ABSTRACT
Cohort studies that started in the late 1960s discovered that, as an epidemic condition in Western countries, coronary heart disease (CHD) (the cardiovascular disease (CVD) with the highest prevalence) is largely due to environmental influences. This is not to deny the importance of genetic predisposition in modifying susceptibility. However, for most individuals, CHD is caused as much or more by ‘nurture’ as it is by ‘nature’. One environmental influence which is related to CHD is physical activity. In the last chapter we examined evidence which showed that people who are physically active or fit are less likely to die over a defined period than those who are inactive and/or unfit. This chapter shows that one important reason for this is that individuals who are active and fit experience a lower incidence of CVD. More than 50 years after Professor Jeremy Morris’ pioneering studies, the evidence that physical inactivity and low fitness are risk factors for CVD is compelling. We will now evaluate this evidence in accordance with the principles set out in Chapter 2. First, however, it is important to clarify the term CVD.
