Rationale: The aim of this study was to examine the prevalence and determinants of PA, sedentary behaviors, and BMI among female university students in south western KSA.

Methods: This cross-sectional study included 663 female students who were randomly selected from a female university centre. Logistic regressions were used to identify determinants for moderate and vigorous PA, sedentary behaviors, and overweight/obesity and underweight.

Results: The females reported moderate PA in 49% and vigorous PA in 21% of cases, as defined by the American College of Sports Medicine recommendations. Total energy expenditure in METs-min/week increased with increased BMI (1216 among underweight, 1474 among normal weight, and 1810 among overweight). Sedentary behaviors were found among 15% of participants. The prevalence of overweight and obesity was 24%, and underweight 19%. Significant predictors for moderate PA were found to be present of one obese parent (negative relation), proximity to parks, and BMI (positive relation) while vigorous PA was predicted by age, fathers' level of education, waist-height ratio (negative relation), mothers' level of education, proximity to molls and parks, and BMI (positive relation). Sedentary behaviours were only predicted by proximity to parks. Overweight and obesity were found to correlate to the number of sisters (negative relation), presence of one obese parent, obese siblings, and proximity to molls (positive relation). On the other hand, both age and presence of obese parents were found to be negatively and significantly correlated to underweight.

Conclusion: A minority of the subjects met with current recommendations for PA. Intervention studies and implementation of national nutritional and PA guidelines are needed and should be integrated in the education of the adolescents and young adults.