Document Type



The purpose of this review is to provide the reader with a current “state-of-the-art” in the assessment of habitual physical activity in human subjects. A discussion of the direct measurement of physical activity includes the use of observations, diaries, instruments and questionnaires. Most investigators of habitual physical activity in populations are usually interested in energy expenditure; hence the usefulness of direct measurements of energy expenditure are described and the possibilities and limitations of estimates of energy expenditure based on physiological observations are summarized.