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. Author manuscript; available in PMC: 2022 Jul 1.
Published in final edited form as: Chronobiol Int. 2021 Apr 1;38(7):1010–1022. doi: 10.1080/07420528.2021.1903481

Figure 2.

Figure 2.

Fitbit Charge 3™ heart rate by polysomnographic sleep stage (a) and predicted probability of epoch-by-epoch (EBE) transition agreement by absolute Fitbit Charge 3™ heart rate changes to polysomnographic EBE transitions (b), in the sample of healthy sleepers. FC3, Fitbit Charge 3™, PSG, polysomnography, HR, heart rate; bpm, beats per minute; “light”, PSG-based N1 + N2 sleep; “deep”, PSG-based N3 sleep; REM, Rapid-Eye-Movement sleep. Figure (a) shows the distribution of FC3 HR values averaged by participant (gray dots) for each PSG sleep stage (error bars indicate 95% confidence intervals). Figure (b) shows the predicted probabilities (with 95% confidence intervals) of EBE transition agreement depending on absolute percent FC3 HR change to transitions between consecutive epochs classified with the same stage (solid red line) or with different stages (solid blue line) by the PSG.