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Evening high-intensity interval training (HIIT) and moderate-intensity interval training (MIIT) produce similar acute changes in circadian core body temperature mesor and phase in adults with obesity, with a borderline non-significant difference in amplitude change.

In a randomized crossover trial of 9 adult males with obesity, evening HIIT (~30 min at 90% HRR) and MIIT (~50 min at 60% HRR) both produced approximately one-hour phase advances in circadian core body temperature rhythm. The change in circadian temperature amplitude differed in direction between conditions (MIIT -0.01 ± 0.19 °C; HIIT +0.12 ± 0.24 °C) but did not reach statistical significance (p = 0.060, d_z = 0.73).

Last updated: Jul 15, 2026•1 RCTs•📖 Read as article →

Evidence Score

Evidence Score44/100
Human RCT★★☆☆☆
Meta-analysis☆☆☆☆☆
Mechanism★★★★★
Safety★★★★☆
Confidencelow

Study Evidence

Study 1. Effects of exercise intensity on circadian rhythm and glucose regulation in adults with obesity: a randomized crossover trial.

observational

Kim YI, Lee J, Cho S, In J, Seo M, Lee J, Choi Y, Park J · Physical activity and nutrition (2026)

Participants: N/A
Duration: 24 hours post-exercise
Intervention: Evening high-intensity interval training (HIIT, ~30 min at 90% heart rate reserve) versus moderate-intensity interval training (MIIT, ~50 min at 60% heart rate reserve) on a cycle ergometer between 19:00 and 21:00
Outcome: Change in circadian core body temperature amplitude, mesor, acrophase; 24-hour glucose regulation (mean glucose, coefficient of variation, time in range, mean amplitude of glycaemic excursions); sleep quality (sleep efficiency, total sleep time, wake after sleep onset)
Effect Size: d_z = 0.73 for amplitude change between conditions
Population: Nine adult males with obesity (BMI ≥ 25 kg/m², Asia-Pacific criterion)

Result:

PubMed: 42438852DOI: 10.20463/pan.2026.0029

Mechanism Graph

Evening exercise acts as a non-photic zeitgeber
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Exercise intensity may differentially affect core body temperature regulation
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Temperature amplitude changes reflect circadian rhythm adjustment
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Result: HIIT and MIIT produce similar phase advances but potentially different amplitude changes

Limitations

  • ⚠Small sample size (n=9) limits statistical power and generalizability
  • ⚠Single-session acute design does not assess chronic effects of repeated exercise
  • ⚠Only males were studied, limiting applicability to females with obesity

Frequently Asked Questions

Does evening exercise disrupt sleep in people with obesity?▼

In this study, neither HIIT nor MIIT significantly affected sleep efficiency, total sleep time, or wake after sleep onset compared to baseline, suggesting evening exercise at these intensities does not impair sleep.

Which exercise intensity is better for glucose regulation in obesity?▼

Twenty-four-hour mean glucose trended lower after MIIT (95.9 mg/dL) than HIIT (98.7 mg/dL), but the difference was not statistically significant (p = 0.081). Glucose variability did not differ between conditions.

Can evening exercise shift circadian rhythms in people with obesity?▼

Yes, both HIIT and MIIT produced approximately one-hour phase advances in core body temperature rhythm, indicating that evening exercise can act as a zeitgeber in adults with obesity.

What was the main finding of this study?▼

The study found that evening HIIT and MIIT produced similar acute changes in circadian mesor and phase, with a borderline non-significant difference in amplitude change favoring HIIT. No significant differences were observed in glucose regulation or sleep quality.

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References

  1. 1.Kim YI, Lee J, Cho S, In J, Seo M, Lee J, Choi Y, Park J. "Effects of exercise intensity on circadian rhythm and glucose regulation in adults with obesity: a randomized crossover trial.." Physical activity and nutrition, 2026. PMID: 42438852 DOI: 10.20463/pan.2026.0029
Disclaimer: This content is for educational purposes only and is not medical advice. Evidence scores reflect the quality and quantity of available research, not clinical recommendations. Always consult a healthcare professional before starting any supplement or intervention.