Chapter 07

Chapter 07Chapter 07

Physical Activity and Physical Activity and HypertensionHypertension

Physical Activity and HypertensionPhysical 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) Diastolic (mm

Hg) Normal less than 120 and less than 80Pre-hypertension 120–139 or 80–89 HighStage 1 140–159 or 90–99Stage 2 160 or higher or 100 or higher


HypertensionHypertension High blood pressure directly increases the High blood pressure directly increases the

risk of coronary heart disease (which leads risk of coronary heart disease (which leads to heart attack) and stroke, especially when to heart attack) and stroke, especially when it's present with other risk factors. it's present with other risk factors.

What Causes High Blood Pressure?What Causes High Blood Pressure? In 90 to 95 percent of high blood pressure cases, In 90 to 95 percent of high blood pressure cases,

the cause is unknown. In fact, you can have high the cause is unknown. In fact, you can have high blood pressure for years without knowing it. That's blood pressure for years without knowing it. That's why it's the “silent killer” — it creeps up on you. why it's the “silent killer” — it creeps up on you. When the cause is unknown, you have what's called When the cause is unknown, you have what's called essential or primary hypertension. essential or primary hypertension.

(source = AHA)(source = AHA)


Hypertension. Hypertension. Magnitude of the ProblemMagnitude of the Problem

NHANES data - 37.5 million men and 38.8 NHANES data - 37.5 million men and 38.8 million women 20 years or older, 33.6% of million women 20 years or older, 33.6% of noninstitutionalized adults in the United noninstitutionalized adults in the United States, have high blood pressure, defined States, have high blood pressure, defined as untreated systolic pressure of 140 as untreated systolic pressure of 140 mmHg or higher, or diastolic pressure of mmHg or higher, or diastolic pressure of 90 mmHg or higher, 90 mmHg or higher,

The prevalence of hypertension is The prevalence of hypertension is disproportionately higher among African disproportionately higher among African Americans, and it’s lower among Asian Americans, and it’s lower among Asian Americans, American Indians or Alaska Americans, American Indians or Alaska Natives, and Mexican American men (see Natives, and Mexican American men (see figure 7.2, next slide).figure 7.2, next slide).


Hypertension. Hypertension. Magnitude of the ProblemMagnitude of the Problem

Figure 7.2 Figure 7.2 High blood pressure High blood pressure in Americans 20 years in Americans 20 years of age or older by sex of age or older by sex and race.and race.Compared with whites, Compared with whites, blacks develop hypertension blacks develop hypertension at a younger age and have at a younger age and have higher lifetime blood higher lifetime blood pressures, resulting in pressures, resulting in elevated relative risks that elevated relative risks that are 30% higher for nonfatal are 30% higher for nonfatal stroke, 80% higher for fatal stroke, 80% higher for fatal stroke, 50% higher for heart stroke, 50% higher for heart disease mortality, and four disease mortality, and four times greater for end-stage times greater for end-stage renal disease renal disease


High Blood Pressure High Blood Pressure StatisticsStatistics

According to According to NHANES, more NHANES, more men than women men than women have high blood have high blood pressure until pressure until age 45. age 45.

From ages 45 to From ages 45 to 64, the rates in 64, the rates in men and women men and women are similar. are similar.

After that, the After that, the percentage of percentage of hypertension is hypertension is much higher in much higher in women (see women (see Table 7.2). Table 7.2).


High Blood Pressure High Blood Pressure StatisticsStatistics

As with stroke, As with stroke, obesity, and obesity, and diabetes, the diabetes, the prevalence of prevalence of hypertension hypertension is highest in is highest in the the southeastern southeastern region of the region of the United States United States (Figure 7.3)(Figure 7.3)


Hypertension Risk Hypertension Risk FactorsFactors

Controllable risk factorsControllable risk factors

ObesityObesity — People with a body mass index (BMI) of 30.0 or — People with a body mass index (BMI) of 30.0 or higher are more likely to develop high blood pressure. higher are more likely to develop high blood pressure.

Eating too much saltEating too much salt — A high sodium intake increases — A high sodium intake increases blood pressure in some people. blood pressure in some people.

Drinking too much alcoholDrinking too much alcohol — Heavy and regular use of — Heavy and regular use of alcohol can increase blood pressure dramatically. alcohol can increase blood pressure dramatically.

Lack of physical activityLack of physical activity — An inactive lifestyle makes it — An inactive lifestyle makes it easier to become overweight and increases the chance of easier to become overweight and increases the chance of high blood pressure. high blood pressure.

StressStress — This is often mentioned as a risk factor, — This is often mentioned as a risk factor, but stress levels are hard to measure, and responses to but stress levels are hard to measure, and responses to stress vary from person to person. stress vary from person to person.

(Source = AHA)(Source = AHA)


Hypertension Risk Hypertension Risk FactorsFactors

Uncontrollable risk factorsUncontrollable risk factors

Race — Blacks develop high blood pressure more often Race — Blacks develop high blood pressure more often than whites, and it tends to occur earlier and be more than whites, and it tends to occur earlier and be more severe. severe.

Heredity — If your parents or other close blood relatives Heredity — If your parents or other close blood relatives have high blood pressure, you're more likely to develop it. have high blood pressure, you're more likely to develop it.

Age — In general, the older you get, the greater your Age — In general, the older you get, the greater your chance of developing high blood pressure. It occurs most chance of developing high blood pressure. It occurs most often in people over age 35. Men seem to develop it most often in people over age 35. Men seem to develop it most often between age 35 and 55. Women are more likely to often between age 35 and 55. Women are more likely to develop it after menopause. develop it after menopause.

(Source = AHA)(Source = AHA)


Hemodynamic Determinants of Hemodynamic Determinants of Blood Pressure. Etiology of Blood Pressure. Etiology of HypertensionHypertension

Central DeterminantsCentral Determinants– Heart Rate (HR)Heart Rate (HR)– Stroke Volume (SV)Stroke Volume (SV)– Cardiac Output (CO)Cardiac Output (CO)

Peripheral DeterminantPeripheral Determinant– Peripheral Vascular Resistance (PVR)Peripheral Vascular Resistance (PVR)



Central DeterminantsCentral Determinants– Heart Rate (HR)Heart Rate (HR)

↑ ↑ HR = ↑ BP; ↓HR = ↓ BPHR = ↑ BP; ↓HR = ↓ BP Factors that ↑ HR = Increased metabolism Factors that ↑ HR = Increased metabolism (CO(CO22 levels levels

monitored by brainstem in cerebrospinal fluid),monitored by brainstem in cerebrospinal fluid), Stress Stress (Sympathetic)(Sympathetic) Response Response (↑ epinephrine, norepinephrine),(↑ epinephrine, norepinephrine), ↑ blood volume, ↑ blood volume, ↑ venous return to the heart = ↑ venous return to the heart = (normal exercise response)(normal exercise response)



Central DeterminantsCentral Determinants– Stroke Volume (SV)Stroke Volume (SV)

↑ ↑ SV = ↑ BP; ↓SV = ↓ BPSV = ↑ BP; ↓SV = ↓ BP Factors that ↑ SV = ↑ venous return to the heart = Factors that ↑ SV = ↑ venous return to the heart =

(normal exercise response, “Frank Starling Effect” ), (normal exercise response, “Frank Starling Effect” ), ↑ contractility ↑ contractility (↑ epinephrine, norepinephrine, also increase with exercise as a (↑ epinephrine, norepinephrine, also increase with exercise as a

sympathetic response),sympathetic response),

Note – Systolic blood pressure increases during Note – Systolic blood pressure increases during exercise because of an increased HR and SV.exercise because of an increased HR and SV.



Central DeterminantsCentral Determinants– Cardiac Output (CO)Cardiac Output (CO)

CO = HR X SVCO = HR X SV Anything that ↑ HR and/or SV will ↑COAnything that ↑ HR and/or SV will ↑CO HR measured in beats per minuteHR measured in beats per minute SV measured in milliliters per beatSV measured in milliliters per beat CO in measured in Liters per minuteCO in measured in Liters per minute CO = blood flowCO = blood flow



Peripheral DeterminantPeripheral Determinant– Peripheral Vascular Resistance (PVR)Peripheral Vascular Resistance (PVR)– Is the resistance of the vasculature Is the resistance of the vasculature

against the pumping force generated by against the pumping force generated by the heartthe heart

– Is resistance to flowIs resistance to flow– Is primarily generated by the diameter of Is primarily generated by the diameter of

the artery lumen the artery lumen (space where blood flows through the (space where blood flows through the artery)artery)



Peripheral DeterminantPeripheral Determinant– The smaller the diameter of the artery, The smaller the diameter of the artery,

the greater the resistance to flow.the greater the resistance to flow.– Thus, PVR is mostly generated by the Thus, PVR is mostly generated by the

degree of vasoconstriction.degree of vasoconstriction.– Vasoconstriction is caused by: Vasoconstriction is caused by: ↑sympathetic ↑sympathetic

drive drive (contraction of the smooth muscle cells in the arterial wall).(contraction of the smooth muscle cells in the arterial wall). This is a normal exercise response, that is This is a normal exercise response, that is countered by local vasodilatation from aerobic countered by local vasodilatation from aerobic metabolites. It is not a normal resting response.metabolites. It is not a normal resting response.


Autonomic Nervous SystemAutonomic Nervous System

Increased sympathetic drive – Increased sympathetic drive – increasing levels of epinephrine and increasing levels of epinephrine and norepinephrinenorepinephrine

Effects of epinephrine and Effects of epinephrine and norepinephrine on heart rate and norepinephrine on heart rate and smooth muscle cells in arteries smooth muscle cells in arteries – Increase HR, SV, CO and PVRIncrease HR, SV, CO and PVR


Physical Activity and Reduced Physical Activity and Reduced Hypertension Risk: The Hypertension Risk: The

EvidenceEvidenceCross Sectional StudiesCross Sectional Studies North CarolinaNorth Carolina

– African American AdultsAfrican American Adults– Odds ratio was 1.3x for inactive women Odds ratio was 1.3x for inactive women

compared to active womencompared to active women– After adjusting for other factors, odds After adjusting for other factors, odds

ration was 1.6xration was 1.6x



EvidenceEvidenceCross Sectional StudiesCross Sectional Studies Southern CaliforniaSouthern California

– Caucasian WomenCaucasian Women– Age adjusted systolic and diastolic blood Age adjusted systolic and diastolic blood

pressure in inactive women were 13 mmHg pressure in inactive women were 13 mmHg systolic and 6 mmHg diastolic higher.systolic and 6 mmHg diastolic higher.

– After adjusting for other factors, there was After adjusting for other factors, there was an overall linear trend for lower blood an overall linear trend for lower blood pressure with higher levels of physical pressure with higher levels of physical activityactivity



EvidenceEvidenceCross Sectional StudiesCross Sectional Studies Seventh Day AdventistsSeventh Day Adventists

– African American subjectsAfrican American subjects– Age/Sex adjusted systolic and diastolic Age/Sex adjusted systolic and diastolic

blood pressure in inactive subjects were blood pressure in inactive subjects were 10 mmHg systolic and 4 mmHg diastolic 10 mmHg systolic and 4 mmHg diastolic higher.higher.

– 42% of non-exercisers compared to 20% 42% of non-exercisers compared to 20% of exercisers were diagnosed as of exercisers were diagnosed as hypertensive.hypertensive.



EvidenceEvidenceCross Sectional StudiesCross Sectional Studies Active Commuting in FinlandActive Commuting in FinlandFour independent cross-sectional surveys of Four independent cross-sectional surveys of

random national samples in Finland were random national samples in Finland were carried out at five-year intervals from 1982 to carried out at five-year intervals from 1982 to 1997 as part of the Finnish cohort of the WHO 1997 as part of the Finnish cohort of the WHO MONICA study. Stratified by sex and 10-year MONICA study. Stratified by sex and 10-year age categories, high leisure-time physical age categories, high leisure-time physical activity but not activity for commuting was activity but not activity for commuting was associated with lower DBP among both men associated with lower DBP among both men and women.and women.



EvidenceEvidenceCross Sectional StudiesCross Sectional Studies Active Commuting in CARDIAActive Commuting in CARDIAAssociations were examined between walking or Associations were examined between walking or

biking to work (self-reported time, distance, and biking to work (self-reported time, distance, and mode of commuting) with cardiorespiratory mode of commuting) with cardiorespiratory fitness, leisure-time physical activityfitness, leisure-time physical activity

Men with any active commuting, compared to none, Men with any active commuting, compared to none, had a 50% reduction in odds of having a BMI ≥30 had a 50% reduction in odds of having a BMI ≥30 and had a DBP that was nearly 2 mmHg lower and had a DBP that was nearly 2 mmHg lower than in people who did not walk or bicycle to workthan in people who did not walk or bicycle to work



EvidenceEvidenceProspective Cohort StudiesProspective Cohort Studies Aerobics Center Longitudinal StudyAerobics Center Longitudinal Study

– Relative risk for developing hypertension Relative risk for developing hypertension was 1.5 for the lowest fitness groupwas 1.5 for the lowest fitness group

– The lowest fitness group who had normal The lowest fitness group who had normal systolic and diastolic pressures had 10x systolic and diastolic pressures had 10x the risk of developing hypertension than the risk of developing hypertension than those that were highly fit and had normal those that were highly fit and had normal blood pressures.blood pressures.



EvidenceEvidenceProspective Cohort StudiesProspective Cohort Studies Aerobics Center Longitudinal StudyAerobics Center Longitudinal Study

– People who moved from the lowest People who moved from the lowest fitness group to the highest fitness fitness group to the highest fitness group had about ½ the risk of group had about ½ the risk of developing hypertension of those who developing hypertension of those who remained in the low fitness groupremained in the low fitness group



EvidenceEvidenceProspective Cohort StudiesProspective Cohort Studies Harvard Alumni Health StudyHarvard Alumni Health Study

– Those who expended less than 2000 Those who expended less than 2000 kcal/wk had a 30% greater risk of kcal/wk had a 30% greater risk of developing hypertension than those who developing hypertension than those who expended more than 2000 kcal / wkexpended more than 2000 kcal / wk

– There was an inverse relationship There was an inverse relationship between participation in vigorous between participation in vigorous recreational sports in middle age and recreational sports in middle age and the risk of developing hypertension.the risk of developing hypertension.



EvidenceEvidenceProspective Cohort StudiesProspective Cohort Studies University of Pennsylvania Alumni University of Pennsylvania Alumni

StudyStudy– Those who spent less than 5 hours per Those who spent less than 5 hours per

week in sports participation had a 30% week in sports participation had a 30% greater risk of developing hypertension.greater risk of developing hypertension.

– Participation in vigorous recreational Participation in vigorous recreational sports activity in middle age reduced sports activity in middle age reduced the rate of hypertensionthe rate of hypertension



EvidenceEvidenceProspective Cohort StudiesProspective Cohort Studies Iowa Women StudyIowa Women Study

– The relative risk of developing The relative risk of developing hypertension was 30% higher in women hypertension was 30% higher in women in the lowest active group compared to in the lowest active group compared to the most active groupthe most active group



EvidenceEvidenceProspective Cohort StudiesProspective Cohort Studies The Northwestern Trial The Northwestern Trial

– The incidence of hypertension in the The incidence of hypertension in the control group (Sedentary) was 2x that of control group (Sedentary) was 2x that of the intervention group. the intervention group.

– Other intervention behaviors were not Other intervention behaviors were not controlled, so the independent effect of controlled, so the independent effect of exercise could not be measured. exercise could not be measured.

– Study showed the effectiveness of non-Study showed the effectiveness of non-pharmacological intervention.pharmacological intervention.



EvidenceEvidenceProspective Cohort Studies – Youth StudiesProspective Cohort Studies – Youth Studies New York CityNew York CityA cohort of nearly 200 mainly Hispanic 5-year-A cohort of nearly 200 mainly Hispanic 5-year-

olds who regularly visited an inner-city medical olds who regularly visited an inner-city medical center was followed for 20 months . Age-center was followed for 20 months . Age-related increases in blood pressure were related increases in blood pressure were inversely related to higher fitness. Children in inversely related to higher fitness. Children in the top 20% of fitness gains had a significantly the top 20% of fitness gains had a significantly smaller increase in SBP (3 mmHg per year) smaller increase in SBP (3 mmHg per year) compared to children in the lowest 20% of compared to children in the lowest 20% of fitness gains (5 mmHg per year).fitness gains (5 mmHg per year).



EvidenceEvidenceProspective Cohort Studies – Youth Prospective Cohort Studies – Youth

StudiesStudies The Northern Ireland Young Hearts The Northern Ireland Young Hearts

ProjectProjectCardiovascular risk factors were assessed in a Cardiovascular risk factors were assessed in a random cohort of 229 boys and 230 girls when random cohort of 229 boys and 230 girls when they were 12 years old and again when they they were 12 years old and again when they were age 15. There was a significant relation were age 15. There was a significant relation between self-reports of physical activity and between self-reports of physical activity and lower SBP over the three-year period among boys lower SBP over the three-year period among boys but not girls but not girls


Physical Activity and Physical Activity and Treatment of Hypertension : Treatment of Hypertension :

The EvidenceThe EvidenceStrength of the EvidenceStrength of the Evidence Summary:Summary:

– Regular exercise decreases blood pressure; Regular exercise decreases blood pressure; (SBP -11 mmHg ), (DBP -8 mmHg)(SBP -11 mmHg ), (DBP -8 mmHg)

– People with mild hypertension benefited People with mild hypertension benefited more than those with more severe more than those with more severe hypertensionhypertension

– Women had larger reductions than men Women had larger reductions than men (W=SBP -19; DBP -7 ) (M=SBP – 14; -5 (W=SBP -19; DBP -7 ) (M=SBP – 14; -5 mmHg)mmHg)




– Consistent reductions in BP were found in studies that Consistent reductions in BP were found in studies that set exercise intensity below 75% VO2 maxset exercise intensity below 75% VO2 max

– The reductions in DBP were greater the longer the The reductions in DBP were greater the longer the exercise training program lastedexercise training program lasted

– People with mild hypertension benefited more than People with mild hypertension benefited more than those diagnosed with severe hypertension or those with those diagnosed with severe hypertension or those with normal blood pressures.normal blood pressures.

– Subsequent research has shown that men with severe Subsequent research has shown that men with severe hypertension can benefit from exercise intervention, and hypertension can benefit from exercise intervention, and reduce Left Ventricular Hypertrophyreduce Left Ventricular Hypertrophy



– A newer meta-analysis (See Figure 7.8, next slide) A newer meta-analysis (See Figure 7.8, next slide) accumulated results of 72 randomized controlled trials of accumulated results of 72 randomized controlled trials of 3936 participants in 105 study groups who exercised 3936 participants in 105 study groups who exercised mainly by walking, jogging, running, or cycling for at least mainly by walking, jogging, running, or cycling for at least four weeks four weeks

– exercise training reduced systolic and diastolic pressures exercise training reduced systolic and diastolic pressures measured in a clinic by 3 mmHg and 2.4 mmHg, measured in a clinic by 3 mmHg and 2.4 mmHg, respectivelyrespectively

– The reduction of resting blood pressure was more The reduction of resting blood pressure was more pronounced in 30 groups of patients with mainly stage 1 pronounced in 30 groups of patients with mainly stage 1 hypertension (−6.9 mmHg systolic and −4.9 mmHg hypertension (−6.9 mmHg systolic and −4.9 mmHg diastolic) than in normotensive groups (−1.9/−1.6 mmHg) diastolic) than in normotensive groups (−1.9/−1.6 mmHg)


The EvidenceThe Evidence

Figure 7.8

Cumulative results of 72 randomized controlled trials of chronic exercise and hypertension.


The EvidenceThe EvidenceStrength of the EvidenceStrength of the Evidence Summary of additional interventionsSummary of additional interventions

– A meta-analysis of 105 trials of lifestyle interventions A meta-analysis of 105 trials of lifestyle interventions lasting at least eight weeks on nearly 7000 adults with lasting at least eight weeks on nearly 7000 adults with elevated blood pressure found that aerobic exercise elevated blood pressure found that aerobic exercise compared favorably to dietary changes, as shown in compared favorably to dietary changes, as shown in Table Table 7.37.3. The evidence did not support the use of relaxation . The evidence did not support the use of relaxation therapies or calcium, magnesium, or potassium therapies or calcium, magnesium, or potassium supplements to reduce blood pressure supplements to reduce blood pressure


Strength Of The EvidenceStrength Of The Evidence

Temporal SequenceTemporal Sequence– Large cohort studies show lowered risk of Large cohort studies show lowered risk of

developing hypertension following exercisedeveloping hypertension following exercise Strength of the AssociationStrength of the Association

– Collective findings show a 30-50% Collective findings show a 30-50% reduction in risk when active are compared reduction in risk when active are compared to inactiveto inactive

ConsistencyConsistency– Physical activity reduces blood pressure Physical activity reduces blood pressure

regardless of age, sex, or race.regardless of age, sex, or race.



Dose ResponseDose Response– No evidence of an intensity dose No evidence of an intensity dose

response; however, there is an effective response; however, there is an effective intensity rangeintensity range

– This range was 30-85% aerobic capacityThis range was 30-85% aerobic capacity– Duration of exercise 15-60 minutesDuration of exercise 15-60 minutes– Frequency of exercise 3-4x / week, for at Frequency of exercise 3-4x / week, for at

least four weeks.least four weeks.



Biological PlausibilityBiological Plausibility– Possibly a reduction in plasma volume that Possibly a reduction in plasma volume that

decreases resting cardiac outputdecreases resting cardiac output– A reduction in resting catecholamines suggest A reduction in resting catecholamines suggest

that exercise training decreases the sympathetic that exercise training decreases the sympathetic drive lowering blood pressure via decreased HR drive lowering blood pressure via decreased HR and PVRand PVR

– There is a relationship between blood insulin There is a relationship between blood insulin levels and hypertension, thus weight loss can levels and hypertension, thus weight loss can promote a reduction in hypertension by reducing promote a reduction in hypertension by reducing hyperinsulinemiahyperinsulinemia

– There may be a blunted sympathetic response to There may be a blunted sympathetic response to external stressors following exercise interventionexternal stressors following exercise intervention


END OF PRESENTATIONEND OF PRESENTATION

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