Abstract
Correlations between subjective sleep latency evaluated at the time of waking and objective sleep latency by polysomnography, sleep stage appearance ratio, and subjective sleep feelings at the time of waking were investigated in healthy young male adults. The authors re-analyzed the data recorded in the experiment that evaluated the light environment before sleep, and examined the data for 150 nights measured from 8 to 10 nights per participant and the mean values calculated for each of the 16 participants.
Looking at the daily fluctuations in subjective sleep latency, the first-night effect was not clear, and the time interval of self-evaluation tended to change according to the length of subjective sleep latency. Correlation analysis of data from 16 participants showed that subjective sleep latency had a significant moderately correlation with each objective sleep latency obtained from PSG, and showed the strongest correlation with Stage 2 latency. Furthermore, there was a significant positive correlation with the occurrence rate of Wake in the first segment of sleep divided into four, and a significant moderately negative correlation with OSA factor IV (integrated sleep) in the subjective sleep feelings upon awakening. In addition, some of the participants with short objective sleep latency estimated longer subjective sleep latency, and it is thought to be related to lower subjective sleep feelings.
From the above results, the sleep state at the beginning of sleep is subconsciously memorized to a certain extent, and the results recalled when waking up are reflected in the subjective sleep latency. Furthermore, it is suggested that the integrated sleep feeling is strongly involved to the subjective sleep latency. In conclusion, by measuring and recording one person over multiple nights, it is expected that we have obtained new knowledge that will contribute to sleep evaluation methods in daily life.
https://ror.org/00965ax52 
