ENERGY-EXPENDITURE AT REST AND DURING STANDARDIZED ACTIVITIES - A COMPARISON BETWEEN ELDERLY AND MIDDLE-AGED WOMEN

To estimate energy expenditure (EE) in elderly subjects, more age-spec ific data are required on energy costs of standardized activities. EE was assessed by using indirect calorimetry in 28 women aged 72 +/- 4 y (xBAR +/- SD) and in 29 middle-aged women (42 +/- 1 y) at rest (resti ng metabolic rate; RMR) and during sitting, sitting with standardized arm activity, and walking on a treadmill at 3 km/h. RMR and EE during sitting, and sitting with standardized arm activity did not differ sig nificantly between the groups, although EE expressed as a ratio of arm activity to RMR (physical activity ratio, PAR) tended to be higher in the elderly subjects. Walking EE was significantly higher in the elde rly women (16.4 +/- 4.0 kJ/min) than in the middle-aged women (12.7 +/ - 2.3 kJ/min), also when expressed as PAR. It is suggested that elderl y women walk less efficiently. Because PARs are frequently used to est imate daily EE, it is important to note that additional age-specific d ata might be required.