The Relationship between Sleep Quality and Body Composition among Male Novice Sri Lankan Bodybuilders Aged 18–21 Years in the Kandy District

Introduction: Sleep is relevant to recovery and physical performance but evidence on its association with changes in body composition among novice bodybuilders in Sri Lanka is limited. Poor sleep quality has reached epidemic levels, especially among young adults, adversely affecting metabolic, cognitive, and physical health. Aims: To assess the association between sleep quality and changes in body composition among male novice bodybuilders aged 18–21 years in Kandy District, Sri Lanka. Study Design: A quantitative observational cohort study. Study Setting and Duration: Selected training centres in Kandy District, Sri Lanka; data collection took place over eight weeks of standardised training. Methodology: A standardised resistance-training regimen was completed by 50 novice bodybuilders aged 18–21 years. Sleep quality was assessed at baseline using the Pittsburgh Sleep Quality Index (PSQI). Body weight and body-composition estimates were measured at baseline and week 8 using bioelectrical impedance analysis (BIA) and the skinfold caliper method. Results: PSQI scores were moderately correlated with both baseline body-fat percentage (r =.45, P =.001) and change in body-fat percentage (r =.38, P =.006), with participants with poorer sleep showing smaller reductions over time and higher baseline body fat. PSQI scores were moderately negatively correlated with changes in lean body mass (r = −.41, P =.003) and skeletal muscle mass (r = −.54, P <.001). Participants with good sleep quality gained more BIA-estimated skeletal muscle mass (1.07 ± 0.48 kg) than those who slept poorly (0.61 ± 0.48 kg; P =.007). Sleep quality accounted for 29.2% of the variation in skeletal muscle mass change. These findings supported the rejection of the null hypotheses: poorer sleep quality was associated with higher body fat and smaller gains in lean mass. Conclusion: In this sample, poorer baseline self-reported sleep quality was associated with less favourable body-composition changes over eight weeks. Larger studies using objective sleep measures, clearly specified body-composition methods, and adjustment for relevant confounders are needed.