Effects of the gradually increasing dawn light stimulation on sleep feeling

Effects of a new lighting stimulation system upon subjective sleep and waking feeling were psychophysiologically examined in 24 healthy students in order to develop a way of obtaining comfortable awakening. The subjects underwent three different experimental conditions: the light stimulation condition, non-light stimulation condition and the control condition. The satisfaction of sleep was higher and day sleepiness lower in the light condition compared with the other two conditions. Subjective fatigue related to mental functions at waking was also smaller in the light condition compared with the other two conditions. These results suggest that the improvement of sleep feeling and waking seems to be achieved by gradual increased dawn light stimulation.