Sleep Quality and Associated Lifestyle Factors Among Medical Students Before and After the COVID-19 Era—A Comparative Study from Romania

Background and Objectives: Sleep is a vital psychological function for health and well-being in all age groups, from children to adolescents, to adults and the elderly, and impacts quality of life. This study evaluated temporal changes in sleep quality and lifestyle behaviors among medical students in North-Western Romania (Transylvania) between the COVID-19 pandemic and the post-pandemic period. Materials and Methods: A cross-sectional design was employed involving 709 medical students assessed during the first pandemic wave (2020) and the 2023–2024 academic year. Online questionnaires collected data on demographics, body mass index (BMI), substance use, and physical activity. Sleep quality was measured using the validated Athens Insomnia Scale (AIS), and multiple linear regression was performed to identify predictors of sleep outcomes. Results: Post-pandemic data revealed a significant decline in sleep quality, with female gender and lower academic performance identified as significant predictors of insomnia symptoms (R2 of 0.258, p < 0.05). While physical activity levels improved significantly in 2024 compared to the confinement period, this was accompanied by increased fast-food consumption and a rise in overweight and obesity rates. Conversely, illicit drug use decreased, and alcohol consumption patterns shifted, characterized by reduced weekly frequency among females but persistent binge drinking episodes. Conclusions: The transition to post-pandemic education yielded mixed health outcomes; while physical activity rebounded, sleep quality and nutritional status deteriorated. These findings highlight the necessity for university-based interventions focusing on sleep hygiene, nutrition, and stress management to support the well-being of medical students.