quiz #3 Flashcards
coronary heart disease
coronary heart disease
also known as “ischemia” heart disease, ischemia= lack of blood flow
- a condition characterized by the narrowing or blockage of the coronary arteries due to the buildup of plaque
can result in: angina, shortness of breath, fatigue with exercise, myocardial infarction ( heart attack)
atherosclerosis
process that leads to CHD
- buildup of plaque within the walls of arteries
- plaque= fatty deposits, low-density lipoproteins, inflammation, hemostasis
happens in coronary arteries
what regions in the US have the highest prevalence rates?
southeast regions
where does CHD rank compared to other top causes of death in the US?
Globally?
number 1
modifiable risk factors for CHD
hypertension, sedentary lifestyle, diabetes, obesity, dyslipidemia (elevated lipids)
non-modifiable risk factors for CHD
genetics, males, old age, and smoking
relationship with pa
having a sedentary lifestyle leads to hypertension, dyslipidemia, which increases chance for coronary heart disease
being physically active allows for normal bp, stable cholesterol and a reduced risk for CHD
findings London bus study
1.) risk of coronary heart disease: bus conductors < bus drivers, total incidence
- first appearance of coronary heart disease may occur at a younger age in drivers
- generally bus conductors had a lower risk of developing coronary heart disease than bus drivers
2.) role of other risk factors
Hypertension: bus conductors < bus drivers, overall, bus conductors had lower bp
- among those w/ similar bp, risk of CHD was lower in bus conductors
Obesity: overall, bus conductors had less incidence of obesity
- among those w/ similar BMI, rate of death due to CHD was higher in bus drivers
London bus study, occupational physical activity
1.) active jobs reduce the rate and severity of coronary heart disease (CHD)
2.) CHD may occur at earlier ages for individuals with sedentary jobs
3.) occupational PA may have an independent role in reducing risk when considering other factors such as blood pressure and obesity
findings Harvard alumni health
- Age-adjusted incidence rate of CHD inversely
related to energy expended on physical
activities. - Men expending fewer than 2000 kcal per week
had a 64% higher risk than more active
classmates. - CHD risk (i.e., first heart attack) decreased by
about 10% more when energy expenditure
occurred in vigorous sports compared to
walking or climbing stairs.
harvard alumni adjustments for confounding
hypertension, smoking, diabetes, obesity
harvard: previous athletic activity
- Former College Athletes who were
no longer active - Alumni who were not college
athletes and were after graduation
Does previous athletic participation
have a protective effect on risk of - Alumni who were athletes during college
but did not continue exercising were at
greater risk for CHD than physically active
alumni who hadn’t been college athletes
Leisure physical activity
- Greater energy expenditure (i.e., greater
volume) of LTPA reduces the risk of
developing CHD - Previous athletic participation does not have
a protective effect
findings for aerobic center longitudinal study
The greatest difference in
mortality rates was between low-
and moderate-fitness categories.
Further reductions were seen
between moderate- and high-
fitness categories.
1. Highly Fit (Top 40%) vs.
Moderately Fit (Middle 40%):
o CVD mortality rate was
half for highly fit men
2. Least Fit (Bottom 20%) vs.
Moderately Fit (Middle 40%):
o CVD mortality rate for least
fit men was 3 X’s greater
Similar trends were noted where
less fit women had higher rates of
CVD mortality than more fit
women.
physical fitness ACLS
- The increased risk of CHD mortality
associated with low fitness was found
to be similar in magnitude to or
stronger than other known CHD risk
factors ==
Dyslipidemia
(Elevated Lipids) Smoking
Hypertension
(High Blood Pressure) Diabetes - This identifies an important risk factor
that is modifiable through physical
activity, which can have a significant
impact on CHD mortality
population attributable risk (PAR)
> Estimate of disease rate reduction if all individuals eliminated a specific risk factor
if all individuals in the studied population
disengaged / engaged in [insert behavior], the
mortality rate from Coronary Heart Disease
(CHD) would be reduced by [insert %]
EX: if all individuals in the studied population had
high cardiorespiratory fitness, the mortality
rate from Coronary Heart Disease (CHD)
would be reduced by 39%
mechanisms that explain rship between chd and physical activity
1.) Anti-inflammatory effects: PA —–> weight loss
2.) Effects on Blood Clotting Factors
- fibrinogen is associated with increased risk of heart attack
^ PA = decrease in fibrinogen
3.) myocardial oxygen supply & demand
- when “normal” blood flows efficiently
- impeded process: coronary heart disease
oxygen supply in the heart < demand
> plaque (atherosclerosis); inflammation; blood characteristics —-> all contribute to clotting
Myocardial oxygen supply demand
PA and Exercise:
> can reverse “impeded process”
- reduced plaque in arteries
- reduced LDL cholesterol, fats, etc within blood
- Increased HDL
> Anti-inflammatory effects of movement
> Blood becomes less thick
Oxygen supply in the heart better at meeting the demand
temporal sequence
> Prospective cohort design
- Activity or fitness is measured before the
outcome occurs, thus demonstrating the
appropriate temporal sequence.
Prospective cohort studies have
demonstrated consistent associations of
higher activity or fitness levels with lower
CHD risk.
strength of association
> Relative risk of CHD mortality due to inactivity
ranged from 1.5 to 2.4
Active subjects had approximately a 20% to 40%
reduction in CHD risk compared to least active
subjects (PA Guidelines Advisory Committee)
- 40-50% in some studies where PA is measured w/
accelerometers
Information from Population Attributable Risk on previous
slides
consistency of results
> Findings are pretty consistent for men and women.
* Despite using different methodologies and samples
from different parts of the world, studies have
yielded similar results overall.
Biological Plausibility
> As with any biological mechanism – it’s never fully
understood…but we do know enough about certain
mechanisms that allow us to establish a causal link
1. Myocardial Oxygen Supply and Demand
2. Hemostatic (aka blood) and Inflammatory
Biomarkers
Dose Response
Physical Activity
> Curvilinear Dose-Response
Cardiorespiratory Fitness
> Curvilinear Dose-Response as well
general association of PA and mortality
Age: Physical activity during middle age reduces
CHD risk by 30% to 40% for both men and
women
Leisure Time PA:
Most active men have a 22% lower risk of CHD
Most active women have a 33% lower risk of CHD
