Evaluation of Sleep Parameters and Sleep Staging (Slow Wave Sleep) in Athletes by Fitbit Alta HR, a Consumer Sleep Tracking Device

Figures & data

Table 1 Characteristics of the Participants

	N = 36
Age, years	21.0 ± 0.9
Gender (%)	Male 17 (47.2%) female 19 (52.8%)
BMI, kg/m^2	22.5 ± 1.8
SDB	3 (8%)
AHI, event/h of sleep	2.1 [3.0]

Note: Continuous variables were summarized using mean ± SD or median [interquartile range].

Abbreviations: BMI, body mass index; SDB, sleep-disordered breathing; AHI, apnea-hypopnea index.

Table 2 Results of Paired t-Test Between Sleep Parameters of EEG and Those of FBA

	TST (Min)	SOL (Min)	N3 (%)	N3 in Between Sleep Onset and Initial REM Sleep (%)	Arl (Events/h of Sleep)
EEG(ZA-9)	346.5±47.0	21.9±15.9	22.7±7.6	50.3±19.4	8.4±3.0
FBA	338.4±46.4	5.1±4.8	20.7±5.3	42.4±14.0	4.2±1.0
P value	0.08	<0.001	0.03	0.001	<0.001

Note: Continuous variables were summarized using mean ± SD.

Abbreviations: Arl, arousal index; EEG, electroencephalography; FBA, Fitbit Alta HR^TM; REM, rapid eye movement; SOL, sleep onset latency; TST, total sleep time.

Figure 1 (A) Scatter plot of the total sleep time (TST) derived from the electroencephalograph (TST-EEG) and the TST from Fitbit Alta HR (TST-Fitbit) There is a strong correlation between the TST-EEG and the TST-FitBit. (B) Bland-Altman plots according to the TST The Y-axis indicates the difference between the TST-EEG and the TST-Fitbit [(TST-EEG)- ([TST-Fitbit)]. The X-axis indicates the mean values. The solid line represents the mean difference; the dashed lines represent the limit of agreement. (C) Scatter plot of the sleep onset latency (SOL) derived from the electroencephalograph (SOL-EEG) and the SOL from Fitbit Alta HR (SOL-Fitbit) There is a weak correlation between the SOL-EEG and the SOL-FitBit. (D) Bland-Altman plots according to the SOL The Y-axis indicates the difference between the SOL-EEG and the SOL-Fitbit [(SOL-EEG)- (SOL-Fitbit)]. The X-axis indicates the mean values. The solid line represents the mean difference; the dashed lines represent the limit of agreement.

Figure 2 (A) Scatter plot of the N3 sleep derived from the electroencephalograph (N3-EEG) and the N3 from the Fitbit Alta HR (N3-Fitbit) There is a modest correlation between the N3-EEG and the N3-FitBit. (B) Bland-Altman plots according to N3. The Y-axis indicates the difference between the N3-EEG and the N3-Fitbit [(N3-EEG) - (N3-Fitbit)]. The X-axis indicates the mean values. The solid line represents the mean difference; the dashed lines represent the limit of agreement. (C) Scatter plot of the percentage of N3 in between sleep onset and initial REM derived from the electroencephalograph (the percentage of N3 in between sleep onset and initial REM sleep-EEG) and those from Fitbit Alta HR (the percentage of N3 in between sleep onset and initial REM sleep-Fitbit). There is a strong correlation between the percentage of N3 in between sleep onset and initial REM sleep-EEG and the percentage of N3 between sleep onset and initial REM sleep-FitBit. (D) Bland-Altman plots according to the percentage of N3 in between sleep onset and initial REM sleep The Y-axis indicates the difference between the percentage of N3 in between sleep onset and initial REM sleep-EEG and the percentage of N3 between sleep onset and initial REM sleep-FitBit. The X-axis indicates the mean values. The solid line represents the mean difference; the dashed lines represent the limit of agreement.

Figure 3 (A) Scatter plot of the arousal index (Arl) derived from the electroencephalograph (Arl-EEG) and the Arl from Fitbit Alta HR (Arl-Fitbit) There is a weak correlation between the Arl-EEG and the Arl-FitBit. (B) Bland-Altman plots according to Arl The Y-axis indicates the difference between the Arl-EEG and the Arl-Fitbit [(Arl-EEG)- (Arl-Fitbit)]. The X-axis indicates the mean values. The solid line represents the mean difference; the dashed lines represent the limit of agreement.