drugs & exercise for treating hypertension & heart disease

Drugs & Exercise for Treating Hypertension & Heart Disease

Chapter 12

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

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

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

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

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

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

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

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

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


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)


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

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


Exercise therapy is desirable during Beta-blocker therapy to offset the adverse alterations in lipoprotein metabolism contributed by some Beta-blocker medications


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


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


Patients treated with Beta-blockers are capable of deriving the expected enhancement of cardiorespiratory fitness during training, irrespective of the type of drug used

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

drugs & exercise for treating hypertension & heart disease

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