Validation and reliability of two activity monitors for energy expenditure assessment

Objectives: 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).

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

Methods: 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.

Results: 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).

Conclusion: 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.