Therapeutic role of exercise in treating hypertension

1. Therapeutic role of exercise in treating hypertension Dalynn T. Badenhop, Ph.D., FACSM Professor of Medicine Director , Cardiac Rehabilitation Medical College of Ohio

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, 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

4. 1997 JNC VI Classification of Blood Pressure

5. Overview of Hypertension • Joint National Committee VI (JNC VI) on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (1997) • 50 million hypertensive patients in the U.S. • National Health and Nutrition Examination Survey III (NHANES III) (1995) • only 21% of treated hypertensive patients have BP controlled to <140/90 mm Hg • 35% of hypertensive patients are unaware of their condition • High-normal BP is associated with an incresed risk of cardiovascular disease • N Eng J Med 2001; 345; 1291-7

6. 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

7. 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

8. Prevalence of Other Risk Factors With Hypertension Kaplan NM. Dis Mon 1992; 38:769-838

9. 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

10. 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

11. 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

12. 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

13. JNC VI Blood Pressure Classification

14. 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

15. Acute BP Response to Exercise

16. 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

17. 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

18. 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

19. Increasing Lifestyle Activity for Patients with High-Normal Blood Pressure and Stage I Hypertension Medical College of Ohio Study Group Kevin A. Phelps, D.O. Larry Johnson, M.D. Sandra Puczynski, Ph.D. Dalynn Badenhop, Ph.D. Michael McCrea Wendy Boone, RN, M.P.H

20. Lifestyle Activity vs.Structured Exercise • JAMA 1999; 281(4): 327-334 • moderate-intensity lifestyle activity showed similar or better results versus structured exercise for • improved cardiovascular fitness • reduced body fat • decreased total cholesterol • reduced blood pressure • patient compliance • In the past five years the Surgeon General, CDC, NIH, and ACSM have published position statements on the potential health benefits of lifestyle activity

21. Study Design • Twenty-four week, physician-directed intervention program to lower BP by increasing physical activity • Patients randomized into two groups: • Group 1 - educational intervention monitored via activity logs • Group 2 - educational intervention monitored via activity logs and pedometer

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

23. Study Hypotheses • Adding a pedometer • to goal setting will increase the level and frequency of physical activity • will improve BP control of adult patients with high-normal BP or Stage 1 HTN

24. Main Outcome Measures • Blood Pressure and BMI • Physical Activity assessed by: • two questionnaires • Physical Activity Recall Scale (PASE): assessed activity in past seven days • Physician-based Assessment and Counseling for Exercise (PACE) : assessed readiness for change in level of physical activity

25. Patient Education Tool

26. Methods: Patient Identification • Potential subjects identified by chart audit • average BP of past three visits in High Normal BP or Stage 1 HTN category • Exclusion Criteria: • Antihypertensive med use • confirmed BP ³160/100 • Dx DM, CHF, CAD, CVD, CA, MR • pregnant • child (< 18 yrs)

27. Methods: Patient Recruitment • Identified subjects contacted during regularly scheduled physician visit • Physician introduced study to patient • Interested patients met with research assistant for more information about study

28. Methods: Patient Eligibility • Interested patients had two eligibility visits two weeks apart to confirm elevated BP • If average BP at two visits confirmed High-Normal BP or Stage 1 HTN from chart audit, then patient was scheduled for first study visit (t0)

29. Sample Characteristics

30. Methods: Study Visits • Research Assistant • measured BP and weight, reviewed activity log at all visits • administered PASE and PACE at baseline and completion • Physician • discussed barriers to increasing activity • new activity goal setting • assisted with problem solving

31. Preliminary Results • Outcome measures analyzed at • beginning of study, week 0 (t0) • end of intervention period, week 12 (t1) • end of maintenance period, week 24 (t2)

32. Change in Systolic BP from Time 0 to Time 1 (12 weeks) for both groups P = .005

33. Change in Systolic BP across time for both groups (24 weeks)

34. Change in Diastolic BP from Time 0 to Time 1 for both groups (12 weeks)

35. Change in Diastolic BP across time for both groups (24 weeks)

36. Change in BMI across time for both groups (24 weeks)

37. Change in PASE across time for both groups (24 weeks)

38. Preliminary Conclusions • Intervention alone (Group 1) did not significantly improve BP • Intervention plus a pedometer (Group 2) significantly improved BP, but only with regular physician visits

39. 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

40. 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

41. Antihypertensive & Volume Depleting Effects of Mild Exercise on Essential HTN • 20 subjects with HTN (155/100) randomized to Exercise or Control group • Cycle Ergometer Exercise at Blood Lactic Acid Threshold for 60 min. 3X/wk for 10 weeks • Changes in BP, hemodynamics and humoral factors of EX group compared with control group Urata, H., et. al. Hypertension 9:245-252,1987

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

43. Antihypertensive & Volume Depleting Effects of Mild Exercise on Essential HTN • Whole blood and plasma volume indices were significantly reduced (p < 0.05) • Change in serum Na+:serum K+ positively correlated with change in SBP • Plasma NE concentrations at rest & Workload @ BLAT during GXT’s were reduced • Change in resting NE correlated with change in mean BP Urata, H., et. al. Hypertension 9:245-252, 1987

44. Changes in Taurine & other Amino Acids in Response to Mild Exercise • Blood pressures were significantly decreased by 14.8/6.6 mmHg in the EX group but not the Control group • Serum concentration increases of taurine (26%), cystine (287%), asparagine (11%), histidine (6%) and lysine (7%) in the EX • Serum taurine was negatively correlated with the change in plasma NE Tanabe, Y, et. al., Clin & Exper Hyper 11:149-165, 1989

45. Changes in Taurine & other Amino Acids in Response to Mild Exercise

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

48. Modified Naughton Treadmill Protocol

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

50. 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.