Drugs & Exercise for Treating Hypertension & Heart Disease

1. Drugs & Exercise for Treating Hypertension & Heart Disease Chapter 12

2. Overview of Hypertension • High BP is a risk factor for stroke, CHF, angina, renal failure, LVH and MI • Hypertension clusters with hyperlipidemia, diabetes and obesity • Drugs have been effective in treating high BP but because of their side effects and cost, non-pharmacologic alternatives are attractive

3. Classification of Blood Pressure

4. Pathophysiology of Hypertension • Essential hypertension is characterized by increased DBP and related arteriolar vasoconstriction leading to increased SBP • BP is mainly determined by cardiac output and total peripheral resistance • High blood pressure may be linked to age-related vascular stiffening

5. Pathophysiology of Hypertension • High blood pressure is also associated with obesity, salt intake, low potassium intake, physical inactivity, heavy alcohol use and psychological stress • Intra-abdominal fat and hyperinsulinemia may play a role in the pathogenesis of hypertension

6. Prevalence of Other Risk Factors With Hypertension

7. Cardiovascular Consequences of Hypertension • Individuals with BP > 160/95 have CAD, PVD & stroke that is 3X higher than normal • HTN may lead to retinopathy and nephropathy • HTN is also associated with subclinical changes in the brain and thickening and stiffening of small blood vessels

8. Cardiovascular Consequences of Hypertension • Increased cardiac afterload leads to left ventricular hypertrophy and reduced early diastolic filling • Increased LV mass is positively associated with CV morbidity and mortality independent of other risk factors • High BP also promotes coronary artery calcification, a predictor of sudden death

9. Hypertension & CVD Outcomes • Increased BP has a positive and continuous association with CV events • Within DBP range of 70-110 mm Hg, there is no threshold below which lower BP does not reduce stroke and CVD risk • A 15/6 mm Hg BP reduction reduced stroke by 34% and CHD by 19% over 5 years

10. Lifestyle Changes for Hypertension • Reduce excess body weight • Reduce dietary sodium to < 2.4 gms/day • Maintain adequate dietary intake of potassium, calcium and magnesium • Limit daily alcohol consumption to < 2 oz. of whiskey, 10 oz. of wine, 24 oz. of beer • Exercise moderately each day • Engage in meditation or relaxation daily • Cessation of smoking

11. Medical Therapy and Implications for Exercise Training • Pharmacologic and nonpharmocologic treatment can reduce morbidity • Some antihypertensive agents have side-effects and some worsen other risk factors • Exercise and diet improve multiple risk factors with virtually no side-effects • Exercise may reduce or eliminate the need for antihypertensive medications

12. Exaggerated BP Response to Exercise • Among normotensive men who had an exercise test between 1971-1982, those who developed HTN in 1986 were 2.4 times more likely to have had an exaggerated BP response to exercise • Exaggerated BP response increased future hypertension risk by 300% after adjusting for all other risk factors

13. Exaggerated BP Response to Exercise • Exaggerated BP was change from rest in SBP >60 mm Hg at 6 METs; SBP > 70 mm Hg at 8 METs; DBP > 10 mm Hg at any workload. • Subjects in CARDIA study with exaggerated exercise BP were 1.7 times more likely to develop HTN 5 years later

14. Possible Mechanisms of BP Reduction with Exercise • Reduced visceral fat independent of changes in body weight or BMI • Altered renal function to increase elimination of sodium leading to reduce fluid volume • Anthropomorphic parameters may not be primary mechansims in causing HTN

15. Possible Mechanisms of BP Reduction with Exercise • Lower cardiac output and peripheral vascular resistance at rest and submaximal exercise • Decreased HR • Decreased sympathetic and increased parasympathetic tone • Lower blood catecholamines and plasma renin activity

17. Exercise Prescriptions for Patients With Borderline-to-Moderate Hypertension

18. Exercise Prescriptions for Patients With Borderline-to-Moderate Hypertension • Excessive rises in blood pressure should be avoided during exercise (SBP > 230 mm Hg; DBP > 110 mm Hg). Restrictions on participation in vigorous exercise should be placed on patients with left ventricular hypertrophy.

19. Weight Training • Resistive exercise produces the most striking increases in BP • Resistive exercise results in less of a HR increase compared with aerobic exercise and as a result the “rate pressure product” may be less than aerobic exercise • Assessment of BP response by handgrip should be considered in patients w/ HTN • Growing evidence that resistive training may be of value for controlling BP

20. Drug Therapy for Active Hypertensive Patients Hypertension only • Thiazide diuretics in combination with a potassium supplement are effective and inexpensive • Diuretics limit plasma volume expansion and decrease peripheral resistance • Other antihypertensive drugs can be used as monotherapy for this type of patient

21. Drug Therapy for Active Hypertensive Patients Hypertension with other diseases CAD - calcium-channel blocker or a beta- blocker Diabetes - ACE inhibitor LVH but coughs with ACE inhibitor - angiotensin-2-receptor blocker Elderly men with prostatism - peripheral alpha-blocker (terazosin, doxazosin)

22. Drug Therapy for Active Hypertensive Patients • Beta1-selective blockers such as atenolol or metoprolol are preferable to non-selective agents such as propranolol, nadolol or pindolol for hypertensive patients engaged in regular exercise

23. Beta-blocker therapy and exercise • Non-selective Beta-blockers may increase a patient’s disposition to exertional hyperthermia. So patients should adhere strictly to guidelines for fluid replacement • Patients should use fluid replacement drinks with low concentrations of K+ to avoid the risk of hypokalemia

24. Beta-blocker therapy and exercise • Exercise therapy is desirable during Beta-blocker therapy to offset the adverse alterations in lipoprotein metabolism contributed by some Beta-blocker medications

25. Beta-blocker therapy and exercise • Exercise intensity for patients on Beta-blocker medications should be in accordance with traditional guidelines based on the results of individualized exercise testing performed on the medication

26. Beta-blocker therapy and exercise • Non-selective Beta-blockers dramatically reduce peak aerobic capacity and at the same time increase a patient’s rating of perceived exertion for a given amount of work

27. Beta-blocker therapy and exercise • Patients treated with Beta-blockers are capable of deriving the expected enhancement of cardiorespiratory fitness during training, irrespective of the type of drug used

28. SUMMARY • Physical activity has a therapeutic role in the treatment of hypertension • No consistent relationship between reduced weight and lower BP • Exercise at lower intensities is effective in treating mild to moderate hypertension • Exercise testing may help identify exaggerated BP responses to exercise

29. SUMMARY • Exercise prescription for HTN should be based on medical hx and risk factor status • Exercise prescription should be adapted to antihypertensive medications that may affect exercise HR, BP & performance • Incorporating resistive training into the exercise prescription may be of value for controlling blood pressure