Therapeutic role of exercise in treating hypertension

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, …

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

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

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

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 magnesiumExercise moderately each dayEngage in meditation or relaxation dailyCessation of smoking

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 Lifestyle Modification

Medication Lifestyle Modification

Medication Lifestyle Modification

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

The Pedometer

a small device worn at the waist that counts steps

used successfully in obesity studies

PA - A Fountain of YouthPhysical inactivity is a primary risk

factorHarvard Study:

Patient Education Tool

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

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

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

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

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.