Therapeutic role of exercise in treating hypertension

Dalynn T. Badenhop, Ph.D., FACSM

Professor of Medicine

Director , Cardiac Rehabilitation

Medical College of Ohio

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

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

1997 JNC VI Classification of Blood Pressure

Blood Pressure Category Systolic Diastolic

Optimal <120 <80

Normal <130 <85

High Normal 130-139 85-89

Hypertension

Stage 1 (Mild) 140-159 90-99

Stage 2 (Moderate) 160-179 100-109

Stage 3 (Severe) > 180 > 110

Overview of HypertensionJoint 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

conditionHigh-normal BP is associated with an incresed

risk of cardiovascular disease N Eng J Med 2001; 345; 1291-7

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

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

Prevalence of Other Risk Factors With Hypertension

Risk Factor Percent

Smoking 35

LDL Cholesterol >140 mg/dl 40

HDL Cholesterol < 40 mg/dl 25

Obesity 40

Diabetes 15

Hyperinsulinemia 50

Sedentary lifestyle >50

Kaplan NM. Dis Mon 1992; 38:769-838

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

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

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

Lifestyle Changes for Hypertension

Reduce excess body weight Reduce dietary sodium to < 2.4 gms/dayMaintain adequate dietary intake of potassium,

calcium and magnesiumLimit daily alcohol consumption to < 2 oz. of

whiskey, 10 oz. of wine, 24 oz. of beerExercise moderately each dayEngage in meditation or relaxation dailyCessation of smoking

JNC VI Blood Pressure Classification

Blood Pressure Stage (mm Hg)

Risk Group A No major risk factors No TOD/CCD

Risk Group B At least one major risk factor, not including DM No TOD/CCD

Risk Group C TOD/CCD and/or DM, with or without other risk factors

High-Normal BP 130-139/85-89

Lifestyle Modification

Lifestyle Modification

Medication Lifestyle Modification

Stage 1 HTN 140-159/90-99

Lifestyle Modification (up to 12 mo)

Lifestyle Modification (up to 6 mo)

Medication Lifestyle Modification

Stage 2,3 HTN ≥160/≥100

Medication

LifestyleModification

Medication

LifestyleModification

Medication

LifestyleModification

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

Acute BP Response to Exercise

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

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

NIH Consensus Conference on Physical Activity and CV Health (1995)

Review of 47 studies of exercise and HTN70% of exercise groups decreased SBP by an

avg. of 10.5 mm Hg from 15478% of subjects decreased DBP by an avg. of

8.6 mm Hg from 98Only 1 study showed increased BP w/ EXBeneficial responses are 80 times more

frequent than negative responsesHagberg, J., et.al., NIH, 1995: 69-71

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

Lifestyle Activity vs.Structured Exercise

JAMA 1999; 281(4): 327-334 moderate-intensity lifestyle activity showed similar or

better results versus structured exercise forimproved cardiovascular fitness reduced body fatdecreased total cholesterolreduced 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

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

Study Design

The Pedometer

a small device worn at the waist that counts steps

used successfully in obesity studies

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

Main Outcome Measures

Blood Pressure and BMIPhysical Activity assessed by:

two questionnairesPhysical Activity Recall Scale (PASE):

assessed activity in past seven daysPhysician-based Assessment and Counseling

for Exercise (PACE) :

assessed readiness for change in level of physical activity

Patient Education Tool

Methods: Patient Identification

Potential subjects identified by chart audit average BP of past three visits in High

Normal BP or Stage 1 HTN categoryExclusion Criteria:

Antihypertensive med use confirmed BP 160/100 Dx DM, CHF, CAD, CVD, CA, MR pregnant child (< 18 yrs)

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

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)

Sample CharacteristicsCategory Group 1(n=7)

(no pedometer)Group 2 (n=13)

(pedometer)Age (M/SD) 61 (14.5) 54 (10)

Race Caucasian Non-Caucasian

61

85

Marital Status married not married

43

85

Income ≥ 40,000$ < 40,000$

15

85

Education high or tech school college graduate

43

76

( / )BMI M SD 31.3 (6) 31.2 (6)

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

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)

Change in Systolic BP from Time 0 to Time 1 (12 weeks) for both groups

P = .005

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

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

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

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

Change in PASE across time for

both groups (24 weeks)

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

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

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

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

Antihypertensive & Volume Depleting Effects of Mild Exercise on Essential HTN

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

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

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

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

Modified Naughton Treadmill Protocol

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 20-30 min/day of continuous activity for first 3 wk, then 30-45 min/day for next 4-6 wk, and 60 min/day as maintenance

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.

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 263:2766-71,1990

Drug Therapy for Active Hypertensive Patients

Hypertension onlyThiazide 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

Drug Therapy for Active Hypertensive Patients

Hypertension with other diseasesCAD - calcium-channel blocker or a beta-

blockerDiabetes - ACE inhibitorLVH but coughs with ACE inhibitor -

angiotensin-2-receptor blockerElderly men with prostatism - peripheral

alpha-blocker (terazosin, doxazosin)

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

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

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: 52-57, 1988

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 MedicineGuidelines for Exercise Testing and Prescription, 2000

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

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: 141-144, 1988

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

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

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.