Measuring sleep–wake patterns with physical activity and energy expenditure monitors

Abstract

This study assessed the validity of using an energy expenditure actimeter for sleep–wake monitoring. Twelve participants underwent five to nine days of continuous actigraphy, simultaneously wearing an actimeter measuring energy expenditure (Actical) and an actimeter commonly used for sleep–wake assessment (Actiwatch-L) on their non-dominant wrist. Sleep timing variables measured with the two actimeters correlated above 0.90 and the correlation for sleep consolidation variables was above 0.75. Significant positive correlations between the two monitors were also found for an actigraphy based index assessing circadian rhythms. These results support the use of energy expenditure based actimeters to monitor sleep–wake patterns.

Keywords:

• actigraphy
• sleep
• energy expenditure
• circadian rhythms