Highlights
A randomized clinical trial involving sedentary young women demonstrated that a combined approach of High-Intensity Circuit Training (HICT) and Sleep Health (SH) interventions yields superior improvements in sleep efficiency compared to either intervention alone.
The synergistic effect of the combined intervention significantly reduced wake after sleep onset (WASO) by approximately 14 to 16 minutes more than monotherapy groups.
Beyond sleep quality, the combined HICT-SH protocol led to enhanced cardiometabolic health markers, including improved adiponectin levels and cholesterol profiles.
Findings suggest that integrated lifestyle interventions are more effective for the primary prevention of sleep disorders and metabolic dysfunction than isolated physical or behavioral strategies.
Background: The Sleep-Metabolism Nexus
Sleep health and physical activity are two pillars of metabolic and psychological well-being. Poor sleep quality—characterized by low efficiency, prolonged latency, and frequent nighttime awakenings—is increasingly recognized as a significant risk factor for obesity, type 2 diabetes, and cardiovascular disease. Conversely, sedentary behavior exacerbates sleep disturbances, creating a deleterious cycle that undermines long-term health.
While High-Intensity Circuit Training (HICT) has been lauded for its efficiency in improving cardiovascular fitness and metabolic health, its specific impact on sleep architecture remains a subject of ongoing research. Similarly, behavioral sleep health (SH) interventions, often derived from cognitive behavioral therapy for insomnia (CBT-I), are the gold standard for improving sleep hygiene. However, the potential synergy between these two modalities—whether exercise can enhance the receptivity to sleep interventions or vice versa—has remained largely unexplored in clinical literature. This study aimed to fill that gap by investigating the individual and combined effects of HICT and SH on objective and subjective sleep outcomes.
Study Design and Methodology
The study was a single-blind, parallel, 4-arm randomized clinical trial conducted between July and September 2024. The researchers recruited 112 sedentary Chinese women aged 18 to 30 years who met the criteria for poor sleep health, defined as a Pittsburgh Sleep Quality Index (PSQI) score greater than 5.
Participant Stratification
Participants were randomly assigned to one of four groups:
- Combined HICT and Sleep Health (HICT-SH)
- HICT alone
- Sleep Health (SH) intervention alone
- Control group (maintaining original lifestyle)
Intervention Protocols
The interventions lasted for 8 weeks. The HICT intervention consisted of three laboratory-based sessions per week, focusing on high-intensity bodyweight movements designed to reach 80% to 90% of maximum heart rate. The SH intervention combined individualized counseling with a digital, smartphone-based app providing CBT-I principles and weekly check-ins with trained research staff. This dual-layered approach ensured both physiological and behavioral triggers for sleep improvement were addressed.
Outcome Measures
The primary outcomes were divided into subjective and objective measures. Subjective sleep was assessed via the PSQI, while objective metrics—including sleep efficiency, wake after sleep onset (WASO), and sleep duration—were captured using wrist-worn actigraphy. Secondary outcomes focused on cardiometabolic markers, specifically looking at lipid profiles and adiponectin, a protein hormone involved in regulating glucose levels and fatty acid breakdown.
Key Findings: Quantifying the Synergy
The results of the trial provided compelling evidence for the superiority of the combined intervention model. While all intervention groups showed improvement over the control group, the HICT-SH group demonstrated significant incremental gains.
Superiority in Sleep Efficiency and Continuity
Post-intervention data revealed that the HICT-SH group had significantly greater improvements in sleep efficiency. Specifically, the difference between the HICT-SH group and the SH-only group was 2.75 percentage points (95% CI, 0.65-4.85; P = .004). This suggests that the physiological fatigue and subsequent recovery phase induced by HICT may enhance the effectiveness of behavioral sleep strategies.
The reduction in Wake After Sleep Onset (WASO) was perhaps the most striking finding. The HICT-SH group reduced nighttime wakefulness by 14.51 minutes more than the HICT-only group (P = .002) and 16.26 minutes more than the SH-only group (P < .001). Furthermore, activity counts during sleep—a proxy for restlessness—were significantly lower in the combined group compared to the SH group (difference of 7980 counts; P = .003).
Cardiometabolic Improvements
The trial also observed a “health halo” effect regarding cardiometabolic markers. The combined group showed more pronounced improvements in cholesterol levels and adiponectin compared to the control and single-intervention groups. This suggests that the synergistic effect of exercise and sleep doesn’t just make for a better night’s rest; it fundamentally alters the metabolic environment, potentially reducing the long-term risk of metabolic syndrome.
Expert Commentary: Mechanistic Insights
The findings of this trial align with the emerging “bi-directional” theory of exercise and sleep. Mechanistically, HICT may improve sleep by increasing the homeostatic sleep drive through the depletion of energy stores and the accumulation of adenosine in the brain. When combined with a Sleep Health intervention that reduces cognitive arousal and improves sleep hygiene, the body is both physiologically prepared for sleep and behaviorally permitted to maintain it.
Clinicians should note that the study focused on young, sedentary women. While this demographic is at high risk for developing chronic sleep issues, further research is needed to determine if these synergistic effects hold true for older populations or those with diagnosed clinical insomnia. However, the use of a digital app for the SH intervention highlights the scalability of such programs in a modern healthcare setting.
One limitation of the study is its 8-week duration. While sufficient to see changes in sleep architecture and blood markers, long-term sustainability of these lifestyle changes remains to be seen. Additionally, the sedentary nature of the participants at baseline may have made them more sensitive to the interventions than a more active cohort might be.
Conclusion and Clinical Implications
In this randomized clinical trial, the combination of High-Intensity Circuit Training and a structured Sleep Health intervention proved more effective than either strategy used in isolation. The synergy between physical exertion and behavioral modification resulted in deeper, more continuous sleep and better metabolic health profiles.
For healthcare providers, these results suggest that a multi-modal approach should be the standard of care for patients reporting poor sleep. Rather than prescribing exercise or sleep hygiene alone, an integrated prescription that addresses both the body’s physiological need for activity and the mind’s need for structured rest may yield the best clinical outcomes. These findings provide a clear roadmap for the primary prevention of sleep disorders and the promotion of cardiometabolic resilience in young adults.
Funding and Clinical Registration
This study was registered with the Chinese Clinical Trial Registry (ChiCTR2400086853). The researchers reported no conflicts of interest relevant to the conduct of this study. Funding was provided by institutional grants supporting public health and sports science research.
References
Zhang B, Zheng C, Liao Q, Zhang H, Fang Y, Wang W, Song H, Lau EY, Tse AC, Lo SK, Sun F. High-Intensity Circuit Training Plus Sleep Health Intervention for Sleep Improvement: A Randomized Clinical Trial. JAMA Netw Open. 2026;9(2):e2556927. doi:10.1001/jamanetworkopen.2025.56927
Irish LA, Kline CE, Gunn HE, Buysse DJ, Hall MH. The role of sleep hygiene in promoting public health: A review of sleep hygiene practices and interventions. Sleep Med Rev. 2015;22:23-36.
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