[Evaluation of methods for measuring daily physical activity in terms of energy expenditure]

Various methods exist for measuring daily physical activity and daily energy expenditure and daily pedometer readings are most commonly used for the amount of physical activity. In this study, three methods for measuring energy expenditure-24-hr heart rate method (HR), time study method, and caloric expenditure accumulator (CC)-, and the feasibility of a pedometer for the assessment of energy expenditure were examined under laboratory conditions and during normal daily life. Daily physical activity was measured by four methods (HR, Time study, CC, Pedometer) in a field study of 14 young, healthy and sedentary women, and compared. Laboratory validation of the three methods with measurement of oxygen uptake was performed with 5 young men and 1 woman walking and running at different speeds and grades on a treadmill. In addition validation tests of whether pedometer readings reflect differences in energy expenditure due to speed and grade and whether pedometer counts steps exactly were also conducted. The 24-hr energy expenditure derived from CC was significantly lower than that derived from HR and Time study, due to lower estimation of energy expenditure from activities compared to other methods. In the laboratory study, the energy expenditure measured at 5% grade was low by CC and differences in energy expenditure for changes in grade could not be differentiated. Time study revealed a significant relationship between CC and HR in field study. These results suggest that CC tends to underestimate the 24-hr energy expenditure from activity.(ABSTRACT TRUNCATED AT 250 WORDS)