Harmonization of three different accelerometers to classify the 24 h activity cycle

Area of Science:

• Chronobiology and Physical Activity Measurement
• Biomedical Engineering and Wearable Technology

Background:

• Accurate measurement of the 24-hour activity cycle (24-HAC), encompassing sleep, sedentary behavior (SED), light physical activity (LPA), and moderate to vigorous physical activity (MVPA), is crucial.
• Existing methods using single wrist-worn accelerometers or self-report instruments have limitations in accuracy and are prone to recall errors.

Purpose of the Study:

• To assess the feasibility and logistical challenges of harmonizing data from multiple research-grade accelerometers to improve 24-HAC measurement.
• To develop an algorithm for combining data from wrist, thigh, and hip accelerometers for a comprehensive 24-HAC assessment.

Main Methods:

• 108 participants wore three accelerometers (ActiGraph GT9X on wrist, activPAL3 on thigh, ActiGraph GT3X+ on hip) for 7-10 days.
• Participant compliance was monitored, and an algorithm was developed to harmonize data from the three devices.
• The resulting 24-HAC estimates were analyzed for within-day and between-day variations.

Main Results:

• High data usability was achieved (94.3%–96.7% for individual devices, 89.4% for all three).
• Harmonized data indicated university students spent approximately 34% sleeping, 41% sedentary, 21% in LPA, and 4% in MVPA.
• Significant variations in activity patterns were observed across different times of day and days of the week.

Conclusions:

• Combining multiple accelerometers is a feasible approach to derive harmonized and more accurate estimates of the 24-HAC.
• This multi-device strategy can minimize data gaps but necessitates consideration of increased research costs and participant/investigator burden.