Self-Reported Sleep Duration, Daytime Sleepiness, and Caffeine Use in Male and Female Morning and Evening Types

Background and Objective Previous studies in adults have focused on differences in sleep timing with respect to morning and evening (ME) types, or gender difference in the distribution of ME types. We aimed to examine sleep habits and behaviors (daytime sleepiness and caffeine consumption) of adult ME types, and to examine whether the factors associated with ME type differed between men and women. Methods Among 1,086 subjects to whom we administered the Korean version of Horne-Ostberg Morningness-Eveningness Questionnaire (MEQ-K), the Korean version of the Epworth Sleepiness Scale (KESS), the Pittsburgh Sleep Quality Index (PSQI) and asked questions about their sleep-wake timing and caffeine use, the data from 911 subjects (age: 38.4 ± 10.9 years, range: 18–88; F: M = 565: 346) were analyzed. Standard scores of the MEQ were used to categorize the subjects as morning type (MT), evening type (ET) and neither type (NT). Results In the overall group, results from the PSQI indicated a significantly shorter sleep duration and greater caffeine consumption in ET when compared to those of MT or NT (p < 0.05). This was also found in the subgroup of women (p < 0.01), but not in the subgroup of men. Daytime sleepiness as reported on the KESS was significantly greater in the ET than the NT or MT overall (p < 0.05) and among the women (p < 0.01), but did not reach significance among men. Conclusions Our study found that ET subjects perceived their sleep quality as poorer than that of MT or NT subjects regardless of gender. We also found that ET women had significantly shorter sleep duration, greater daytime sleepiness, and larger caffeine consumption than MT or NT women, but we did not find the same findings in the men.

Abstract licence: CC BY-NC-ND

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