Objective and subjective measurement of energy expenditure in older adults: a doubly labeled water study

Objective and subjective measurement instruments have been used to estimate energy expenditure (EE) as alternatives to the doubly labeled water (DLW) methodology, but their relative validity for older adults remains uncertain. The purpose of this study was to validate an objective monitor (SenseWear Mini Armband) and a self-report instrument (7-Day Physical Activity Recall, 7D-PAR) relative to the DLW under free-living conditions in older adults.

Twenty-nine older adults (60-78 years) each wore the Mini for 14 consecutive days and completed two 7D-PARs after each week. For each measurement method, activity EE (AEE) was calculated as total EE (TEE)—measured resting metabolic rate (RMR)—diet induced thermogenesis (10% of TEE). TEE and AEE from the Mini and 7D-PAR were each compared with values from the DLW.

Equivalence testing indicated that estimates of TEE from the Mini and the 7D-PAR were statistically equivalent to those measured with DLW; however, differences were evident for estimates of AEE. The Mini had smaller mean absolute percent error for TEE (8.0%) and AEE (28.4%) compared with the 7D-PAR (13.8 and 84.5%, respectively) and less systematic bias in the estimates.

The Mini and 7D-PAR provided reasonably valid estimates of TEE but large errors in estimating AEE. The Mini and 7D-PAR have the potential to accurately estimate TEE for older adults.