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Therapeutic role of exercise in treating hypertension

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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
Blood Pressure Category Systolic Diastolic Optimal <120 <80 Normal <130 <85 High Normal 85-89 Hypertension Stage 1 (Mild) 90-99 Stage 2 (Moderate) Stage 3 (Severe) > 180 > 110

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;

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
Percent Smoking 35 LDL Cholesterol >140 mg/dl 40 HDL Cholesterol < 40 mg/dl 25 Obesity Diabetes 15 Hyperinsulinemia 50 Sedentary lifestyle >50 Kaplan NM. Dis Mon 1992; 38:

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 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 , 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 Medical College of Ohio Study Group
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): 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 Physician
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

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 20 subjects with HTN (155/100) randomized to Exercise or Control group
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: ,1987

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

43 Change in serum Na+:serum K+ positively correlated with change in SBP
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 & BLAT during GXT’s were reduced Change in resting NE correlated with change in mean BP Urata, H., et. al. Hypertension 9: , 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: , 1989

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

46

47 Exercise Prescriptions for Patients With Borderline-to-Moderate Hypertension
Patient evaluation Look for lipid disorders, DM, retinopathy, neuropathy, PVD, renal insufficiency, LV dysfunction, silent MI/ischemia osteoarthritis, osteoporosis Exercise testing GXT with modified Naughton protocol, R/O asymptomatic ischemic CAD, radionuclide Exercise type Aerobic, low-impact activities: walking, biking, swimming, tai chi, stepper, treadmill walking

48 Modified Naughton Treadmill Protocol

49 Exercise Prescriptions for Patients With Borderline-to-Moderate Hypertension
Frequency 5 days/week as a minimum Intensity Start at 50-60% maximum HRR & slowly increase to 70%; within 6 weeks work at 85% HRR or from 50-90% of maximal heart rate Duration Start with min/day of continuous activity for first 3 wk, then min/day for next 4-6 wk, and 60 min/day as maintenance

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.

51 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 Kelemen, et.al., JAMA 263: ,1990

52 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

53 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)

54 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 Kaplan, N.M., Am J Hypertens 2:75-77,1989

55 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: ,1985

56 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 Gordon, N.F., Compr Ther 14: , 1988

57 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. American College of Sports Medicine Guidelines for Exercise Testing and Prescription, 2000

58 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. Kaplan, N.M., Am J Hypertens 2:75-77,1989

59 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 Blood, S.M., J Cardiopulmonary Rehabil 8: , 1988

60 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

61 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

62 References Chintanadilok, J., Exercise in Treating Hypertension, PhysSports Med 30: , 2002 Urata, H., Antihypertensive and Volume-Depleting Effects of Mild Exercise on Essential Hypertension, Hypertension 9: , 1987. Tanabe, Y., Changes in Serum Concentration of Taurine and Other Amino Acids in Clinical Antihypertensive Exercise Therapy, Clin and Exper Hyper A11: , 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 , 1998.


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