EXERCISE

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EXERCISE CARDIOVASCULAR DISEASE
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CHOLESTEROL

• Cholesterol is an important part of a healthy
  body
• It is used for producing cell membranes, some
  hormones, and vitamin D.

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CHOLESTEROL

• You get cholesterol in two ways.
• Your body makes some of it, and the rest comes
  from cholesterol in animal products that you eat,
  such as meats, poultry, fish, eggs, butter,
  cheese and whole milk.
• Food from plants like fruits, vegetables and
  cereals doesn't have cholesterol.
• Some foods that don't contain animal products may
  contain trans-fats, which cause your body to make
  more cholesterol.
• Foods with saturated fats also cause the body to
  make more cholesterol.

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CHOLESTEROL

• Cholesterol and other fats can't dissolve in the
  blood. They have to be transported to and from
  the cells by special carriers called
  lipoproteins.
• There are two kinds that you need to know about.
  Low-density lipoprotein, or LDL, is known as the
  "bad" cholesterol.
• Too much LDL cholesterol can clog your
  arteries, increasing your risk of heart attack
  and stroke.
• High-density lipoprotein, or HDL, is known as the
  "good" cholesterol. Your body makes HDL
  cholesterol for your protection. It carries
  cholesterol away from your arteries.
• Studies suggest that high levels of HDL
  cholesterol reduce your risk of heart attack.

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How is cholesterol involved with atherosclerosis?

• Injury HTN, inflammation, infection, trauma,
  toxic materials, etc.
• Fatty streak monocytes form foam cells which
  become fatty streaks and plaques
• Migration and aggregation macrophages secret
  growth factors for smooth muscle cells, produce
  reactive oxygen materials which cause LDL to
  accumulate
• Lipid accumulation
• Maturation of the lesion

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CHOLESTEROL MISCONCEPTIONS

• Using margarine instead of butter will help lower
  my cholesterol.
• Thin people dont have to worry about high
  cholesterol.
• Since the nutrition label on my favorite food
  says theres no cholesterol, I can be sure that
  its a heart-healthy choice.
• I recently read that eggs arent so bad for your
  cholesterol after all, so I guess I can go back
  to having my two eggs for breakfast every
  morning.

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Physical activity and cardiovascular disease
evidence for a dose response

• KOHL, HAROLD W. III. Medicine and Science in
  Sports and Exercise Volume 33(6) Supplement June
  2001 pp S472-S483

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CARDIOVASCULAR DISEASE

• The major observational studies relating the risk
  of CVD incidence and mortality to physical
  activity indicate that the relation is likely
  causal, and the majority provide convincing
  evidence for a dose-response relation.
• A limitation of these studies, however, is that
  CVD is a large collection of diseases and
  disorders, many which may not be related to the
  atherosclerotic process or other biologic
  mechanisms that may be affected by physical
  activity

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CORONARY HEART DISEASE

• 31 publications relating dose of physical
  activity to risk of CHD have been published since
  1958
• Twenty of the reviewed studies were judged to
  provide support for a dose-response relation
  between physical activity and CHD
• Three studies provided mixed support for such a
  relation depending on the indices of physical
  activity used or cohort characteristics (data
  stratification) presented.
• Eight studies did not support the conclusion of a
  dose-response relation between physical activity
  and CHD
• Physical activity is inversely related to risk of
  CHD, and the bulk of the observational studies
  suggest this inverse relation to be a dose
  response.

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STROKE

• Fifteen major studies (16 separate publications)
  that provide evidence toward evaluation of a
  physical activity dose-stroke response are
  available for review.
• Six of the studies were judged to provide
  evidence of a dose-response relation
• Eight studies provided no support for a
  dose-response relation
• Two provided mixed support (varying results in
  separate subanalyses) Strikingly, several studies
  reported prominent U-shaped distributions of the
  relation between physical activity and risk of
  stroke
• The importance of this observation lies in the
  fact that the pathophysiology of the two types of
  stroke is very different, and it is possible that
  physical activity may be differentially related
  to one type (occlusive) and not the other.

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SUMMARY

• Physical activity is causally and inversely
  related to the risk of death due to CHD.
• A variety of mechanisms are available.
• Physical activity is known to indirectly do so
  and to positively be associated with blood
  pressure, clotting factors, glucose tolerance,
  and smoking habits all factors that have been
  associated with increased risk of stroke.

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SUMMARY

• Given the probability of common pathophysiologic
  mechanisms in CHD and ischemic stroke, namely
  atherosclerosis, it follows that physical
  inactivity would also adversely affect the risk
  of stroke.
• Although attractive as a hypothesis, the
  currently available data are equivocal concerning
  the role that physical activity may play in the
  risk of stroke.
• Existing studies do not show the consistencies
  noted in the association that are seen for CVD
  and CHD and do not support the conclusion of a
  dose-response relation.

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Response of blood lipids to exercise training
alone or combined with dietary intervention

• Medicine and Science in Sports and Exercise
  Volume 33(6) Supplement June 2001 pp S502-S515
• LEON, ARTHUR S. SANCHEZ, OTTO A.

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The National Cholesterol Education Program (NCEP)

• Total cholesterol (TC) level of 6.2 mmolL- 1
  (gt240 mgdL- 1)
• LDL-C level of 4.1 mmolL- 1 (gt160 mgdL- 1)
• TC levels of 5.2 mmolL- 1 to 4.0 mmolL-1
  (200-239 mgdL- 1)
• LDL-C levels of 34 mmolL- 1 (130 mgdL- 1) as
  borderline high.
• In the presence of CVD or two or more other risk
  factors, borderline levels of TC and LDL-C are
  considered elevated.
• HDL-C levels 0.9 mmolL- 1 (35 mgdL- 1)
  classified as low
• HDL-C levels 1.6 mmolL-1 (60 mgdL) as a
  negative risk factor or a protective factor
  against CHD

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PHYSICAL ACTIVITY

• A consensus exists that physical inactivity and
  reduced cardiorespiratory endurance contribute to
  risk of CHD
• A consensus already exists that at least 12 wk of
  endurance exercise is required to have a training
  effect on blood lipids
• Particularly an increase in HDL-C and a reduction
  in TG levels

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EXERCISE TRAINING

• 51 studies uncovered in this literature search,
  of which 28 were randomized RCT.
• Exercise training was performed at a moderate to
  hard intensity, three to five times per week for
  30 min or more per session.
• The duration of exercise training ranged from 12
  wk to 2 yr.
• Training generally resulted in significant
  improvements in VO2max ranging from lt3 to over
  50, with the mean increase across studies of
  15.7.

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EXERCISE TRAINING

• The most commonly observed lipid change was a
  significant (P lt 0.05) increase in HDL-C in 24 of
  the 51 studies (47).
• The exercise-induced change in HDL-C ranged from
  a decrease of 5.8 to an increase of about 25,
  with a mean increase of 4.6 across these studies
  (P lt 0.05)
• It has been well documented by feeding
  experiments that a reduced saturated fat intake
  in addition to reducing targeted LDL-C also is
  likely to reduce HDL-C
• It appears from this review that aerobic exercise
  training negates or attenuates this
  dietary-induced reduction in HDL-C, particularly
  if there is an associated substantial weight
  loss, i.e., 4 kg.

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EXERCISE TRAINING

• Exercise training in the absence of simultaneous
  dietary interventions resulted in mean reductions
  in TG, LDL-C, and TC of about 3.7 (P lt 0.05),
  5.0 (P lt 0.05), and 1.0 (P NS), respectively,
  across studies.
• This review confirms the observations of previous
  reviewers of a marked inconsistency in blood
  lipid changes with endurance exercise training
  with an increase in HDL-C noted in only about
  half of the reported studies.

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SUMMARY

• Although there is a great deal of inconsistency
  in the response of blood lipids to endurance
  exercise training in both RCT and non-RCT, the
  bulk of the evidence supports this hypothesis.
• It is estimated that for every 0.026 mmolL-1 (1
  mgdL-1) increase in HDL-C, the risk for a CHD
  event is reduced by 2 in men and at least 3 in
  women.
• The data reviewed here suggest that sex is not a
  predictor of responsiveness of HDL-C to training,
  with adult men and women appearing to respond
  similarly.

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SUMMARY

• Age also does not appear to be a predictor of
  lipid responsiveness to exercise training, with
  elderly men and women as likely, or perhaps even
  more likely, than younger individuals to increase
  HDL-C with training.
• On the basis of this review, baseline lipid
  levels appear to strongly influence the lipid
  response to training.
• A low pre-training HDL-C was shown to be a
  moderately strong predictor of a positive HDL-C
  response to training.

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SUMMARY

• There currently are insufficient data from
  available training studies to conclusively
  establish a dose-response relationship between
  intensity and volume of exercise and lipid
  responses, suggested by observational studies.

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AHA Scientific Statement

• Exercise and Physical Activity in the Prevention
  and Treatment of Atherosclerotic Cardiovascular
  Disease
• Circulation. 20031073109

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EXERCISE AND CAD

• Epidemiological studies, combined with studies
  providing biological plausibility, provide
  conclusive evidence that physical activity
  reduces the incidence of CAD.
• Physical activity both prevents and helps treat
  many established atherosclerotic risk factors,
  including elevated blood pressure, insulin
  resistance and glucose intolerance, elevated
  triglyceride concentrations, low high-density
  lipoprotein cholesterol (HDL-C) concentrations,
  and obesity.
• Exercise in combination with weight reduction can
  decrease low-density lipoprotein cholesterol
  (LDL-C) concentrations and limit the reduction in
  HDL-C that often occurs with a reduction in
  dietary saturated fat.

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EXERCISE AND CAD

• Cardiac mortality was reduced 31 (Plt0.05) and
  26 (Plt0.05) for the exercise-only and
  comprehensive programs, respectively.
• Neither the exercise-only program nor the
  comprehensive intervention significantly reduced
  the rate of nonfatal myocardial infarction.
• Rates of sudden cardiac death were not reduced,
  although only 4 exercise-only and 14
  comprehensive rehabilitation trials analyzed this
  outcome.
• Only 5 exercise-only trials and 10 comprehensive
  trials examined the rate of coronary artery
  bypass grafting.

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EXERCISE AND CAD

• Exercise-based cardiac rehabilitation reduces
  cardiac mortality (27) but does not reduce the
  risk of recurrent myocardial infarction.
• Exercise is useful for patients with angina
• Exercise may improve electrical stability and
  coronary vasomotor responses.

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EXERCISE AND CAD

• The most common risk of physical activity is
  musculoskeletal injury
• Increase risk due to obesity, volume of exercise,
  and vigorous exercise
• Vigorous exercise (gt 60) increases the risk of
  sudden cardiac death and MI
• The incidence of sudden death is not well defined
• Approximately 5-10 of MI are associated with
  vigorous exercise

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SUMMARY

• 1. Physical activity and exercise training have
  important roles in
• A. Preventing atherosclerotic CAD
• B. Managing selected CAD risk factors, including
  elevated triglyceride levels, low HDL-C,
  hypertension, glucose intolerance, hypertension,
  obesity, and possibly cigarette use
• C. Treating patients with CAD, HF, and
  claudication.

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SUMMARY

• 2. Healthcare professionals should
• A. Engage in an active lifestyle
• B. Encourage schools to teach skills required for
  physically active lifestyles and communities to
  develop programs and facilities conducive to
  physical activity
• C. Be educated about exercise as a therapeutic
  modality and the importance of lifelong physical
  activity in their patients
• D. Routinely prescribe exercise and increased
  physical activity to their patients in accordance
  with recommendations provided by the CDC/ACSM7
  and the AHA
• E. Perform exercise testing before vigorous
  exercise in selected patients with cardiovascular
  disease and other patients with symptoms or those
  at high risk.

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SUMMARY

• 3. Additional research should
• A. Address behavioral strategies to increase and
  maintain physical activity over the lifespan
• B. Increase the scientific rationale supporting
  the importance of physical activity by examining
  the amount of exercise required to alter CAD
  risk, the effect of exercise on morbidity and
  mortality, and its cost-effectiveness.