This is an excerpt from Clinical Exercise Physiology 4th Edition With Web Resource by Jonathan Ehrman,Paul Gordon,Paul Visich & Steven Keteyian.
The overarching goal in the treatment, control, and management of hypertension is to reduce the risk of CVD morbidity and mortality. Target BP levels may be achieved through lifestyle modification alone or in combination with pharmacological treatment. In general, the traditionally accepted BP goal for most individuals with hypertension is <130/80 mmHg. However, this goal may vary based on the presence of other comorbid conditions, overall CVD risk, 10-yr atherosclerotic cardiovascular disease (ASCVD) risk, and individual clinician approaches to BP control. Furthermore, there is a lack of consensus and considerable controversy among professional organizations regarding the threshold with which to treat and control BP. For individuals with hypertension, the JNC 7 guidelines previously recommended a goal BP of <140/90 mmHg for the general population and <130/80 mmHg in patients with coexisting diabetes mellitus or CKD. The most recent 2017 ACC/AHA guidelines recommend a goal BP of <130/80 mmHg.
The 2017 ACC/AHA departure from the traditional and longstanding treatment recommendations was in part due to the results of the Systolic Blood Pressure Intervention (SPRINT) trial. SPRINT was a randomized trial of patients (n = 9,361) ≥50 yr with prehypertension and high CVD risk that assigned patients to a standard treatment group (target systolic BP of <140 mmHg) or an intensive treatment group (target systolic BP of <120 mmHg). Among individuals in the intensive treatment group, there was a substantial reduction in CVD-related events by 25% and death by 43% after achieving an overall systolic BP of 122 mmHg in ~3.3 yr. Taken altogether, the findings from SPRINT and other recent reports have challenged the previous BP threshold for treatment by providing evidence to support a target systolic BP ~15% lower than the recommended level of 140/90 mmHg. Although preliminary, the landmark SPRINT study has spearheaded an international call to action to reappraise BP treatment thresholds and may very well inform future evidence-based guidelines. In the meantime, the 2017 ACC/AHA guidelines emphasize that published guidelines should not be a substitute for good clinical judgment, and treatment should be individualized to the patient with the goal of reducing overall CVD risk.
Adoption of a healthy lifestyle is essential for the primary prevention, treatment, and control of hypertension. Lifestyle modifications are advocated as a first line of defense to treat and control high BP among individuals with hypertension. In addition, when lifestyle modifications are executed appropriately, additional coexisting CVD risk factors may experience benefit, translating to an even greater reduction in overall CVD risk. Furthermore, the relationship between BP and CVD risk is linear, continuous, and consistent starting at 115/75 mmHg. Because patients with elevated BP are particularly vulnerable to developing future hypertension, early and aggressive lifestyle intervention is critical in order to prevent or delay the rapid, progressive rise in BP. Table 9.6 provides lifestyle modifications recommended by the ACC/AHA for the treatment of hypertension.
Individuals who are overweight or obese are 2 to 2.5 times more likely to have hypertension than individuals who are normal weight, and it has been estimated that 78% of the risk for developing hypertension in men and 65% of the risk for women is attributed to excess body mass. Weight loss of as little as 1 kg corresponds to reductions in systolic BP of 1.2 mmHg and diastolic BP of 1.0 mmHg; these reductions are time and dose dependent, such that greater BP reductions are experienced with greater weight loss. Weight reduction can also enhance the effects of antihypertensive medications and positively affect other CVD risk factors or conditions such as diabetes mellitus and dyslipidemia. For these reasons, the ACSM emphasizes the importance of increased caloric expenditure coupled with reduced caloric intake in individuals who are overweight or obese with hypertension to facilitate weight reduction and the resultant reductions in BP.
Dietary modifications such as the Dietary Approaches to Stop Hypertension (DASH) diet (i.e., a plant-focused diet rich in fruits, vegetables, nuts, whole grains, low-fat and nonfat dairy, lean meats, fish, poultry, and heart-healthy fats) and sodium restriction can reduce BP by 2 to 14 mmHg. High dietary salt causes hypertension in about 30% of those with high BP. Individuals with hypertension may be classified as salt sensitive and salt resistant, based on the absolute changes in BP that originate from dietary salt intake. African Americans, older adults, and individuals with hypertension or diabetes are more sensitive to changes in dietary sodium than are others in the general population. The 2017 ACC/AHA guidelines recommend <1,500 mg/d as an optimal goal but suggest to aim for at least 1,000 mg/d for most adults.
Excessive alcohol consumption is a risk factor for hypertension, and reducing alcohol intake can reduce BP from 2 to 4 mmHg. It is recommended that men limit their daily intake to no more than 1 oz (30 mL) of ethanol and women and lighter-weight individuals limit their daily intake to no more than 0.5 oz (15 mL). These quantities are equivalent to two drinks per day in most men and one drink per day in women. One drink is defined as 12 oz (360 mL) of beer, 5 oz (150 mL) of wine, or 1.5 oz (45 mL) of 80-proof liquor.
Finally, regular aerobic exercise can reduce BP by 5 to 7 mmHg among individuals with hypertension; these BP reductions rival the magnitude of those obtained with first-line antihypertensive medications and lower CVD risk by 20% to 30%. Exercising as little as 1 d/wk is as effective (or even more so) than pharmacotherapy for reducing all-cause mortality among those with hypertension. Furthermore, a recent meta-analysis of major exercise and drug trials showed no statistically detectable difference between exercise and drug interventions for coronary heart disease and prediabetes, and physical activity interventions were more effective than drug interventions for the secondary prevention of stroke mortality. The optimal exercise prescription for the primary prevention and treatment of hypertension is discussed in detail later in this chapter.
When lifestyle interventions are not effective in achieving treatment BP goals, the decision to initiate antihypertensive therapy should be guided by the presence of disease (i.e., CVD, diabetes mellitus, or CKD), and 10-yr risk for heart disease and stroke as assessed by the ASCVD risk calculator according to the 2017 ACC/AHA treatment algorithm (table 9.1). Specifically, ACC/AHA endorses the following recommendations for the management of hypertension in adults:
- In adults with systolic BP 130-139 mmHg or diastolic BP 80-89 mmHg (i.e., hypertension stage 1), assess the 10-yr risk for ASCVD. If risk is <10%, start with healthy lifestyle recommendations and reassess in 3-6 mo.
- If risk is ≥10% or the patient has known clinical CVD, diabetes mellitus, or CKD, recommend lifestyle changes and BP-lowering medication and reassess in 1 mo for effectiveness of medication therapy.
- In adults with systolic BP ≥140 mmHg or ≥90 mmHg (i.e., hypertension stage 2), recommend healthy lifestyle changes and BP-lowering medication (2 medications of different classes).
- If BP goal is met after 1 mo, reassess in 3-6 mo. If goal is not met after 1 mo, consider different medication or titration. Continue monthly follow-up until control is achieved (i.e., <130/80mmHg).
Most individuals who require treatment for hypertension require two or more antihypertensive medications to achieve goal BP. If goal BP is not achieved within a month of treatment, it is recommended to increase the dose of the initial drug or add a second class of drug. The clinician should continue to adjust the treatment regimen until goal BP is reached. If a goal BP cannot be achieved with two drugs, a third drug of a different medication class, such as β-blocker or aldosterone antagonist, should be added. Individuals who cannot achieve a goal BP despite the concurrent use of three antihypertensive agents of different classes, including a diuretic, may require a hypertension specialist because resistant hypertension is almost always multifactorial in etiology. Successful treatment of resistant hypertension requires appropriate lifestyle modifications, diagnosis, and appropriate treatment of secondary causes of hypertension and use of effective multidrug regimens. In cases of treatment-resistant hypertension, the importance of drug adherence should be assessed and discussed with patients, as a portion of treatment-resistant hypertension cases may be attributed to suboptimal adherence to antihypertensive drug therapy.
After initiation of drug therapy, most patients should return for follow-up and adjustment of medications at approximately monthly intervals until the goal BP is reached (table 9.4). Follow-up visits should be at 3 to 6 mo intervals after BP is at goal, with more frequent follow-up among patients with stage 2 hypertension or with complicated comorbid conditions. Serum potassium and creatinine should be monitored at least once or twice per year. Many antihypertensive medications affect the physiological response to exercise and should be taken into consideration during exercise testing and training (table 9.4). Furthermore, lifestyle modifications such as exercise should be encouraged and continued during antihypertensive therapy. Therefore, understanding potential interactions between lifestyle interventions and antihypertensive therapy is important to guide clinical care. For example, antihypertensive medications in conjunction with exercise facilitate greater improvements in health outcomes and risk factors than with exercise alone. Clinicians must weigh the benefit of antihypertensive medication alone, and in combination with lifestyle modifications, in order to tailor an individualized treatment plan.