The Effect of Bright Light Intervention on Sleepiness and Oral Temperature of Night Health Care Workers in Hospital: A Clinical Trial Study

Background: Productivity and safety of night shift workers are affected by sleepiness during work. Therefore, interventions to reduce sleepiness are very important. This study was conducted with the aim of determining the effect of light on sleepiness and mouth temperature of hospital night shift workers. Materials and Methods: This clinical trial study was conducted using light intensity intervention in 140 hospital night shift workers in 2018 with targeted sampling. The Stanford Sleepiness Scale (SSS) was used to determine the sleepiness score. This scale was completed one hour after light interventions at 23 and 1, 3 and 5 in the morning. Also, mouth temperature was measured one hour after starting work at 23, 1, 3, 2, and 4. Finally, the data before and after the intervention were compared and the results were analyzed. Results: The average sleepiness and mouth temperature were 1.04±2.67 and 36.56±0.13, respectively. The effect of the intervention on sleepiness was significant (P-value 0.001). The correlation between mouth temperature and sleep was significant (0.033, r = 0.22, P-value). The trend of changes in employees’ oral temperature was also significant (P-value 0.001). Conclusion: The results showed that the light intensity had a significant effect on sleepiness. But there was no significant effect of light intensity on the mouth temperature of employees and there was a significant inverse relationship between sleepiness and mouth temperature.