A History of Physical Activity Measurement in Epidemiology

Abstract

Although Hippocrates is often considered the father of epidemiology, John Snow also played an important role with his studies of cholera epidemics in Victorian London. A detailed study of relationships between physical activity and the prevention of chronic disease did not begin until the mid-twentieth century, with Jeremy Morris in London, and Henry Taylor and Ralph Paffenbarger in the U.S. leading investigations of the epidemic of ischaemic heart disease. Occupation or athletic status was initially used to classify the habitual physical activity of study participants, but as daily energy expenditures diminished at most work sites, interest shifted to questionnaire and diary assessments of leisure activity. Other options to classify the habitual activity of subjects included occasional quasi-experimental assignments to exercise programmes, determinations of aerobic fit-ness, and a study of " natural experiments " where community activity patterns were known to have diminished. Such initiatives generally distinguished active from inactive individuals, but attempts to determine the intensity and volume of exercise that was undertaken often yielded unrealistically large values. The introduction of modern pedometer/accelerometers at first seemed to promise accurate, objective assessments of habitual activity. Although quite successful in assessing standard-ized activities such as steady walking, the newer monitors have shown much less consistency in measuring the wide range of activities encountered in normal daily living. Future research may focus upon some combination of activity monitoring with global position-sensing and posture detecting devices.