Miller School of Medicine Experts Highlight Synergistic Power of Sleep and Exercise in Improving Health
Summary
- A new commentary by University of Miami Miller School of Medicine researchers underscores that pairing sleep and exercise interventions may produce health benefits greater than either strategy alone.
- The commentary looks at a study led by Dr. Borui Zhang that showed how improving sleep continuity and increasing high‑intensity exercise can jointly strengthen cardiometabolic health.
- Drs. Seixas, Jean‑Louis and Chung suggest that the real promise of such combined interventions may extend beyond cardiometabolic health. The authors point toward dementia prevention, noting that their own, ongoing trial is examining these synergistic effects on brain aging.
A new commentary by University of Miami Miller School of Medicine researchers Azizi Seixas, Ph.D., Girardin Jean‑Louis, Ph.D., and Debbie Chung, Ph.D., underscores a growing body of evidence that pairing sleep and exercise interventions may produce health benefits greater than either strategy alone.
Their invited analysis, published in JAMA Network Open, examines a recent, randomized clinical trial and clarifies why the findings represent a meaningful shift in behavioral medicine.
Dr. Seixas is an associate professor of psychiatry and behavioral sciences, director of The Media and Innovation Lab, associate director of the Center for Translational Sleep and Circadian Sciences and interim chair of the Department of Informatics and Health Data Science at the Miller School. Dr. Jean‑Louis is a professor of psychiatry and behavioral sciences and neurology and director of the Center for Translational Sleep and Circadian Sciences at the Miller School. Dr. Chung is a research assistant professor of psychiatry and behavioral sciences at the Miller School.
Beyond “Sleep and Exercise Are Good”
In their commentary, Dr. Seixas, Dr. Jean-Louis and Dr. Chung emphasize that, while sleep and physical activity have long been recognized as essential for health, most research has studied them in isolation. What makes the object of their commentary, the Zhang trial, important is its demonstration of the idea that targeting both behaviors simultaneously yields benefits that exceed the sum of their parts.
The Miller School trio notes the trial shows how improving sleep continuity and increasing high‑intensity exercise can jointly strengthen cardiometabolic health. The finding aligns with large, observational studies but has seldom been proven in controlled experiments. By quantifying these combined effects, Dr. Zhang’s study supports more precise behavioral models and frameworks that may guide personalized interventions based on individual risk profiles.
Study Summary: How the Zhang Trial Was Conducted
Dr. Zhang and colleagues conducted an eight‑week, single‑center randomized clinical trial involving sedentary women between the ages of 18 and 30 with poor sleep quality, defined by a Pittsburgh Sleep Quality Index score above five. Participants were assigned to one of four groups:
• High‑intensity circuit training (HICT)
• Digital sleep health intervention using cognitive behavioral therapy for insomnia
• Combined HICT and sleep intervention
• Usual lifestyle control
The research team measured both subjective and objective sleep using wrist actigraphy and validated questionnaires such as the Insomnia Severity Index and Epworth Sleepiness Scale. They also evaluated a broad set of metabolic biomarkers, including glucose, insulin, lipids, adiponectin and high‑sensitivity C‑reactive protein.
Key Findings: Combined Interventions Deliver Superior Gains
Drs. Seixas, Jean‑Louis and Chung highlight that the combined sleep and exercise intervention produced the greatest improvements, including:
• Higher sleep efficiency
• Reduced wake time after sleep onset
• Lower nocturnal activity counts
• Favorable shifts in lipid profiles and adiponectin
• Decreases in waist circumference
These changes exceeded the effects of exercise or sleep interventions alone, providing what the authors call the “strongest experimental evidence to date” that sleep and physical activity reinforce each other to improve health.
The Specifics of Sleep and Exercise
The commentary places the Zhang study within a larger scientific context. Drs. Seixas, Jean‑Louis and Chung explain that poor sleep and inactivity jointly increase allostatic load, reflecting stress on physiological systems involved in metabolic, inflammatory and neurobiological function.
In contrast, better sleep and regular exercise normalize cardiometabolic profiles, reduce inflammation, synchronize circadian rhythms and support brain processes.
Their interpretation suggests that the real promise of such combined interventions may extend beyond cardiometabolic health. The authors point toward dementia prevention as a major frontier, noting that their own, ongoing trial is examining these synergistic effects on brain aging.
Limitations and Future Directions
The commentary also urges caution and outlines key gaps:
• The trial included only young adult women, limiting generalizability.
• Measurements were taken only at baseline and eight weeks, preventing analysis of change over time.
• Critical biomarkers such as cortisol, melatonin phase or inflammatory cytokines were not collected.
• Durability of the intervention’s effects remains unknown.
Drs. Seixas, Jean‑Louis and Chung recommend broader participant diversity, longer follow‑ups, continuous wearable monitoring and mechanistic biomarker analysis in future studies. Such work, they argue, is necessary to advance precision behavioral medicine, where tailored combinations of sleep and activity interventions are matched to individuals based on need and biological response.
As the researchers emphasize, the Zhang study provides a crucial springboard for designing future interventions that leverage the synergy between sleep and exercise, an approach that may benefit cardiometabolic health today and cognitive health tomorrow.
Tags: Department of Informatics and Health Data Science, Department of Psychiatry and Behavioral Sciences, digital health, Dr. Azizi Seixas, Dr. Debbie Chung, Dr. Girardin Jean-Louis, Media and Innovation Lab, physical fitness, sleep, sleep disorders, sleep patterns, Translational Sleep and Circadian Sciences