Circadian Phase Assessment of Core Body Temperature Using a Wearable Temperature Sensor Under the Real World.

Abstract

Objective: To evaluate whether a patch-type wearable temperature sensor (CALERA Research) could determine the circadian phase of core body temperature (CBT) in a manner like a rectal probe.

Objective: Sixteen participants (27 ± 11 years, 8 males and 8 females) wore an actigraph and CALERA Research sensor on the chest region for 3-5 days in a real-world setting. Simultaneous rectal temperature measurements were performed during the nocturnal sleep period. The midpoints of the nocturnal decrease in CBT (CBT _trough ) were used as the circadian phase marker. We analyzed 60 pairs of CBT _trough . The reliability and agreement of the CBT _trough from the two devices were analyzed using the intraclass correlation coefficient (ICC) and the concordance correlation coefficient (CCC). The Bland-Altman analysis was used to quantify the limit of agreement of CBT _trough between the devices.

Objective: The ICC of 0.96 (95%CI: 0.93-0.98) and CCC of 0.96 (95%CI: 0.93-0.97) values indicated excellent reliability and substantial agreement, respectively. The mean bias was 0.16 hours (95%LoA: -0.76-1.07 hours). The mean CBT _trough comparison was 5.9 ± 1.6 hours in the CALERA Research sensor and 5.8 ± 1.7 hours in the rectal probe.

Conclusion: The difference in the CBT _trough between the two devices was about ± 1.0 hour which would be an acceptable range for determining the CBT _trough . We suggest that the CALERA Research sensor could be a useful tool for reasonably estimating the circadian phase of CBT _trough and providing a surrogate for a rectal probe.