Sleep Quality and Nutritional Intake in Subjects with Sleep Issues According to Perceived Stress Levels

Background Sleep disorders can negatively affect quality of life with reduced cognitive function. Since stress and eating behavior are considered crucial factors for sleep, this study's aim was to compare objective quality of sleep and nutrition between subjects with sleep issues and different stress levels. Methods The investigation was performed in adults (≥18 years old) in the Sleep Laboratory between September 2015 and February 2016. Several measurement instruments were utilized, including the Pittsburgh Sleep Quality Index (PSQI), the Korean version of the Brief Encounter Psychosocial Instrument (BEPSI-K), polysomnography, and a food frequency questionnaire (FFQ). Results There were no statistical differences in demographic data between the lower and higher stress groups except age, which was adjusted. Sleep quality in the lower stress group was better than the higher stress group in terms of sleep efficiency (90.92 ± 7.72 vs 85.36 ± 10.25%), sleep latency (16.94 ± 20.86 vs 9.42 ± 8.24 min), and WASO result (26 ± 26.13 vs 43.66 ± 41.32 min). There were statistically significant differences in nutritional intake between the groups: the lower stress group consumed more vegetables than the higher stress group while the higher stress group consumed more grains, meat and eggs, soju, and coffee products than the lower stress group. Conclusion This study found that stress level and food intake have significant associations with objective sleep quality. Food and stress management for insomnia should be considered for improving not only quantity but also quality of sleep.