“…The lighting interventions in the experimental groups differed in lighting equipment, illuminance (in units of lux), lighting time points, exposure duration, spectrum wavelength, and color. Eight studies [ 22 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ] applied lighting with a color temperature greater than or equal to 5000 K and three applied lighting with a color temperature below 5000 K [ 33 , 34 , 35 ]. In terms of sleepiness assessment, 12 studies adopted the KSS [ 11 , 13 , 22 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 34 , 36 ], and 2 [ 33 , 37 ] adopted the Stanford Sleepiness Scale (SSS), as seen in Table 1 .…”