The Yale Physical Activity Survey for older adults: predictions in the energy expenditure due to physical activity

Objective: To evaluate the accuracy of the Yale Physical Activity Survey (YPAS) for older adults. Design: Fourteen-week strictly controlled diet study. Subjects/setting: Eleven men and 17 women, age range 55 to 78 years, spent 10 weeks in an outpatient setting and 4 weeks in an inpatient setting at the General Clinical Research Center, Noll Physiological Research Center, The Pennsylvania State University, University Park. Intervention: Subjects were provided dietary energy to maintain body weight within ±0.5 kg of baseline weight. The daily menus contained 0.8 g protein per kilogram body weight and nonprotein energy as 60% carbohydrate and 40% fat. Main outcome measures: Metabolizable energy intake (MEI) was measured at week 14 from the gross energy contents of food, urine, and feces, with corrections for any body composition changes during the last 6 weeks of weight maintenance. Resting energy expenditure (REE) was determined using indirect calorimetry. The thermic effect of feeding (TEF) was estimated to be 10% of the MEI. The energy expenditure due to physical activity (EEPA) was derived by the formula: EEPA=MEI-REE-TEF. This value was compared with the EEPA estimated from the YPAS. Statistical analyses performed: Two-factor analysis of variance with repeated measures and paired t tests. Results: At week 14, after a minimum of 6 weeks of sustained weight stability, the derived EEPA was not different from that estimated using the YPAS for the men and the men and women combined, while the YPAS estimate was more than the measured mean value for the women (P<.05). There was wide variability in the accuracy of the EEPA prediction for individual subjects (range=-637 to 794 kcal). Applications/conclusions: The YPAS may be used, with caution, to estimate the EEPA for groups of older individuals, and may provide inaccurate estimates of the EEPA in older individuals.