Direct Observation Can Be Used to Measure Energy Expenditure
Mentor 1
Scott Strath
Start Date
10-5-2022 10:00 AM
Description
Indirect calorimetry (IC) is a precise method for measuring energy expenditure (EE), but IC can often be infeasible or inaccessible to researchers. Compared to IC, direct observation (DO) is a method that is much more cost effective, can be employed in field settings, and provides qualitative insight on physical activity (PA) behavior. In this study we sought to determine if DO is a suitable proxy for IC on non-sedentary activities by comparing video recorded DO estimates to IC room chamber EE values. 10 participants were video recorded over a 12-hour IC chamber stay. During the chamber stay all participants engaged in typical free-living behaviors that included simulated occupational tasks, household tasks, and leisure-time tasks. All videos were analyzed in Noldus Observer XT14 to differentiate physical activities, postures, and intensities of activity movement. For statistical analysis, non-sedentary activity behaviors ≥ 1 minute were examined. Percent bias with 95% confidence intervals of light and moderate-to-vigorous physical activity (MVPA) DO intensities were compared to IC. The average length of the videos were 659.19 minutes, and the average active time was 155.49 minutes. DO underestimated time spent in the light intensity by -8.96% (-27.82%, 9.83%) and overestimated MVPA time by 3.69% (-30.03%, 37.41%). This study provides evidence that DO can be used as a suitable criterion for estimating EE. Future directions include extending the validity of DO to assess EE in populations other than healthy individuals, and to examine the validity of DO in true free-living settings.
Direct Observation Can Be Used to Measure Energy Expenditure
Indirect calorimetry (IC) is a precise method for measuring energy expenditure (EE), but IC can often be infeasible or inaccessible to researchers. Compared to IC, direct observation (DO) is a method that is much more cost effective, can be employed in field settings, and provides qualitative insight on physical activity (PA) behavior. In this study we sought to determine if DO is a suitable proxy for IC on non-sedentary activities by comparing video recorded DO estimates to IC room chamber EE values. 10 participants were video recorded over a 12-hour IC chamber stay. During the chamber stay all participants engaged in typical free-living behaviors that included simulated occupational tasks, household tasks, and leisure-time tasks. All videos were analyzed in Noldus Observer XT14 to differentiate physical activities, postures, and intensities of activity movement. For statistical analysis, non-sedentary activity behaviors ≥ 1 minute were examined. Percent bias with 95% confidence intervals of light and moderate-to-vigorous physical activity (MVPA) DO intensities were compared to IC. The average length of the videos were 659.19 minutes, and the average active time was 155.49 minutes. DO underestimated time spent in the light intensity by -8.96% (-27.82%, 9.83%) and overestimated MVPA time by 3.69% (-30.03%, 37.41%). This study provides evidence that DO can be used as a suitable criterion for estimating EE. Future directions include extending the validity of DO to assess EE in populations other than healthy individuals, and to examine the validity of DO in true free-living settings.
