ABSTRACT Poor sleep quality is related to difficulties in regulating emotions and to mental health issues in emerging adults. While prior research has confirmed this link, the role of daily fluctuations in sleep quality and emotions, which may require different regulation strategies, has rarely been examined in previous research. This study used Ecological Momentary Assessment (EMA) for seven consecutive days using Research Electronic Data Capture (REDCap), with four smartphone‐based assessments per day administered in the morning after waking, at midday, at 4 p.m., and 1 h before bedtime, to examine how daily average levels (within‐person) and average weekly levels (between‐person) of emotional processes (affect, perceived stress, and emotion regulation difficulties) are related to sleep quality in a convenience sample of 166 emerging adults recruited from a university student population ( M age = 20.36 years, 80.1% female). Linear mixed‐effects models showed that, at the within‐person level, higher daily average levels of anger, anxiety, sadness and perceived stress predicted lower sleep quality, whereas higher daily mean levels of happiness predicted higher sleep quality the subsequent night. At the between‐person level, higher weekly mean levels of anger, anxiety, sadness and perceived stress, as well as more frequent use of rumination, predicted lower sleep quality, while higher mean levels of happiness predicted better sleep quality. To sum up, both daily average and weekly average levels of emotional processes are associated with sleep quality in emerging adults, with mostly negative emotional processes acting as vulnerability factors and happiness emerging as a protective factor.
Ariu et al. (2026) studied this question.