Exploring the link between grit and excessive daytime sleepiness: a study in a population sample

Excessive daytime sleepiness (EDS) is a common condition with implications for individual health and public safety. While factors such as snoring and depression are known contributors to EDS, the role of grit in EDS remains unexplored. This study aimed to investigate the association between and EDS in a representative sample of Korean adults, with a specific focus on the two components of grit: perseverance of effort (PE) and consistency of interest (CI).

A nationwide cross-sectional survey was conducted through door-to-door interviews using structured questionnaires between September and December 2018 in Korea. EDS was assessed using the Epworth Sleepiness Scale, while grit was measured using the Short Grit Scale, comprising PE and CI subscales. Multivariable logistic regression analyses were performed to explore the association between grit and EDS, adjusting for covariates.

A total of 2,356 participants (49.3% male; aged 19-92 years) were enrolled in the study. The prevalence of EDS was 15.2%. Participants with EDS had significantly lower overall grit scores, driven by lower CI subscale scores. After adjusting for confounders, higher grit scores were significantly associated with EDS (OR 0.35, 95% CIs 0.26-0.45, p < 0.001). This association persisted in subgroup analyses, including those with depression and habitual snoring. In contrast, no significant association was observed between the PE subscales and EDS.

Our findings suggest that intrinsic motivation, as reflected by the CI subscale of grit, is inversely associated with EDS. Therefore, exploring interventions that include nurturing grit could be a potential approach to addressing EDS.