Analysis of sleep quality and its impact on body composition on the pre-competition day in natural bodybuilders

Introduction: Bodybuilding is a sport that evaluates athletes based on their muscle mass, symmetry, and muscle definition, unlike conventional sports that are usually based on athletic performance in competition. Objective: The objective of the study was to determine the relationship between fat mass (FM) and skeletal muscle mass (SMM) through bioimpedance with sleep quality in Chilean natural bodybuilders on pre-competition day. Methodology: Twenty-six natural bodybuilders participated in the WNBF Chilean championship. The objective was to evaluate body composition to obtain data regarding SMM and FM. Additionally, the PSQI was applied. Results: significant relationships were obtained with SMM and PSQI (p= 0, 02, R = -0,38, R²= 0.14) and a moderate correlation between FM and PSQI (p= 0.04, R = 0.40, R²= 0.15). Sleep efficiency showed a negative correlation (p= 0.001, R = -0.55, R²= 0.31) with FM and a positive correlation (p = 0.002, R = 0.58, R²= 0.34) with SMM. Sleep duration showed a negative correlation (p = 0.024, R = -0.39, R²= 0.15) with FM and a positive correlation (p = 0.021, R = 0.45, R²= 0.20) with SMM. Discussion: A lack of sufficient sleep has been linked to adverse effects on body composition, including reduced fat loss and muscle gain. Additionally, insufficient sleep has been associated with a decline in athletic performance. Conclusions: The findings of this study indicate that poor sleep quality is associated with higher body fat and better sleep quality with an higher skeletal muscle mass, underscoring the significance of sleep for achieving optimal body composition and performance in natural bodybuilders.