The Effects of High-Intensity Interval Training (HIIT) on Sleep Quality in Obese Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background: Obesity adversely affects sleep quality through mechanisms such as obstructive sleep apnea (OSA) and hormonal imbalances that disrupt the circadian rhythm. High-intensity interval training (HIIT) helps reduce fat, inflammation, and stress, which in turn leads to improvements in deep and restful sleep. Method: This study aimed to examine the effects of HIIT on sleep quality in obese patients through a systematic review and meta-analysis of studies published in five databases: PubMed, Scopus, Ovid, The Cochrane Library, and Google Scholar. Randomized controlled trials (RCTs) comparing obese patients undergoing HIIT with control groups and assessing sleep quality via subjective measures such as the Pittsburgh Sleep Quality Index (PSQI) and objective assessments were included. Result: Eight eligible studies were identified, with six included in the meta-analysis, comprising a total of 191 participants. The analysis revealed that HIIT significantly improved overall sleep quality, as evidenced by a reduction in PSQI scores (mean difference, −3.51; 95% CI (−4.78, −2.25); p < 0.001). Significant improvements were also observed in PSQI subscales, including sleep duration (mean difference, −0.42; 95% CI (−0.58, −0.26); p < 0.001), habitual sleep efficiency (mean difference, −0.32; 95% CI (−0.59, −0.05); p = 0.02), and daytime dysfunction (mean difference, −0.66; 95% CI (−1.27, −0.05); p = 0.03). Moreover, HIIT led to a notable reduction in OSA severity, as reflected by lower Apnea–Hypopnea Index (AHI) scores (mean difference, −28.31, 95% CI (−34.39, −22.22); p < 0.001). Conclusion: HIIT significantly improves sleep quality in obese patients and reduces the severity of obstructive sleep apnea. Further long-term studies with improved control of confounding factors are recommended to validate and strengthen these findings.