Narrowing of a coronary artery by a large plaque of atheroma
Natural history of atherosclerosis: from fatty streak to clinical ‘horizon’
Mortality from CHD in San Francisco dockworkers
Rates of first heart attack in Harvard Alumni, according to current physical activity and participation as student
Only current physical activity is protective – sports participation in youth does not confer protection in middle-age unless activity is maintained
CHD rates in civil servants: effect of exercise holds across confounding factors
Source: Morris et al. (1990).
Note: Groups indicate level of vigorous exercise: 1, highest, 4 lowest
Relative risk for CHD in men: evidence for dose–response
Source: Health Professionals Follow-up Study (2002).
Changes in activity or fitness are associated with changes in risk
Cohort studies have reported assessments of physical activity or fitness made several years apart.
Harvard Alumni who were sedentary on first observation but became physically active had a lower risk than those who remained sedentary.
In the Aerobics Center Study, men who were unfit on first assessment but had improved their fitness five years later experienced a much lower CVD risk than those who remained unfit.
The relationship between physical activity/fitness and risk for CHD is:
Dyslipidaemia: elevated total cholesterol or low-density lipoprotein cholesterol concentrations, depressed high-density lipoprotein cholesterol concentrations, elevated triglyceride concentrations
Hypertension
Cigarette smoking
Obesity (particularly central/abdominal obesity)
Hyperglycaemia or diabetes
Non-modifiable risk factors
Family history: risk is increased in first degree relatives (parents, siblings and offspring) of people with premature atherosclerotic disease (men < 55 years and women < 65 years)
Age: higher risk in older individuals
Gender: higher risk in males than females
Ethnic background: higher risk in South Asians although this may be due to the higher prevalence of diabetes in this group
Prevalence of major risk factors in Great Britain/England
Composition of the four major lipoprotein classes
Plasma HDL-cholesterol in groups differing in level of habitual activity
Cardiovascular diseases are a major cause of mortality and morbidity in developed countries, and their prevalence is increasing in developing countries.
Atherosclerosis is the major cause of CVD. It has a long clinical history and may be well-progressed before symptoms occur.
Inactivity and low fitness are strong risk factors for CHD. Both confer an increase in risk similar to that associated with smoking, hypertension and high blood cholesterol.
Summary II
Being physically active or fit may reduce the risk of having a stroke.
Mechanisms by which physical activity may modify CVD risk include effects on lipoprotein metabolism, blood pressure and endothelial function.
Physical activity is a central component of cardiac rehabilitation. Exercise training may enhance myocardial perfusion and hence oxygen delivery to the heart.
Exercise reduces symptoms of claudication and heart failure and may help to lower blood pressure in hypertensive individuals.
