Aging, Exercise, and Cardiovascular Health
Chapter 20
Exercise and Health
o o Exercise and Aging Exercise and disease prevention
CHD Diabetes Cancer Stroke
Exercise and Aging
o o o o 7-8% of adults: regular vigorous exercise 32-36% of adults: Regular low intensity exercise (lower than recommended) Exercise incidence typically w/ age * More than half of individuals who begin regular exercise program quit within first 6 months
• Centers for Disease Control
Exercise and Aging
o Functional capacity peaks between 20 and 30 years of age and decreases with advancing years. Active people show 25% higher functional capacity at any age over sedentary counterparts! Physical capacity will decline w/ age, but older people can still improve!
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Exercise and Aging
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Muscular Strength
Peaks between 20 & 30 and declines approximately 30% by age 70
Due to reduced muscle mass (likely an actual loss of fibers)
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Muscles are still trainable
ST decreases muscle protein loss Gains in strength (%) in elderly are similar to those seen in the young Increases and maintains flexibility
Exercise and Aging
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Nervous System
37% decline in spinal cord axons 10% decline in conduction velocity Loss of elasticity of connective tissue
Decreased RT and muscle contraction velocity Minimized by exercise
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Pulmonary Function
Older, endurance trained individuals score significantly higher on PFT’s
Exercise and Aging
o Cardiovascular Function
Aerobic capacity decreases 35% by age 65 Hrmax declines with age (220-age) SV decreases* Reduction of blood flow due to stenosis (Heart?) Decreased elasticity of major vessels
Exercise and Aging
o Cardiovascular System Responds to Training at any AGE!!!
Adaptations (%) similar to those seen in younger individuals. Decline may be 2X’s faster however.
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Body Composition
Exercise diminishes increase in BF% seen with aging
Aging vs. Sedentary Lifestyle
o Aging and being sedentary combined, facilitates loss of physical capacity. Many people blame “getting old” for everything (usually lack of activity). Human body improves with activity...REGARDLESS OF AGE!!!
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Exercise to Improve Health and Extend Life
o Harvard Alumni Study (Classes of 1920 - 1954)
Exercise improved health and reduced mortality Hypertensives: Reduced death rate by 50% Individuals with parents who died prior to age 65: Reduced death rate by 25%
Harvard Alumni Study
% Death Risk Reduction
60 50 40 30 20 10 0 5 5 to 10 10 to 15 15 to 20 20 to 25 25 to 30 30 to 35
Miles Walked / Run per Week
Exercise to Improve Health and Extend Life
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Epidemiological evidence
Studies have shown a cause - effect relationship between physical inactivity and CHD (sedentary person = 2X’s risk) Protective association just as strong as hypertension, smoking, and high cholesterol. Physical inactivity is the GREATEST risk factor for heart disease...more people are physically inactive than possess ALL other CHD risk factors!
Light Activity is Valuable
70
Deaths / 10,000
60 50 40 30 20 10 0 1
Low
2 3 Fi tnes s Lev el
4
5
High
Cardiovascular Diseases
Cardiovascular diseases including: Coronary Artery Disease (CAD) or Coronary Heart Disease (CHD), are the leading killer of Americans.
Cardiovascular disease includes all diseases associated with the heart and / or blood vessels.
Cardiovascular Diseases
o Cardiovascular diseases can lead to myocardial infarction (heart attack), stroke, embolisms, aneurysms, etc. Incidence of deaths from heart disease have declined since 1970 (due to advances in technology, not decrease in CHD incidence) Annual costs over 120 billion dollars!
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Cause of Death in the USA
Other 18% COPD 3% Pneumonia 3% Accidents 5% CVD 50%
Cancer 21%
Coronary Artery Disease (CAD)
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Coronary circulation
ALL blood supplied to heart is done so via two coronary arteries (Right & Left) that bifurcate from the aorta just above the LV. There is absolutely NO blood perfusion from inside the chambers of the heart. If coronary artery is blocked, the heart may be starving for O2 all the while it is full of oxygenated blood.
1.) Right Coronary artery
2.) Left Coronary Artery
Coronary Artery Disease (CAD)
o Degenerative changes involving the lining of major vessels supplying blood to the heart. Various compounds interact with these changes (injured areas) including the oxidative reaction of LDL-C to form a “fatty streak”. This is the first sign of atherosclerosis. Eventually a plaque is formed and the body will respond by generating scar tissue.
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Coronary Artery Disease (CAD)
o o All of these lead to a narrowing of the CA. Eventually causes the myocardium (heart muscle) to become ischemic, or poorly supplied with oxygen…Often associated with angina or chest pains. Blood flow may become very slow and turbulent causing development of a clot or thrombus.
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Myocardial Infarction
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Myocardial Infarction:
The result of inadequate perfusion of blood in the coronary arteries. Caused by a significant reduction in the diameter of the vessel (most often caused by a thrombus). Many people suffer MI’s without ANY prior symptoms! Mortality rate decreases in individuals who are exercise trained.
Symptoms Suggestive of CAD
Pain or discomfort in chest, jaw, or arm* Shortness of breath* Dizziness* Orthopnea (diff. Breathing when supine) Ankle edema (chronic) Claudication* Unusual fatigue or dyspnea with light activity
*Usually,but not always experienced during exertion
CAD Begins Early
o Fatty streaks are common in children as young as 5 yrs. Studies examining autopsy results of Vietnam casualties (avg. age 19 yrs.) showed significant CAD in majority of men.
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Risk Factors for CAD
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Modifiable
Obesity Sedentary life Blood lipids Diet Hypertension Smoking Diabetes Tension & stress Education
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Non-Modifiable
GENETICS *
• • • Family History* Race Sex
Age
Modifiable Risk Factors
Minimizing modifiable risk factors is our best defense against developing CAD! It is impossible to weight various risk factors, because of the role of genetics. Some people simply don’t develop heart disease because of the presence of a certain risk factor, when some one else may.
Modifiable Risk Factors
o Primary Risk Factors
Lipid levels (cholesterol) Blood pressure Smoking Physical Inactivity
Modifiable Risk Factors
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Blood lipid abnormalities
Actual mechanism is not yet fully understood
However, strong statistical link with TC, LDL-C, & HDL-C and incidence of CAD. TC < 200 mg/dL LDL-C < 130 mg/dL HDL-C > 35 mg/dL TG < 135 mg/dL (males) 160 mg/dL (females)
Modifiable Risk Factors
o o o LDL-C transports cholesterol from the liver to the cells of the body (arteries) HDL-C removes cholesterol from body cells and transports it to the liver for excretion as bile. TC / HDL-C ratio is the best indicator of a favorable lipid profile (<4.5)
Modifying Blood Lipid Levels
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Favorable Effects
Weight loss Exercise High water-soluble fiber intake High polyunsat. – saturated fat ratio Intake of omega-3 fatty acids (fish) Moderate alcohol consumption
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Unfavorable Effects
Smoking Diet high in saturated fat and cholesterol Stress Oral contraceptives Sedentary lifestyle
Modifying Blood Lipid Levels
o Blood lipids are still very dependant on a person’s genetic makeup! Some people respond to diet and exercise, some require medication. Lowering elevated lipids is extremely important for minimizing CAD risk!
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Hypertension
o Elevated blood pressure may be caused by several things; HTN is result of either:
Excessive vasoconstrictor tone*
• Arteriosclerosis: hardening of arteries
High blood volume
Hypertension
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High blood pressure is defined as resting systolic > 140 mm/Hg and/or diastolic > 90 mm/Hg. Incidence increases with:
Family history High Na+ intake Stress Obesity Kidney ailments Smoking
Hypertension
o Often called “silent killer”
Most people do not know they have it 90% of causes are of unknown etiology (essential hypertension) Uncorrected, HT can lead to heart failure, heart attack, stroke, and kidney failure. Exercise is often the best way lower borderline – hypertension.
Smoking
o o Increases CAD risk 2X & stroke risk 5X. Smoking has negative effect on blood lipids and increases incidence of hypertension. Each cigarette smoked equates to a loss of seven minutes of life – Americans loose 5 million years of potential life annually to smoking!
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Physical Inactivity
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Exercise protects against CAD by:
Normalizing blood lipid profile (increased HDL-C and lowered LDL-C) Lowered blood pressure and HRrest (less physical demand / work on myocardium) Improving myocardial circulation and metabolism (protects heart during hypoxic stress)
• • Increased vascularization Increased glycogen stores and anaerobic capacity
Physical Inactivity
o Exercise protects against CAD by:
Increased myocardial contractility & vascularization Developing a more favorable body composition Decreases clot formation Reduces stress and tension
Obesity
o Determining importance of obesity as a risk factor is difficult since it is almost always seen in conjunction with other risk factors. Overweight (>30% BF) see a 70% increased mortality risk. Increased risk of CAD, diabetes, and stroke.
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Diabetes
o High blood glucose levels increase degeneration seen in vessels. Diabetics often have circulatory problems throughout the body. High blood sugar levels will irritate plaques in CA and increase likely hood of them enlarging and/or developing clots
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Diabetes and Exercise
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Most diabetics are Type II, adult onset. Exercise and obesity are the two largest risk factors for Type II diabetes.
Most often caused by insulin receptor insensitivity (brought on by huge fluctuations in blood sugar)
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Most Type II diabetics can control blood glucose with diet and exercise and can often live completely free of insulin therapy.
Stress, Tension, & Type A’s
o Increased incidence of CAD is seen in individuals with high levels of stress, self reported tension, or who are classified as “Type A” personalities. RELAX!
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Non-modifiable Risk Factors
o Family History: Likely the most POTENT risk factor! Age: Incidence increases with age. Sex: Females have less CAD at any given age than male counterparts. (Protective mechanisms of estrogen) Race: Different races show different CAD rates (Genetics, diet, and lifestyle)
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Risk Factors (Summary)
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Age: Males > 45 yrs , Females > 50 yrs Sex: Males > Females Family History: exponentially worse if both parents have positive history Lipids:
TC<200 HDL-C > 35 TG<135 – 160 LDL-C < 130
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Blood Pressure: < 140 / 90 mm/Hg
Risk Factors (Summary)
o o o o o o Physical Inactivity Diet high in fat and cholesterol Smoking High BF% (Obesity) Diabetes Stress and tension
Interaction of Risk Factors
CAD Incidence / 100,000
600 500 400 300 200 100 0 None One Two Three
CAD Risk Factors