Transcript Therapeutic role of exercise in treating hypertension

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
Optimal
Normal
High Normal
Hypertension
Stage 1 (Mild)
Stage 2 (Moderate)
Stage 3 (Severe)
Systolic
<120
<130
130-139
Diastolic
<80
<85
85-89
140-159
160-179
> 180
90-99
100-109
> 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 agerelated 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
Smoking
LDL Cholesterol >140 mg/dl
HDL Cholesterol < 40 mg/dl
Obesity
Diabetes
Hyperinsulinemia
Sedentary lifestyle
Percent
35
40
25
40
15
50
>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/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
Medical Therapy and
Implications for Exercise Training
Pharmacologic and nonpharmocologic
treatment can reduce morbidity
Some antihypertensive agents have sideeffects 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
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
Duration
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 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
Drug Therapy for Active
Hypertensive Patients
Hypertension with other diseases
CAD - calcium-channel blocker or a betablocker
Diabetes - ACE inhibitor
LVH but coughs with ACE inhibitor angiotensin-2-receptor blocker
Elderly 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 Betablocker 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