Validation of wearable monitors for assessing sedentary behavior

Area of Science:

• Physical activity monitoring
• Health behavior research
• Biomedical engineering

Background:

• Accurate measurement of sedentary behavior (SB) is crucial for understanding its health implications.
• Existing wearable monitors for assessing SB in free-living conditions often lack validated accuracy.
• This study addresses the need for reliable SB assessment tools.

Purpose of the Study:

• To validate commercially available monitors for assessing sedentary behavior.
• To compare the accuracy and sensitivity of activPAL (AP) and ActiGraph GT3X (AG) devices.
• To evaluate different cut-points for the ActiGraph device in defining sedentary behavior.

Main Methods:

• Twenty overweight, inactive office workers participated in two 6-hour observation periods.
• Participants wore both activPAL (AP) and ActiGraph GT3X (AG) monitors.
• Direct observation (DO) was used as the criterion measure, with participants instructed to reduce sitting time during the second period.

Main Results:

• The activPAL (AP) showed high agreement with direct observation (R2 = 0.94) for sedentary time.
• The ActiGraph GT3X (AG) with a 100 counts per minute cut-point underestimated sitting time and had lower agreement (R2 = 0.39).
• The AP demonstrated superior sensitivity in detecting reductions in sitting time, while the AG with 150 counts per minute showed the lowest bias among AG cut-points.

Conclusions:

• The activPAL monitor is more precise and sensitive for assessing sedentary behavior compared to the ActiGraph GT3X.
• Researchers studying sedentary behavior should consider utilizing the activPAL monitor for enhanced accuracy.
• For ActiGraph users, a cut-point of 150 counts per minute may offer a more appropriate definition of sedentary behavior.