New research published in the journal Cardiovascular and Metabolic Risk indicates that sleeping slightly longer on weekends may benefit people who do not get enough sleep during the workweek, but adding extra hours when already sleeping sufficiently could negatively affect metabolic health.
The study investigated the association between weekday sleep duration and insulin sensitivity, using a measure called estimated glucose disposal rate (eGDR). This metric, calculated from waist circumference, hypertension, and glycated hemoglobin levels, is considered a general predictor of insulin resistance and mortality risk associated with metabolic syndrome. Previous studies have validated eGDR as a marker linked to long-term mortality risk in both elderly individuals and those without diabetes.
Researchers analyzed data from 23,475 participants collected through the National Health and Nutrition Examination Survey (2009-2023). They assessed self-reported weekday sleep duration and categorized weekend catch-up sleep (WCS) into four groups: none, up to one hour, between one and two hours, and over two hours. Weekend sleep data were available for 10,817 participants.
The median reported weekday sleep was 7.5 hours, rising to eight hours on weekends. About 48% of participants reported some degree of WCS. The analysis revealed an inverted U-shaped relationship between weekday sleep duration and eGDR. Each additional hour of weekday sleep below 7.32 hours was linked to improved insulin sensitivity (a 0.273-unit increase in eGDR), while more than 7.32 hours correlated with decreased insulin sensitivity (a 0.222-unit decrease per hour).
Moderate WCS—up to two hours—was associated with higher eGDR among those sleeping less than 7.32 hours on weekdays compared with no catch-up sleep. However, for individuals already getting at least 7.32 hours of weekday rest, WCS did not provide any benefit; instead, it was associated with lower eGDR.
Subgroup analyses indicated similar patterns among people with excess body weight or diabetes: increasing weekday sleep improved eGDR up to the threshold but declined beyond it. Among women and adults aged 40 to 59 years who slept at least 7.32 hours per night during the week, longer durations were also linked to lower eGDR.
Further modeling suggested that optimal eGDR values occurred with about one hour of weekend catch-up sleep for both groups above or below the threshold of sufficient weekly rest; however, these estimates are exploratory.
Physiological explanations include effects of restricted or excessive sleep on hormones such as leptin and ghrelin; changes in sympathetic activity; disruptions in circadian rhythms; increased inflammation; altered appetite regulation; reduced energy expenditure; or underlying conditions like depression.
The authors note several limitations: cross-sectional design limits causal conclusions; reliance on self-reported data may introduce recall bias; residual confounding from unmeasured lifestyle factors is possible; daytime napping was not distinguished from nighttime sleep.
"This is the first study to investigate the link between weekday sleep duration and the eGDR, as well as the moderating role of WCS on this association," according to the authors. "Here, they showed that weekday sleep duration was positively correlated with eGDR up to 7.32 hours, after which it showed a negative association."
"While 1–2 hours of WCS improved eGDR, this was only true with weekday sleep <7.32 hours," they stated further."Above this duration, WCS was associated with poorer metabolic markers, though these findings remain observational and correlational."
The study suggests prioritizing adequate regular nightly rest rather than relying on extended weekend recovery periods for better metabolic outcomes but calls for further research using objective measurements.
