High-Intensity Circuit Training Plus Sleep Health Intervention for Sleep Improvement: A Randomized Clinical Trial.

IMPORTANCE: Exercise training and sleep intervention can improve sleep; however, whether these interventions have a synergistic effect on improving sleep and cardiometabolic health is unknown. OBJECTIVE: To investigate individual and synergistic effects of a combined high-intensity circuit training (HICT) and sleep health (SH) intervention, compared with HICT alone, SH alone, and a control group, on objective and subjective sleep outcomes and cardiometabolic health. DESIGN, SETTING, AND PARTICIPANTS: This single-blind, parallel, 4-arm randomized clinical trial was conducted between July and September 2024. Participants were sedentary women of Chinese nationality aged 18 to 30 years with poor sleep health at baseline (total Pittsburgh Sleep Quality Index [PSQI] score >5). INTERVENTIONS: The interventions were administered for 8 weeks. The HICT intervention was performed in a laboratory and included 3 high-intensity body weight training sessions per week. The SH protocol was provided by trained research staff in both a laboratory and online and included individualized sleep counseling followed by the delivery of information extracted from a digital, smartphone-based app for cognitive behavioral therapy for insomnia and weekly visits. Control group participants followed their original lifestyle. MAIN OUTCOMES AND MEASURES: Subjective sleep outcomes, assessed by the PSQI, and objective sleep outcomes, assessed using actigraphy. Secondary outcomes included cardiometabolic health markers such as cholesterol and adiponectin levels. RESULTS: In total, 112 women (mean [SD] age, 23.5 [3.2] years) participated in the study. In the postintervention test, compared with the groups receiving either HICT or SH alone, the combined HICT-SH group had greater improvements in sleep efficiency (difference between HICT-SH and SH: 2.75 [95% CI, 0.65-4.85] percentage points; P = .004), reductions in wake after sleep onset (difference between HICT-SH and HICT, 14.51 [95% CI, 3.76-25.27] minutes [P = .002]; between HICT-SH and SH, 16.26 [95% CI, 5.50-27.01] minutes [P < .001]), and reduced activity counts during sleep (difference between HICT-SH and SH, 7980 [95% CI, 2026-13 934]; P = .003). Compared with the control group, all 3 intervention groups showed improvements in sleep efficiency, latency, wake after sleep onset, activity counts, sleep duration, and total PSQI score. CONCLUSIONS AND RELEVANCE: In this randomized clinical trial, synergistic effects of a combined HICT and SH intervention improved objective and subjective sleep outcomes and cardiometabolic health more than each intervention individually. These findings may guide treatment and primary prevention of sleep disorders. TRIAL REGISTRATION: Chinese Clinical Trial Registry: ChiCTR2400086853.