Sleep-Aligned Extended Overnight Fasting Improves Nighttime and Daytime Cardiometabolic Function.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 41674465 · doi:10.1161/ATVBAHA.125.323355
What was done
In a 7.5-week randomized parallel-arm controlled trial, 39 overweight or obese participants aged 36–75 years completed either an individualized extended overnight fasting intervention (13–16 hours of fasting with the final meal at least 3 hours before sleep) or a control condition maintaining habitual fasting patterns (11–13 hours). Both groups dimmed lights 3 hours before bedtime. Coprimary outcomes were nighttime dipping of diastolic blood pressure and insulin sensitivity assessed via the Matsuda Index; secondary outcomes included nighttime autonomic function and morning oral glucose tolerance.
What was found
The abstract reports directional outcomes without providing numerical values or confidence intervals. Compared with control, extended overnight fasting significantly improved the coprimary outcome of nighttime diastolic blood pressure dipping, but showed no significant effect on the coprimary Matsuda Index of insulin sensitivity. For secondary measures, the intervention resulted in lower nighttime heart rate, higher heart rate variability, lower nighttime cortisol, lower glucose levels during the oral glucose tolerance test, and a higher 30-minute insulinogenic index.
Why it matters
Extending overnight fasting in alignment with sleep schedules represents an accessible lifestyle strategy that can improve nocturnal cardiovascular autonomic function and acute morning glucose handling.
Limits
The sample size was small (n = 39) and limited to middle-aged and older overweight or obese individuals. The intervention duration was brief (7.5 weeks). The abstract omits exact numerical data, and the intervention failed to improve one of its two coprimary outcomes.
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