Therapeutic role of exercise in treating hypertension

1. Therapeutic role of exercise in treating hypertension

2. Educational Objectives • To explain the acute blood pressure response to exercise • To list the mechanisms by which exercise may improve hypertension • To apply exercise guidelines in treating hypertension • To prescribe appropriate drug therapy for active hypertensive patients

3. Overview of Hypertension • High BP is a risk factor for stroke, CHF, angina, renal failure, … • 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

4. Classification of Blood Pressure

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 • Exercise moderately each day • Engage in meditation or relaxation daily • Cessation of smoking

11. Blood Pressure classification

12. 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

13. Acute BP Response to Exercise

14. 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

15. 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 J Clin Epidemiol 51 (1): 1998

16. NIH Consensus Conference on Physical Activity and CV Health (1995) • Review of 47 studies of exercise and HTN • 70% of exercise groups decreased SBP by an avg. of 10.5 mm Hg from 154 • 78% of subjects decreased DBP by an avg. of 8.6 mm Hg from 98 • Only 1 study showed increased BP w/ EX • Beneficial responses are 80 times more frequent than negative responses Hagberg, J., et.al., NIH, 1995: 69-71

17. The Pedometer • a small device worn at the waist that counts steps • used successfully in obesity studies

18. PA - A Fountain of Youth Physical inactivity is a primary risk factor Harvard Study:

19. Patient Education Tool

20. 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

21. 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

22. Antihypertensive & Volume Depleting Effects of Mild Exercise on Essential HTN

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

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

26. 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.

27. 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

28. 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 Gordon, N.F., Am J Cardiol 55: 74-78,1985

29. 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

30. 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

31. References Chintanadilok, J., Exercise in Treating Hypertension, PhysSports Med 30: 11-23, 2002 Urata, H., Antihypertensive and Volume-Depleting Effects of Mild Exercise on Essential Hypertension, Hypertension 9: 245-52, 1987. Tanabe, Y., Changes in Serum Concentration of Taurine and Other Amino Acids in Clinical Antihypertensive Exercise Therapy, Clin and Exper Hyper A11: 149-165, 1989. American College of Sports Medicine, Physical Activity, Physical Fitness and Hypertension, Med Sci Sports Exerc 25: i - x , 1993. ACSM’s Resource Manual for Guidelines for Exercise Testing and Prescription, Baltimore, Williams & Wilkins, p. 275-280, 1998.