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Chapter 07
Physical Activity and Hypertension

Hypertension
– is defined in an adult as a blood pressure greater than or equal
to 140 mm Hg systolic pressure or greater than or equal to 90
mm Hg diastolic pressure.
American Heart Association recommended blood
pressure levels
Blood Pressure Category
Systolic (mm Hg)
Normal
less than 120
Pre-hypertension 120–139
High
Stage 1
Stage 2
140–159
160 or higher
or
or
Diastolic (mm Hg)
and
or
less than 80
80–89
90–99
100 or higher
Physical Activity and Hypertension
Hypertension

High blood pressure directly increases the risk of
coronary heart disease (which leads to heart
attack) and stroke, especially when it's
present with other risk factors.


What Causes High Blood Pressure?
In 90 to 95 percent of high blood pressure cases, the
cause is unknown. In fact, you can have high blood
pressure for years without knowing it. That's why it's
the “silent killer” — it creeps up on you. When the cause is
unknown, you have what's called essential or primary
hypertension.
(source = AHA)
Physical Activity and Hypertension
Hypertension.
Magnitude of the Problem
NHANES data - 37.5 million men and 38.8
million women 20 years or older, 33.6% of
noninstitutionalized adults in the United States,
have high blood pressure, defined as untreated
systolic pressure of 140 mmHg or higher, or
diastolic pressure of 90 mmHg or higher,
 The prevalence of hypertension is
disproportionately higher among African
Americans, and it’s lower among Asian
Americans, American Indians or Alaska Natives,
and Mexican American men (see figure 7.2, next
slide).

Physical Activity and Hypertension
Hypertension.
Magnitude of the Problem
Figure 7.2
 High blood pressure in
Americans 20 years of
age or older by sex
and race.

Compared with whites,
blacks develop hypertension
at a younger age and have
higher lifetime blood
pressures, resulting in
elevated relative risks that
are 30% higher for nonfatal
stroke, 80% higher for fatal
stroke, 50% higher for heart
disease mortality, and four
times greater for end-stage
renal disease
Physical Activity and Hypertension
High Blood Pressure Statistics



According to
NHANES, more men
than women have
high blood pressure
until age 45.
From ages 45 to 64,
the rates in men
and women are
similar.
After that, the
percentage of
hypertension is
much higher in
women (see Table
7.2).
Physical Activity and Hypertension
High Blood Pressure Statistics

As with stroke,
obesity, and
diabetes, the
prevalence of
hypertension is
highest in the
southeastern
region of the
United States
(Figure 7.3)
Physical Activity and Hypertension
Hypertension Risk Factors

Controllable risk factors

Obesity — People with a body mass index (BMI) of 30.0 or higher
are more likely to develop high blood pressure.
Eating too much salt — A high sodium intake increases blood
pressure in some people.
Drinking too much alcohol — Heavy and regular use of alcohol
can increase blood pressure dramatically.
Lack of physical activity — An inactive lifestyle makes it easier to
become overweight and increases the chance of high blood
pressure.
Stress — This is often mentioned as a risk factor, but stress levels
are hard to measure, and responses to stress vary from person to
person.




(Source = AHA)
Physical Activity and Hypertension
Hypertension Risk Factors

Uncontrollable risk factors

Race — Blacks develop high blood pressure more often than
whites, and it tends to occur earlier and be more severe.

Heredity — If your parents or other close blood relatives have high
blood pressure, you're more likely to develop it.

Age — In general, the older you get, the greater your chance of
developing high blood pressure. It occurs most often in people
over age 35. Men seem to develop it most often between age 35
and 55. Women are more likely to develop it after menopause.
(Source = AHA)
Physical Activity and Hypertension
Hemodynamic Determinants of Blood
Pressure. Etiology of Hypertension

Central Determinants
– Heart Rate (HR)
– Stroke Volume (SV)
– Cardiac Output (CO)

Peripheral Determinant
– Peripheral Vascular Resistance (PVR)
Physical Activity and Hypertension
Hemodynamic Determinants of Blood
Pressure. Etiology of Hypertension

Central Determinants
– Heart Rate (HR)
 ↑ HR = ↑ BP; ↓HR = ↓ BP
 Factors that ↑ HR = Increased metabolism (CO2 levels
monitored by brainstem in cerebrospinal fluid), Stress (Sympathetic)
Response (↑ epinephrine, norepinephrine), ↑ blood volume,
↑ venous return to the heart = (normal exercise response)
Physical Activity and Hypertension
Hemodynamic Determinants of Blood
Pressure. Etiology of Hypertension

Central Determinants
– Stroke Volume (SV)
 ↑ SV = ↑ BP; ↓SV = ↓ BP
 Factors that ↑ SV = ↑ venous return to the heart =
(normal exercise response, “Frank Starling Effect” ), ↑ contractility
(↑ epinephrine, norepinephrine, also increase with exercise as a
sympathetic response),
Note – Systolic blood pressure increases during
exercise because of an increased HR and SV.
Physical Activity and Hypertension
Hemodynamic Determinants of Blood
Pressure. Etiology of Hypertension

Central Determinants
– Cardiac Output (CO)
 CO = HR X SV
 Anything that ↑ HR and/or SV will ↑CO
 HR measured in beats per minute
 SV measured in milliliters per beat
 CO in measured in Liters per minute
 CO = blood flow
Physical Activity and Hypertension
Hemodynamic Determinants of Blood
Pressure. Etiology of Hypertension

Peripheral Determinant
– Peripheral Vascular Resistance (PVR)
– Is the resistance of the vasculature against the
pumping force generated by the heart
– Is resistance to flow
– Is primarily generated by the diameter of the
artery lumen (space where blood flows through the artery)
Physical Activity and Hypertension
Hemodynamic Determinants of Blood
Pressure. Etiology of Hypertension

Peripheral Determinant
– The smaller the diameter of the artery, the
greater the resistance to flow.
– Thus, PVR is mostly generated by the degree of
vasoconstriction.
– Vasoconstriction is caused by: ↑sympathetic
drive (contraction of the smooth muscle cells in the arterial wall).
This is a normal exercise response, that is
countered by local vasodilatation from aerobic
metabolites. It is not a normal resting response.
Physical Activity and Hypertension
Autonomic Nervous System
Increased sympathetic drive – increasing
levels of epinephrine and norepinephrine
 Effects of epinephrine and norepinephrine
on heart rate and smooth muscle cells in
arteries

– Increase HR, SV, CO and PVR
Physical Activity and Hypertension
Physical Activity and Reduced
Hypertension Risk: The Evidence
Cross Sectional Studies
 North Carolina
– African American Adults
– Odds ratio was 1.3x for inactive women
compared to active women
– After adjusting for other factors, odds ration
was 1.6x
Physical Activity and Hypertension
Physical Activity and Reduced
Hypertension Risk: The Evidence
Cross Sectional Studies
 Southern California
– Caucasian Women
– Age adjusted systolic and diastolic blood
pressure in inactive women were 13 mmHg
systolic and 6 mmHg diastolic higher.
– After adjusting for other factors, there was an
overall linear trend for lower blood pressure
with higher levels of physical activity
Physical Activity and Hypertension
Physical Activity and Reduced
Hypertension Risk: The Evidence
Cross Sectional Studies
 Seventh Day Adventists
– African American subjects
– Age/Sex adjusted systolic and diastolic blood
pressure in inactive subjects were 10 mmHg
systolic and 4 mmHg diastolic higher.
– 42% of non-exercisers compared to 20% of
exercisers were diagnosed as hypertensive.
Physical Activity and Hypertension
Physical Activity and Reduced
Hypertension Risk: The Evidence
Cross Sectional Studies
 Active Commuting in Finland
Four independent cross-sectional surveys of
random national samples in Finland were carried
out at five-year intervals from 1982 to 1997 as
part of the Finnish cohort of the WHO MONICA
study. Stratified by sex and 10-year age
categories, high leisure-time physical activity but
not activity for commuting was associated with
lower DBP among both men and women.
Physical Activity and Hypertension
Physical Activity and Reduced
Hypertension Risk: The Evidence
Cross Sectional Studies
 Active Commuting in CARDIA
Associations were examined between walking or biking to
work (self-reported time, distance, and mode of
commuting) with cardiorespiratory fitness, leisure-time
physical activity
Men with any active commuting, compared to none, had a
50% reduction in odds of having a BMI ≥30 and had a
DBP that was nearly 2 mmHg lower than in people who
did not walk or bicycle to work
Physical Activity and Hypertension
Physical Activity and Reduced
Hypertension Risk: The Evidence
Prospective Cohort Studies
 Aerobics Center Longitudinal Study
– Relative risk for developing hypertension was
1.5 for the lowest fitness group
– The lowest fitness group who had normal
systolic and diastolic pressures had 10x the
risk of developing hypertension than those
that were highly fit and had normal blood
pressures.
Physical Activity and Hypertension
Physical Activity and Reduced
Hypertension Risk: The Evidence
Prospective Cohort Studies
 Aerobics Center Longitudinal Study
– People who moved from the lowest fitness
group to the highest fitness group had about
½ the risk of developing hypertension of
those who remained in the low fitness group
Physical Activity and Hypertension
Physical Activity and Reduced
Hypertension Risk: The Evidence
Prospective Cohort Studies
 Harvard Alumni Health Study
– Those who expended less than 2000 kcal/wk
had a 30% greater risk of developing
hypertension than those who expended more
than 2000 kcal / wk
– There was an inverse relationship between
participation in vigorous recreational sports in
middle age and the risk of developing
hypertension.
Physical Activity and Hypertension
Physical Activity and Reduced
Hypertension Risk: The Evidence
Prospective Cohort Studies
 University of Pennsylvania Alumni Study
– Those who spent less than 5 hours per week
in sports participation had a 30% greater risk
of developing hypertension.
– Participation in vigorous recreational sports
activity in middle age reduced the rate of
hypertension
Physical Activity and Hypertension
Physical Activity and Reduced
Hypertension Risk: The Evidence
Prospective Cohort Studies
 Iowa Women Study
– The relative risk of developing hypertension
was 30% higher in women in the lowest
active group compared to the most active
group
Physical Activity and Hypertension
Physical Activity and Reduced
Hypertension Risk: The Evidence
Prospective Cohort Studies
 The Northwestern Trial
– The incidence of hypertension in the control
group (Sedentary) was 2x that of the
intervention group.
– Other intervention behaviors were not
controlled, so the independent effect of
exercise could not be measured.
– Study showed the effectiveness of nonpharmacological intervention.
Physical Activity and Hypertension
Physical Activity and Reduced
Hypertension Risk: The Evidence
Prospective Cohort Studies – Youth Studies
 New York City
A cohort of nearly 200 mainly Hispanic 5-year-olds
who regularly visited an inner-city medical
center was followed for 20 months . Age-related
increases in blood pressure were inversely
related to higher fitness. Children in the top
20% of fitness gains had a significantly smaller
increase in SBP (3 mmHg per year) compared to
children in the lowest 20% of fitness gains (5
mmHg per year).
Physical Activity and Hypertension
Physical Activity and Reduced
Hypertension Risk: The Evidence
Prospective Cohort Studies – Youth Studies
 The Northern Ireland Young Hearts
Project
Cardiovascular risk factors were assessed in a random
cohort of 229 boys and 230 girls when they were 12
years old and again when they were age 15. There was
a significant relation between self-reports of physical
activity and lower SBP over the three-year period among
boys but not girls
Physical Activity and Hypertension
Physical Activity and Treatment of
Hypertension : The Evidence
Strength of the Evidence
 Summary:
– Regular exercise decreases blood pressure;
(SBP -11 mmHg ), (DBP -8 mmHg)
– People with mild hypertension benefited more
than those with more severe hypertension
– Women had larger reductions than men
(W=SBP -19; DBP -7 ) (M=SBP – 14; -5
mmHg)
Physical Activity and Hypertension
Physical Activity and Treatment of
Hypertension : The Evidence
Strength of the Evidence
 Summary:
– Consistent reductions in BP were found in studies that set
exercise intensity below 75% VO2 max
– The reductions in DBP were greater the longer the exercise
training program lasted
– People with mild hypertension benefited more than those
diagnosed with severe hypertension or those with normal blood
pressures.
– Subsequent research has shown that men with severe
hypertension can benefit from exercise intervention, and reduce
Left Ventricular Hypertrophy
Physical Activity and Hypertension
Physical Activity and Treatment of
Hypertension : The Evidence
Strength of the Evidence
 Summary:
– A newer meta-analysis (See Figure 7.8, next slide) accumulated
results of 72 randomized controlled trials of 3936 participants in
105 study groups who exercised mainly by walking, jogging,
running, or cycling for at least four weeks
– exercise training reduced systolic and diastolic pressures
measured in a clinic by 3 mmHg and 2.4 mmHg, respectively
– The reduction of resting blood pressure was more pronounced in
30 groups of patients with mainly stage 1 hypertension (−6.9
mmHg systolic and −4.9 mmHg diastolic) than in normotensive
groups (−1.9/−1.6 mmHg)
Physical Activity and Treatment of
Hypertension : The Evidence
Figure 7.8
Cumulative results of 72
randomized controlled trials
of chronic exercise and
hypertension.
Physical Activity and Treatment of
Hypertension : The Evidence
Strength of the Evidence
 Summary of additional interventions
– A meta-analysis of 105 trials of lifestyle interventions lasting at
least eight weeks on nearly 7000 adults with elevated blood
pressure found that aerobic exercise compared favorably to dietary
changes, as shown in Table 7.3. The evidence did not support the
use of relaxation therapies or calcium, magnesium, or potassium
supplements to reduce blood pressure
Strength Of The Evidence

Temporal Sequence
– Large cohort studies show lowered risk of
developing hypertension following exercise

Strength of the Association
– Collective findings show a 30-50% reduction
in risk when active are compared to inactive

Consistency
– Physical activity reduces blood pressure
regardless of age, sex, or race.
Physical Activity and Hypertension
Strength Of The Evidence

Dose Response
– No evidence of an intensity dose response;
however, there is an effective intensity range
– This range was 30-85% aerobic capacity
– Duration of exercise 15-60 minutes
– Frequency of exercise 3-4x / week, for at
least four weeks.
Physical Activity and Hypertension
Strength Of The Evidence

Biological Plausibility
– Possibly a reduction in plasma volume that decreases
resting cardiac output
– A reduction in resting catecholamines suggest that
exercise training decreases the sympathetic drive
lowering blood pressure via decreased HR and PVR
– There is a relationship between blood insulin levels
and hypertension, thus weight loss can promote a
reduction in hypertension by reducing
hyperinsulinemia
– There may be a blunted sympathetic response to
external stressors following exercise intervention
Physical Activity and Hypertension
END OF PRESENTATION
Physical Activity and Hypertension