Benefits of Exercise - Cardiovascular Disease

Studying the direct correlation between exercise and various illnesses is significantly more difficult than the previous studies, because of the need to track a large number of people over a long period to obtain a meaningful statistical result. One such study involved 44,000 men aged 40 to 75, enrolled in the Health Professionals' Followup Study. These men were followed for approximately 12 years, and examined at 2-year intervals to assess CHD risk factors, identify newly diagnosed cases of CHD, and assess levels of physical activity. The study finds that the more they exercised, the less rish of CHD they had. For example, compared to inactive men, those who ran for an hour or more a week had a 0.58 Risk Ratio (margin of error between 0.44 and 0.77); men who trained with weights for 30 minutes or more a week had a RR of 0.77 (0.71 to 0.98 margin of error); rowing for 1 hour per week resulted in an 0.82 RR (0.68 to 0.99 margin of error); 30 minutes per day brisk walking was associated with a 0.82 RR (0.67 to 1.00 margin of error, that is barely significant).

Another study (Reference 6) involved almost 74,000 post menopausal women, aged 50 to 79 years. The followup period was approximately 6 years. The study found that brisk walking (or exercise equivalent to...) an hour daily, resulted in a RR of 0.47 (0.33 to 0.67 margin of error), in coronary heart disease. The RR in total cardiovascular disease was 0.72 (0.59 to 0.87 margin of error). The study found that these results were irrespective of race or ethnic group, age, and body-mass index.

The last study we reference in this context (Reference 7), involves the risk of stroke. 72,000 female nurses aged 40 to 65, free of illness at the start, were tracked for 8 years. They found that women with the highest levels of exercise, reduced their risk of stroke by RR=0.66 (0.47 to 0.91 margin of error). Ischemic strokes (the most common type, involving a blockage in blood vessels) were reduced by RR = 0.52 (0.33 to 0.80 margin of error).

The conclusion is unequivocal - while the exact value of the reduction in risk differs from study to study, it is clearly evident that exercise has a major impact in reducing CHD and cardiovascular disease. The different studies also show that intermediate levels of exercise lead to intermediate levels of risk reduction.

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