PEP 532: Health and Community Development

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PEP 532 Health and Community Development
Heart Disease and Exercise
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How big of a problem is heart disease?

• Heart disease is the leading cause of death for
  both women and men in the United States.
• In 2002, 696,947 people died of heart disease
  (51 of them women).
• This was 29 of all U.S. deaths
• Heart disease is the leading cause of death for
  American Indians and Alaska Natives, African
  Americans, Latinos, and Whites.
• In 2006, heart disease is projected to cost more
  than 258 billion, including health care
  services, medications, and lost productivity.

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Mississippi all residents
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Age-adjusted Average Deaths per 100,000 State
Rate 707 National Rate536
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Mississippi comparison of ethnic groups
The incidence and location of heart disease is
highly variable, depending on ethnicity
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Idaho
Deaths per 100,000 Ages 35, 1996 2000 State
Rate 435 National Rate 536

• Wide distribution of where the death rates are

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Idaho comparison of ethnicity

• There are significant differences in Idaho also

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What are the risk factors (gt20 yrs)?

• Risk factors for heart disease among adults ()
• Hypertension or taking hypertension meds 30.2
• High blood cholesterol 17.3
• Diagnosed diabetes 6.5
• Obesity 30.5
• Smoking 21.6
• No leisure-time physical activity 37.6
• Having two or more of the six risk factors 37

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Does exercise have a protective effect?

• There is a substantial body of literature
  demonstrating that inactivity is an independent
  risk factor for cardiovascular disease and
  overall mortality
• Both low levels of physical activity and obesity
  independently increase the risk
• Mortality can reduced by as much as 50 with
  regular exercise
• There is little doubt that exercise is
  beneficial, but why?

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Cardiac hypertrophy

• There are 2 general types
• Due to genetic mutations
• Reactive hypertrophy type that occurs in
  response to an increase in cardiac work
• Typically a pressure-load
• Overall, there are two different categories
• Physiological hypertrophy what you see after
  exercise training
• Pathological hypertrophy due to sustained
  hypertension or aortic stenosis
• The difference being that the latter ultimately
  leads to heart failure

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Cardiac hypertrophy

• These changes (for the better or worse) can be
  seen as altered cardiac geometry (size and
  shape) referred to as ventricular remodeling

Dorn II, G.W. The Fuzzy Logic of Physiological
Cardiac Hypertrophy. Hypertension. 200749962-970
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Does exercise have a protective effect?

• The caveat is that sudden death occurs
  disproportionally with vigorous exercise
• However the majority of sudden death occurs in
  two general categories
• Young individuals that have hereditary or
  congenital abnormalities (1/133,000 men and
  1/769,000 women)
• Older individuals in many cases there was a
  previous diagnosis of heart disease
• Overall, there is an increased risk of death, but
  an overall reduction in heart disease

Thompson, PD. Exercise and Acute Cardiovascular
Events Placing the Risks Into Perspective A
Scientific Statement From the American Heart
Association Council on Nutrition, Physical
Activity, and Metabolism and the Council on
Clinical Cardiology. Circulation.
20071152358-2368.
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Reasons for sudden death

• Thompson, PD. Exercise and Acute Cardiovascular
  Events Placing the Risks Into Perspective A
  Scientific Statement From the American Heart
  Association Council on Nutrition, Physical
  Activity, and Metabolism and the Council on
  Clinical Cardiology. Circulation.
  20071152358-2368.

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Risk of heart attack vs. habitual vigorous
exertion

• Overall, a reduced risk if habitual

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What does exercise do?

• Up until the 1990s, it was thought that people
  with heart disease of after a heart attack should
  restrict their activity
• Bed rest improved the symptoms
• By 2005, American Heart Association recommended
  exercise training for all stable out-patients

Subodh B. Joshi, Exercise Training in the
Management of Cardiac Failure and Ischaemic Heart
Disease. Heart, Lung and Circulation
200716S83S87
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Rates of death during cardiac rehab

• Luckily the rates are typically very low

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Exercise as treatment with heart disease?

• There is little doubt that exercise training in
  those with a failing heart significantly improve
  functional capacity
• Significant increases in
• Endothelial function
• Coronary blood flow
• Blood flow and O2 extraction in active muscles
• The big question is whether heart function is
  actually improved to the extent observed in
  normal hearts
• Perhaps because those with failing hearts cannot
  exercise hard enough?

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What about resistance training?

• Seems counterintuitive to provide an exercise
  mode that further increases vascular resistance
  and pathological hypertrophy?
• But, muscle strength has been shown to be a
  better predictor of long-term survival than
  VO2max!
• Recommendations are to not lift strenuously, like
  weight-lifting athletes
• Lower weight, and not to exhaustion
• Subjects were generally monitored quite closely

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Types of RT

• Rate pressure product (RPP) HR x SBP (measure of
  myocardial O2 consumption)
• RT was lower than a stress test

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What is hypertension?

• According to the CDC 1 of 3 American adults has
  high blood pressure
• High blood pressure increases the chance of
  developing heart disease, a stroke, and other
  serious conditions.

http//www.cdc.gov/bloodpressure/
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How big of a problem is it?

• Hypertension was listed as a primary or
  contributing cause of death for 277,000 Americans
  in 2002
• Almost one third of the people with high blood
  pressure don't know that they have it.
• It is estimated that about 90 of middleaged
  adults will develop high blood pressure in the
  remainder of their lifetime

Ageadjusted Percent of Adults Aged 20 Years and
Older With Hypertension or Taking Blood
PressureLowering Medication, 19992002
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Types of hypertension

• Essential hypertension
• high blood pressure does not have a specific
  treatable cause (most cases).
• Secondary hypertension
• Hypertension is the result of some other
  underlying condition
• This may be due to kidney disorders, congenital
  abnormalities, or other conditions.
• Pregnancyrelated hypertension
• Existing high blood pressure can predispose some
  women to develop problems when they become
  pregnant.

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Why is it a problem?

• It can lead to hardened or stiffened arteries,
  which causes a decrease of blood flow to the
  heart muscle and other parts of the body.
• Increase risk of angina
• Heart attack (chronic spasm or blockage of blood)
• Major structural adaptation is left ventricular
  hypertrophy
• Tend to see "concentric remodeling"
• ? LV wall thickness/ LV chamber dimension

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Why is it a problem?

• A major risk factor for stroke
• Damage to the eyes, including blindness.
• Kidney disease and kidney failure.
• High BP can thicken and narrow the blood vessels
  of the kidneys, resulting in less fluid being
  filtered and wastes building up in the body.
• Also, diseases of the kidney can be a cause of
  high blood pressure.

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Treatment of hypertension

• First step is to implement lifestyle
  modifications, and if needed, with medications.
• Weight control, exercise, healthy diet, limiting
  alcohol use
• Medications such as
• Diuretics reduce water and sodium retention
• Betablockers reduces heart rate
• Angiotensinconverting enzyme (ACE) inhibiters
  prevent the formation of a angiotensin II, which
  normally causes the blood vessels to narrow.
• Vasodilators open the blood vessels by relaxing
  the muscle in the vessel walls.

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Does exercise have an effect?

• Several cross-sectional and longitudinal studies
  have demonstrated an inverse relationship between
  physical activity and hypertension
• Both acute and chronic exercise results in a
  reduction of 5-7 mmHg (systolic)
• Reductions as small as 2 mmHg are sufficient to
  reduce the risk of stroke and coronary artery
  disease
• Moderate intensity exercise is the most
  recommended (?30 min/day)
• With the assumption that the patient has been
  given approval by a physician
• ACSM Position Stand, 2004
  

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Lifestyle modifications

• Exercise is a part, but diet is another
• ? alcohol, sodium, and calcium intakes
• DASH diet (Dietary Approaches to Stop
  Hypertension)
• ? fat and sodium, ? high fruits and vegetables
• Drug therapy is effective and can be combined
  with exercise, but
• Can be inconvenient and expensive
• Adverse side-effects

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Other beneficial effects?

• Weight loss can independently reduce BP
• Loss of 8- 9 Kg is associated with a ? 6-10 mmHg
  (systolic) and 3-7 mmHg (diastolic)
• Therefore, if you can reduce body weight through
  exercise, there could be additional benefits
• More on this later

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Summary of different effects

• Exercise plays a role, but not the best effects
  when not combined with other interventions

Bacon, S.L. Effects of Exercise, Diet and Weight
Loss on High Blood Pressure. Sports Med 2004 34
(5) 307-316
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Summary

• Overall, there is little doubt that regular
  exercise has a cardioprotective effect, and is
  recommended for those that have chronic heart
  failure
• Programs that implement endurance and strength
  training are appropriate
• But other parts like diet counseling , stress
  management, etc are important also
• The effect of exercise on hypertension is less
  pronounced
• From a community design perspective. Why are the
  communities in Idaho (and the country) so
  different from each other in heart disease
  mortality?