Association between Lifestyle Habits (Physical Exercise, Sleep, BMI, and Tobacco Consumption) and Academic Performance in Spanish University Students: A Cross-Sectional Study

Healthy lifestyle habits are a key pillar of physical, psychological, and social well-being, yet university years are often marked by declines in sleep quality, physical activity, and other health behaviors that may affect academic performance. This cross-sectional study examined these associations in 390 Spanish university students, assessed via an online and in-person questionnaire covering academic trajectory (grade point average, credits passed, curricular progression), sleep quality (PSQI), physical activity (IPAQ), tobacco use, Body Mass Index (BMI), and sociodemographic data. Bivariate associations were tested with chi-square, Pearson correlation, t-tests, and ANOVA, followed by generalized linear models for significant variables. Sports participation, but not IPAQ-measured physical activity, was significantly associated with academic progression, defined as advancing one grade level per year. Sleep indicators showed mixed, partly counterintuitive associations: poorer nocturnal sleep was linked to better progression, whereas better sleep quality predicted a higher percentage of credits completed. BMI was a modest positive predictor of credit completion, and underweight students performed significantly worse than overweight or obese peers. Tobacco use showed no significant associations. These findings suggest that sleep-related behaviors, sports participation, and, to a lesser extent, BMI, are relevant correlates of academic progress, supporting university health policies addressing sleep, physical activity, and nutrition.