Sleep Habits, Physical Exercise, and Social Media Use and Their Influence on Perceptions of Physical and Mental Health—Case Study at a Higher Education Institution in Portugal

<b>Background/Objectives:</b> The transition to higher education is often accompanied by lifestyle changes that may influence sleep habits, physical activity, and social media use, with potential consequences for physical and mental health. <b>Methods:</b> A quantitative, cross-sectional, descriptive, and correlational study was conducted using an online questionnaire administered between April and May 2024. The sample included 201 participants (123 students and 78 teaching/non-teaching staff). Data were collected using the Mental Health Inventory-5 (MHI-5), Social Media Addiction Scale (SMAS), Global Physical Activity Questionnaire (GPAQ), and Pittsburgh Sleep Quality Index (PSQI). Descriptive statistics and Spearman correlation analyses were performed. <b>Results:</b> Students presented lower mental health scores compared to staff members. Sleep quality indicators, particularly reduced sleep efficiency and increased use of sleep medication, were significantly associated with poorer mental health. Correlations between physical activity, social media use, sleep quality, and mental health were generally weak, suggesting that these domains contribute independently to perceived well-being. Staff members showed slightly higher levels of social media addictive behaviors, while students reported shorter sleep duration and greater emotional variability. <b>Conclusions:</b> The findings indicate that students presented lower mental health scores and poorer sleep indicators compared to staff members. Sleep quality-particularly sleep duration, efficiency, and use of sleep medication-showed the most consistent associations with mental health, while physical activity and social media use demonstrated weaker relationships. These results highlight the relevance of targeted sleep-focused interventions within higher education settings, especially for students in low-density regions.