The moderating effect of physical activity in the relationship between sleep quality and BMI in adults with overweight and obesity

Inadequate sleep quality is a significant risk factor for overweight and obesity, which in turn may predispose individuals to adverse health outcomes. The aim of the present study was to evaluate the moderating effect of physical activity on the relationship between sleep quality and BMI in adults with overweight and obesity. In the current cross-sectional study, 589 white European participants (mean age 50 ± 12.2 years; 65% women; mean BMI 31.4 ± 5.5 kg/m²) were recruited from the International Center for the Assessment of Nutritional Status in Italy between October 2021 and July 2022. They completed the Godin-Shephard Leisure Time Physical Activity Questionnaire and the Pittsburgh Sleep Quality Index. The significant moderation model analysis performed on the entire sample [<i>F</i>(_{3, 585}) = 4.4, <i>p</i> = 0.0045, <i>r</i> = 0.15, <i>r</i> ² = 0.02] found a statistically significant association between sleep quality and BMI (<i>β</i> = -0.16, <i>p</i> = 0.05), between physical activity and BMI (<i>β</i> = -0.08, <i>p</i> = 0.0018), and between the interaction of sleep quality and physical activity and BMI (<i>β</i> = 0.01, <i>p</i> = 0.01), particularly for physical activity values equal or higher than 49 Leisure Score Index (<i>p</i> = 0.004). The moderation analysis revealed a significant effect of physical activity on the relationship between sleep quality and BMI; better sleep quality was associated with lower BMI in individuals with higher levels of physical activity. The present findings suggest new aspects relating to the effect of physical activity in the relationship between sleep quality and overweight/obesity. Therefore, focusing on maintaining adequate levels of physical activity may represent an effective complementary strategy.