Validation and reliability of two activity monitors for energy expenditure assessment

This study explores the reliability and validity of the SenseWear Armband (SWA) and Actical (ACT) for free-living total energy expenditure, and energy expenditure during rest and light-to-moderate exercises (walking, ergocycling).

Participants wore the 2 devices during 7 days (free-living) and then participated to 3 days of testing in our laboratory.

SWA and ACT estimates of total energy expenditure was compared to the doubly labeled water technique (7 days), and energy expenditure during rest (60min), treadmill (45min; intensities ∼22% to ∼41% VO2peak) and ergocycling (45min; ∼50% VO2peak) were compared to indirect calorimetry over the following 3 days. Paired T-tests and intra-class correlation coefficient (ICC) with 95% confidence interval (CI95) were computed.

Twenty adults were recruited (BMI 23.1±2.3kg/m(2)). Compared to doubly labelled water, SWA overestimated energy expenditure by 94kcal/d (±319; P=0.2) and ACT underestimated by -244kcal/d (±258; P=0.001). Energy expenditure during rest (SWA 210±116, ACT 124±133kcal/d; p<0.05) and treadmill (according on intensity: SWA 54±46 to 67±38, ACT 68±25 to 84±40kcal; p<0.05) were overestimated and underestimated during ergocycling (SWA -93±65, ACT -269±111kcal; p<0.05) compared to indirect calorimetry. High ICC were observed at rest (SWA 0.994 CI95 0.987-0.997; ACT 0.998 CI95 0.996-0.999) and during ergocycling (SWA 0.941 CI95 0.873-0.975; ACT 0.854 CI95 0.687-0.939).

Acceptable estimation of total energy expenditure was observed with the SWA. Both devices were reliable but not accurate for energy expenditure's estimations during rest and for specific exercises.