A cross-sectional analysis using NHANES data examined the relationship between sleep duration and estimated glucose disposal rate (eGDR), a proxy for insulin sensitivity that integrates factors such as HbA1c, blood pressure, and waist circumference. The study included 23,475 adults after excluding pregnant individuals and those under 20. Weekday sleep duration showed a non-linear, inverted U-shaped association with eGDR, with a turning point at about 7 hours 19 minutes (7.32 hours). Within this framework, longer weekday sleep up to 7.32 hours correlated with higher eGDR (lower insulin resistance), while sleep of 7.32 hours or more associated with lower eGDR. Subgroup analyses indicated the strongest adverse association at or above 7.32 hours among women, adults aged 40–59, and individuals with BMI ≥30. Weekend catch-up sleep modified the weekday relationship: among those sleeping <7.32 hours on weekdays, adding up to 2 hours on weekends related to higher eGDR, especially when the gain was 1–2 hours. For those already achieving ≥7.32 hours, weekend catch-up sleep showed no clear eGDR benefit, and excess weekend sleep could attenuate glycemic control.
Experts are interested in finding the optimal amount of sleep for different aspects of health. One area of interest is how sleep relates to metabolic syndrome , a cluster of conditions that increase risk for serious diseases like coronary heart disease.
One recent study explored how sleep duration relates to insulin sensitivity, which can be a driving factor for type 2 diabetes.
The authors of this study explain that in metabolic syndrome, the body is less responsive to insulin.
The study, published in BMJ Open Diabetes Research & Care , found that a little less than seven and a half hours of sleep is linked to the best level of insulin sensitivity.
Moreover, for people who got less sleep than this amount, getting over one and up to two hours more sleep on the weekend appeared to help insulin sensitivity the most.
For this cross-sectional study, researchers gathered their data from the National Health and Nutrition Examination Survey .
They looked at how sleep was related to estimated glucose disposal rate. This measurement takes into account hemoglobin A1C, high blood pressure, and waist circumference, which also reflects insulin resistance. An increased estimated glucose disposal rate (eGDR) would indicate less insulin resistance.
Researchers excluded certain individuals, such as pregnant participants and individuals younger than age 20, ultimately including 23,475 participants in their analysis. They had access to participants’ answers to how much they typically slept on weekdays. For about 11,000 participants, they also had data on about how many hours participants slept on weekends.
They then broke down the amounts of weekend catch-up sleep into four categories, ranging from no weekend catch-up sleep to more than two hours of weekend catch-up sleep.
Seven and a half hours of sleep was the median for sleep during the week, while eight hours was the median over the weekend.
Researchers identified a non-linear relationship between weekday sleep and eGDR, specifically an inverted U-shape. They estimated the turning point to be about 7 hours and 19 minutes of sleep, or 7.32 hours. Up to this amount, getting more sleep was linked to higher eGDR. But once people slept 7 hours and 19 minutes or more, getting even more sleep was linked to lower eGDR.
When they looked at different groups separately, the results were mostly the same. The connection between sleeping 7 hours and 19 minutes or more and having lower eGDR was especially strong for women, adults aged 40 to 59, and people with a body mass index (BMI) of 30 or higher.
Next, researchers looked at how weekend catch-up sleep came into play. They found that for people with sleep duration of less than 7.32 hours, getting up to two hours of extra sleep on the weekend was linked to increased eGDR levels.
The greatest benefit was seen in participants who were in the more than one hour and up to two hours of extra sleep group. For participants who were getting at least 7.32 hours or more, weekend catch-up sleep didn’t have a significant link to eGDR.
Further analysis revealed that getting more than two hours of weekend catch-up sleep moderated the negative link between the amount of sleep during the week and eGDR, compared to no weekend catch-up sleep. This suggests that getting higher amounts of weekend catch-up sleep could ultimately worsen blood sugar control.
With additional analysis, the authors suggest that getting excessive amounts of weekend catch-up may not be “recommended for optimal health outcomes.” They did find that for people getting less than 7.32 hours of sleep, the ideal amount of weekend catch-up sleep was 1.16 hours, and for people getting at least 7.32 hours, the amount was 1.12 hours.
David Cutler , MD, board certified family medicine physician at Providence Saint John’s Health Center in Santa Monica, CA, who was not involved in the study, noted that the study showed that getting enough sleep during the week was important for health.
“[An] interesting aspect of this study’s findings was that while 7.32 hours was found to be the ideal sleep duration, getting weekend catch-up sleep when a sleep debt occurred, was only beneficial in moderation, not when it exceeded two hours. The take-home message seems to be to get 7 – 8 hours’ sleep per night and only use the weekends to make up for 2 hours of lost sleep during the week.” — David Cutler, MD