Experimental design
The present study was an open-label, randomized crossover trial consisting of the SJL and control (CON) trials (Figure SAfter written informed consent was obtained, wearable devices (Fitbit Charge 5, Fitbit, CA, USA) were distributed to the participants to monitor sleep variables and energy balance throughout this study. The device automatically measures bedtime, awake time, sleep duration (percentage of time in rapid eye movement [REM], light and deep sleep), and daily total energy expenditure. The validity of Fitbit Charge series for measuring the sleep variables has been confirmed by comparison with polysomnography and actigraphy [