Is daily emotion suppression associated with poor sleep? The moderating role of culture.

Emotion suppression is widely assumed to be unhealthy. Yet, this conclusion may be limited to independent Western cultures that value self-expression. In a pre-registered, daily diary study of European American and East Asian college students, we tested whether culture moderates the effects of daily use of emotion suppression on sleep-a critical component of healthy living among young adults. A total of 117 college students (62 European Americans and 55 East Asians) completed two diaries per day for 14 days to assess (a) their daily use of emotion suppression every night and (b) subjective sleep quality and mood upon awakening every morning. Participants also wore actigraphy watches to provide behavioral measures of sleep. The data were collected between 2018 and 2020. We used multilevel models to test cultural differences in the effects of emotion suppression on sleep and mood measures at both between-person (average) and within-person (day-to-day) levels. For European Americans, greater use of emotion suppression across 2 weeks was associated with lower average subjective sleep quality and more tense (vs. calm) feelings upon awakening. At the within-person level, on days when European Americans used emotion suppression more than usual, they had less amount of sleep that night. In contrast, these associations were completely absent among East Asians. These results provide support for the cultural fit hypothesis that how emotion suppression affects sleep health varies by cultural contexts, depending on whether this regulatory behavior is normatively congruous or incongruous with the values prioritized in each culture. (PsycInfo Database Record (c) 2023 APA, all rights reserved).