The Harvard alumni health study is a cohort study focusing on the effect of

exercise Exercise is a body activity that enhances or maintains physical fitness and overall health and wellness. It is performed for various reasons, to aid growth and improve strength, develop muscles and the cardiovascular system, hone athletic ...

coronary artery disease Coronary artery disease (CAD), also called coronary heart disease (CHD), ischemic heart disease (IHD), myocardial ischemia, or simply heart disease, involves the reduction of blood flow to the heart muscle due to build-up of atherosclerotic pla ...

, strokes, diabetes,

hypertension Hypertension (HTN or HT), also known as high blood pressure (HBP), is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms. Long-term high bl ...

, cancer, obesity and

mortality Mortality is the state of being mortal, or susceptible to death; the opposite of immortality. Mortality may also refer to: * Fish mortality, a parameter used in fisheries population dynamics to account for the loss of fish in a fish stock throug ...

. Including only male, Harvard College graduates who began their studies between 1916 and 1950 and were still living in 1966, the study began with 21,582 individuals. Data was collected on the lifestyle and health of these men in 1962, 1966, 1977, 1988, and 1993, at which point only 11,894 men remained in the study. As with all cohort studies, the narrow catchment criteria for participants was both a strength and a weakness: selecting only educated, middle-aged, predominantly white males lent the study greater power to see statistically significant results in that demographic, but left it blind to broader reaching phenomena. Fit people did better and had less disease than unfit people. If people changed from unfit to fit their disease risk went down.

References

*{{cite book , author=Simon, Harvey B. , title=The Harvard Medical School guide to men's health , publisher=Free Press , location=New York , year=2002 , page
37–8
, isbn=0-684-87181-5 , oclc= , doi= , url-access=registration , url=https://archive.org/details/harvardmedicalsc00simo/page/37 Alumni health study Cohort studies