Predicted Basal Metabolic Rate and Sleep Continuity in Chronic Insomnia Disorder: An Age- and Sex-Matched Cohort Study

Background and Objective Chronic insomnia disorder is characterized by physiologic hyperarousal, yet evidence regarding elevated basal metabolic rate (BMR) is inconsistent. Whether predicted BMR—an accessible, anthropometry-derived metabolic estimate—relates to objective sleep continuity is unclear. This study examined 1) whether predicted BMR differs between individuals with chronic insomnia and matched controls and 2) whether predicted BMR is associated with polysomnography (PSG) markers of sleep continuity.Methods Among 7,338 adults who underwent overnight PSG and bioelectrical impedance analysis from 2017–2024, 225 individuals with chronic insomnia disorder were identified using International Classification of Sleep Disorders, Third Edition criteria and age- and sex-matched to 225 controls. Predicted BMR was calculated using the Harris–Benedict equations. Group comparisons and correlation and partial correlation analyses assessed associations between predicted BMR and PSG-derived sleep variables.Results A total of 450 participants (mean age, 36.4±13.1 years; 57% female) were included. Predicted BMR did not differ between insomnia and control groups (1,409.5±257.3 vs. 1,426.0± 272.0 kcal/day, p=0.60). No significant associations were observed between predicted BMR and PSG metrics in controls. In the insomnia group, higher predicted BMR correlated with longer total sleep time (r=0.203), higher sleep efficiency (r=0.248), shorter sleep latency (r=-0.196), and reduced wake after sleep onset (r=-0.195), with all p≤0.003; associations partially persisted after adjustment for age and BMI.Conclusions Predicted BMR does not differentiate insomnia from matched controls but is selectively coupled with objective sleep continuity within the insomnia phenotype. Predicted BMR may reflect metabolic heterogeneity and physiologic correlates of sleep stability in chronic insomnia.