Sleep Quality and Physical Activity of Night Shift Nurses Working at Hospitals: A Cross-Sectional Survey Study

Background/Objectives: The aim of the study was to explore the specific relationships between sleep quality, physical activity levels, and demographic characteristics (age, education level, and work experience) in night shift nurses working at hospitals. Understanding these relationships is critical for developing evidence-based scheduling, educational initiatives for sleep hygiene, and physical activity programs that can mitigate the negative impacts of night work, ultimately promoting nursing workforce sustainability and safer patient health outcomes. Methods: A cross-sectional design was implemented, involving 400 night shift nurses. Data were collected using a questionnaire, which included an Individual Characteristics Form, the Pittsburgh Sleep Quality Index and the International Physical Activity Questionnaire—Short Form. Results: The sleep quality of night shift nurses differed statistically significantly by age in almost all sub-scales (p < 0.001) except for the sub-scale “habitual sleep efficiency”. A significant difference was found across groups, with sleep latency (p = 0.038 *) increasing as work experience grew. Nurses with more experience utilized sleep medications (p = 0.014 *) more frequently than less experienced ones. Physical activity levels differed significantly (p < 0.05): the youngest group showed a higher proportion of high physical activity (52.3%) compared to the oldest (28.9%). A statistically significant negative correlation was found between total physical activity and the total PSQI score (r = −0.162, p = 0.001). Conclusions: The data show that night shifts consistently disrupt nurses’ sleep, and advancing age further compounds these difficulties. The elevated total Pittsburgh Sleep Quality Index (PSQI) scores verify severe sleep disruption across the sample. Physical activity operates as a beneficial behavioral modifier that significantly relates to better sleep quality, lower sleep latency, and less frequent use of sleep medications among night shift nurses.