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
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
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
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
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
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
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
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
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