The Study
0140 Extending Overnight Fasting to Improve Cardiometabolic Health in Middle Age and Older Adults
This study gave some people a new eating schedule and compared them to others who ate the same as before. It found that the new schedule helped their body handle sugar better and lowered their heart rate and blood pressure at night. But it doesn't prove that fasting will make everyone healthier—it just shows what happened in this small group.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
People who stopped eating 3 hours earlier at night for six weeks had better blood sugar control and healthier heart rhythms while sleeping — even though they ate the same amount and slept the same amount.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 547 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — better blood sugar control and nighttime heart/blood pressure patterns suggest lower risk for diabetes and heart disease, even without losing weight or changing sleep.
- 2Blood sugar dropped significantly (p<0.0001), heart rhythm improved (p<0.0006), and nighttime blood pressure and heart rate dipped more (p=0.042 and p=0.028).
- 3Sleep didn't change.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
SLEEP
Year
2025
Authors
Daniela Grimaldi, K. Reid, Sabra M Abbott, Kristen Knutson, Phyllis C. Zee
Related Content
Claims (6)
Fasting for 12 to 16 hours is associated with higher heart rate variability and lower resting heart rate, while fasting for more than 48 hours is associated with lower heart rate variability.
In middle-aged and older adults with obesity and normal blood sugar, extending overnight fasting to 12–16 hours for six weeks lowers blood glucose levels and increases insulin secretion in response to glucose during a glucose tolerance test.
In middle-aged and older adults, fasting overnight for 12 to 16 hours for six weeks reduces the low-frequency to high-frequency ratio in heart rate variability, reflecting a shift toward greater parasympathetic and lower sympathetic nervous system activity during sleep.
In middle-aged and older adults with normal-to-prediabetic blood sugar, extending overnight fasting by three hours for six weeks does not change sleep patterns.
In middle-aged and older adults with normal-to-prediabetic blood sugar, delaying nighttime eating by three hours for six weeks improves blood sugar control, heart rate regulation during sleep, and nighttime blood pressure drop, without changing how much they eat or how they sleep.
In middle-aged and older adults, fasting for 12 to 16 hours overnight for six weeks increases the normal drop in diastolic blood pressure and heart rate during sleep, reflecting stronger circadian control of cardiovascular activity at night.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.