limiting your intake of salty foods can help to lower an elevated blood pressure. Further, exercise improves other cardiovascular problems, too (Stewart KJ. 2002). More importantly, these lifestyle elements may actually prevent hypertension from ever developing in the first place. So, get out there!

FOR MORE INFORMATION

American Heart Association www.AmericanHeart.org: This site contains good information on hypertension and other cardiovascular diseases.

Centers for Disease Control and Prevention (CDC) www.cdc.gov: There is a ton of useful public health information on this site.

National Heart, Lung, and Blood Institute www.nhlbi.nih.gov: The National Heart, Lung, and Blood Institute is a division of Health and Human Services. This site contains a lot of useful information on hypertension. The NHLBI also coordinates the National High Blood Pressure Education Program, which originated in 1972.

International Council on Active Aging (ICAA) www.icaa.cc: ICAA focuses on wellness during aging.

National Institute on Aging www.niapublications.org: offers free publications for consumers, including an exercise guide.

Small Steps Program www.smallstep.gov: This is a web site maintained by the US Department of Health and Human Services. Some good information is located here.

Readers may also be interested in these reviews:

• Exercise and Obesity
• Fluids and Electrolytes During Exercise
• Running: An Overview
• Why Sports Nutrition Is Different

PERSONALIZED FITNESS and WELLNESS COUNSELING

If you'd like some help designing your personal fitness program, or have questions regarding exercise, or simply want some regular motivation, sign-up for our Fitness Counseling Service.  It may be the best investment in your health that you'll ever make.

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ABOUT THE AUTHOR

Stan Reents, PharmD, is a former healthcare professional. He holds Personal Trainer and Lifestyle Counselor certifications from the American Council on Exercise and has been certified as a tennis coach by USTA. He is the author of Sport and Exercise Pharmacology (published by Human Kinetics).  He can be reached at: Editor@athleteinme.com.