Table 2.
Comparison with previous studies.
| Indicators | Steps | Distance | Activity duration | EEa | Sleep duration |
Deep sleep duration |
| This study | Excellent consistency with CVb (2-38%) | Excellent consistency with CV (5-30%) | Fair consistency with CV (19-112%) |
Fair consistency with CV for total EE (.1-17%) and activity EE CV (22-100%) | Poor consistency with CV (2-44%) |
Poor consistency with CV (35-117%) |
| Previous studies | Consumer-grade wearable devices provided consistently similar step counts with research-grade devices for average daily activity (P>.05) [21] | The inter-device reliability of wearable devices in measuring distance was excellent for all treadmill speeds (ICCc≥.90) [14] | Consumer-level wearable devices showed moderate validity for measurement of moderate to vigorous physical activity in free-living conditions (r=.52-.91) [16] | Consumer-level wearable devices showed moderate validity for measurement of total daily EE in free-living conditions (r=.74-.81) [16] | Consumer-level wearable devices showed strong validity for measurement of sleep duration in free-living conditions (r>.8) [16] | Consumer-grade wearable devices showed good agreements with PSGd for sleep efficiency, and they overestimated PSG sleep efficiency slightly [22] |
| The inter-device reliability of wearable devices in measuring steps in free-living conditions is good (ICC≥.90) [23] | Distance errors in wearable devices were within 5% in level walking, and they overestimated distance for stair walking by at least 45% [24] | Consumer-grade wearable devices can’t accurately capture activity data across the entire 24-h day, error rates ranged from 51.8% to 92% for moderate to vigorous physical activity [17] | Consumer-grade wearable devices reasonably and reliably estimate EE during walking and running (ICC≥.95) [25] | Consumer-grade wearable devices performed consistently compared with each other (reliability=96.5-99.1%), and they overestimated sleep time by an average of 67.1 min compared with PSG [26] | Consumer-grade wearable devices performed consistently compared with each other (reliability=96.5%-99.1%), and they overestimated sleep efficiency by an average of 14.5% compared with PSG [26] |
aEE: energy expenditure.
bCV: coefficient of variation.
cICC: intraclass correlation coefficient.
dPSG: Polysomnography.