Lifestyle Modifications for Prevention and Treatment of Hypertension

Modifications of lifestyle are often critically important to adequately control existing hypertension. The elevated blood pressure (BP) of patients who are gaining weight, performing little physical activity, smoking and drinking alcohol in excess may be impossible to control despite progressively increasing doses of multiple medications.

Modification of lifestyle are even more important to a much larger population of patients, those who are genetically predisposed to develop hypertension if exposed to adverse environmental factors. As a consequence of the rapid growth of these environmental factors—including obesity, physical inactivity, stress, excessive alcohol consumption, and too much dietary sodium plus too little dietary potassium—the incidence of hypertension continues to increase. Obviously, everyone would benefit from the prevention of hypertension, a far more effective way to reduce the personal and societal burdens of cardiovascular disease (CVD) than the treatment of the established disease.

PREVENTION

The ability to prevent hypertension has never been well documented and may never be conclusively demonstrated. What has been documented is the ability to decrease the usually progressive rise from high‐normal BPs, i.e., diastolic levels from 80–89 mm Hg, to overt hypertension, i.e., diastolic levels >90 mm Hg, in relatively small groups of subjects by the use of various lifestyle modifications. To achieve meaningful prevention, both a population‐based approach and an intensive targeted strategy focused on those who were at high risk for hypertension, either from heredity or from adverse environmental factors, are needed.

Researchers concluded that six approaches have been shown to be effective in the prevention of hypertension. These are: 1) performance of moderate physical activity; 2) maintenance of normal body weight; 3) limitation of alcohol consumption; 4) reduction of dietary sodium intake; 5) maintenance of adequate dietary potassium intake; and 6) consumption of a diet rich in fruits, vegetables, and low‐fat dairy products and reduced in saturated and total fat.

TREATMENT

Lifestyle modifications are indicated for virtually all hypertensives. Adverse lifestyle habits that raise BP are virtually ubiquitous in those with hypertension and may play a major role in the development of the disease. In practice, multiple modifications of lifestyle can lower BP more effectively than single approaches. Their use was highly correlated with the control of hypertension among a large cross‐section of the US population in the third National Health and Nutrition Examination (NHANES III) population.

Observational and trial data support the importance of multiple simultaneous modifications of lifestyle to approach the greatest benefit on lowering BP and reducing overall cardiovascular risk status. The impressive effects of programs such as the Dietary Approaches to Stop Hypertension (DASH) diet could reflect the role of multiple factors. Although success in modifying lifestyle may be as difficult to achieve as keeping patients on long‐term antihypertensive drug therapy, even a small persistent reduction in BP can have a major protective effect on CVD.

Effects of Smoking on BP

Smokers and users of smokeless tobacco generally have been found to have higher daytime ambulatory BP than nonsmokers; however, if clinic BP is measured when smokers are not smoking, they may have lower BP than nonsmokers, likely because they weigh less.

Tolerance does not develop to the pressor effect of nicotine and sympathetic outflow increases with each cigarette. Insulin resistance is greater in smokers, as is visceral obesity. All of these and many other adverse effects of smoking contribute to an increase in CVDs, including stroke, and has a major impact upon progression of renal dysfunction.

Interventions to Stop Smoking

Repeated demands by physicians to their patients to stop smoking are helpful. Nicotine replacement therapies are effective and have minimal pressor effects, probably because they provide a lesser and slower rise in plasma nicotine.

Scope of the Problem

Obesity is growing at a rapid rate in all developed and developing societies. The consequences of even small amounts of increased weight are impressive. Women over 18 years of age with an initial body mass index of 24 developed diabetes five times more and hypertension twice more than in women with a body mass index <21.

Most of this increased weight is deposited in the upper body, comprising a major component of the metabolic syndrome (Table I) that is now present in almost half of men and women over 60 years of age in the United States. [Upper‐body obesity is a risk factor for hypertension independent of body mass index. In most societies, obesity is increasing most rapidly among children, largely as a consequence of physical inactivity. Therefore, it is critical to improve the increasingly "toxic" environment that is responsible for the epidemic of childhood obesity (Table II).

Table I.

The Metabolic Syndrome

Risk Factors	Defining Levels
Abdominal obesity (waist circumference)
Men	>102 cm (>40 in)
Women	>88 cm (>35 in)
Triglycerides	≥150 mm/dL
High‐density lipoprotein cholesterol
Men	<40 mg/dL
Women	<50 mg/dL
Blood Pressure	≥130/≥85 mm Hg
Fasting glucose	≥110 mg/dL

Table II.

Ways to Clear the Toxic Environment for Children

Home	Provide time for healthy meals and physical activity Limit television and computer games
School	Require physical activity Provide healthful foods and snacks
Urban design	Protect open spaces Build easy accesses for physical activity
Marketing	Tax fast food and soft drinks Subsidize nutritious foods Require nutrition labels on all packages Prohibit marketing directly to children

Obstructive sleep apnea, often present in obese hypertensives, is much more common than now recognized and can lead to sustained hypertension. Relief of sleep apnea can lower BP.

Benefits of Weight Reduction

In virtually every study of weight reduction, systemic BP is reduced, even if the degree of weight loss is small. In general, the greater the weight loss,the greater the reduction in BP. With the marked weight loss accomplished by gastric surgery, the prevalence of hypertension is markedly reduced.

PHYSICAL ACTIVITY

People who regularly perform physical activity have less CVD and the protection is as great with walking as with more vigorous exercise. The higher the level of exercise capacity, the lower the cardiovascular mortality with an association that is as strong as that seen with other cardiovascular risk factors. Regular aerobic physical activity has even been found to improve sexual function in obese men with erectile dysfunction.

The BP falls during aerobic exercise and remains lower for the remainder of the day. The overall antihypertensive effect is greater with a longer duration of exercise, but not with more intensive aerobic exercise. A similar reduction in BP has been seen with progressive resistance exercises.

DIETARY SODIUM REDUCTION

Although sodium sensitivity varies between individuals, a moderate reduction in dietary sodium intake will help prevent and treat hypertension. The average decrease in BP with acute increases in sodium excretion is greater in hypertensives than in normotensives and in the elderly than in the younger individuals. Such greater degrees of sodium sensitivity are associated with reduced long‐term survival.

A significant fall in BP has almost always been noted in trials of dietary sodium reduction. The addition of a lower sodium intake to the DASH diet provided an additional reduction in BP.

The degree of sodium reduction that was maintained in randomized controlled trials that go beyond 6 months' duration has been relatively small. In the 11 such trials that were reviewed, dietary sodium reduction averaged 33 mmoL/d with only a 1.1/0.6 mm Hg reduction in BP and no effect on mortality. It is likely that the minimal effects were directly related to the small degree of sodium reduction that was maintained.

More stringent reductions in sodium intake may, however, be counterproductive by activating the renin‐angiotensin and sympathetic nervous systems. In an 8‐week trial wherein sodium excretion was reduced from 220 mmoL/d to 80 mmoL/d, these activations were noted, yet the BP fell by an average of 7/5 mm Hg.

Beyond the effects on BP, higher levels of sodium intake have been associated with multiple other adverse effects. In a prospective follow‐up of 2400 Finnish men and women, a 100 mmoL/d higher sodium excretion was accompanied by a 45% increase in CVD and a 26% increase in all‐cause mortality. Greater left ventricular mass and increased urinary albumin excretion were noted with higher levels of urinary sodium excretion independently of the BP.

In view of the difficulty in maintaining dietary sodium intake by individuals in today' high‐salt environment, reduction in the amount of salt added to processed foods—the source of 75% of sodium intake—is the logical way to achieve the benefits of moderate dietary sodium reduction. This can be done with ease by reading the label that lists the amount of sodium. Avoiding processed foods with more than 400 mg sodium per portion is a helpful way for patients to achieve the goal.

INCREASES IN POTASSIUM INTAKE

In 33 randomized controlled trials of potassium supplementation, a significant antihypertensive effect has been seen, greater in blacks and in the presence of higher dietary sodium intake. Increased dietary consumption of potassium has been associated with a lower risk of stroke. The extra potassium in diets with more fresh fruits and vegetables may contribute to the reduction of BP as seen in the DASH and other controlled trials.

MODERATION OF ALCOHOL CONSUMPTION

Acutely, large quantities of alcohol lower both BP and arterial stiffness, but chronic excessive drinking of more than three portions per day raises BP. On a chronic basis, as seen in a 6‐year follow‐up of 8334 normotensives aged 45‐64 years at baseline, lower‐to‐moderate levels of alcohol consumption were associated with a higher incidence of hypertension in black men but not in the other groups, whereas more hypertension was seen in all groups consuming >210 g ethanol per week (equivalent to 18 portions). Similarly, over an 8‐year follow‐up of 70,891 women aged 25‐42 years of age, the risk of developing hypertension was reduced by 14% in those who drank one‐quarter to one‐half portion per day and was increased by 31% in those who drank more than two drinks per day. In those who drink more than six portions per day, a reduction down to less than two per day is accompanied by a fall in BP.

In multiple populations, moderate consumption of any type of alcohol‐containing beverage has been associated with lesser risks for heart attack, heart failure, ischemic stroke, diabetes, and dementia. The greater protection reported with wine, red wine in particular, compared with other types of alcohol may reflect healthier lifestyle habits in those who drink wine.

OTHER MINERALS

Calcium: A meta‐analysis of nine dietary and 33 nondietary supplementation trials showed an overall, statistically significant reduction of BP by 1.44/0.84 mm Hg. Magnesium: A meta‐analysis of 20 randomized controlled trials (RCTs) of magnesium supplementation, averaging 15.4 mmoL/d, found a statistically insignificant 0.6/0.8 mm Hg fall in BP, however, there was an apparent dose‐related effect.

OTHER DIETARY CONSTITUENTS

Caffeine: In 24 hypertensive subjects, consumption of 5 cups of coffee per day, containing 300 mg of caffeine, was associated with an average 4.8/3.0 mm Hg increase in 24‐hour ambulatory BP. Similar amounts of green or black tea produced immediate rises in BP but minimal effects after 60 min. Fiber: A meta‐analysis of 12 RCTs published before 1995 found an average reduction in BP of 1.2/1.8 mm Hg with dietary fiber supplements averaging 14 g/d. Fish Oil: A meta‐analysis of 36 RCTs of fish oil supplements, averaging 3.7 g/d, found an overall, statistically significant fall in BP of 2.1/1.6 mm Hg. Antioxidant vitamins: Higher serum levels of vitamins A, C, E, and carotene were associated with increased odds of having hypertension in the NHANES III population. Supplements of vitamin C have sometimes lowered BP and sometimes have had no effects; however, multiple trials with vitamin E supplements have found neither antihypertensive efficacy nor protection against cardiovascular events.

Reduction in Stress

Most studies of various cognitive‐behavioral therapies have shown transient, but not sustained lowering of BP; however, more impressive effects were found in 45 hypertensives who received 10 hours of individualized stress management: after 6 months, ambulatory BP levels were reduced by 6.1/4.3 mm Hg.

Many of the symptoms associated with hypertension are related to anxiety‐induced hyperventilation that may also acutely raise BP. Recognition and control of such hyperventilation can relieve these symptoms. Moreover, slow breathing guided by a device has been found to lower BP.

Avoidance of Sympathomimetic Agents

Acutely, cocaine raises BP often to very high levels that may contribute to severe cardiac damage. Herbal remedies containing ephedra may raise BP. Remedies containing licorice may raise BP by blocking conversion of cortisol to cortisone.

CONCLUSION

In conclusion, the major lifestyle modifications needed to treat hypertension have been defined in the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) and the World Health Organization‐International Society Hypertension (WHO/ISH) guidelines (Table III). Despite the need to rely on lifestyle modifications in hopes of preventing hypertension and in managing the disease once developed, the limited success of achieving significant lifestyle changes in clinical practice must be recognized. For example, a controlled 2‐year trial, despite multiple counseling sessions, accomplished only very small changes in lifestyle, accompanied by only a small fall in BP. Therefore, though lifestyle changes should be pursued, patients must not be denied the proven benefits of antihypertensive drug therapy.