Sleeping approximately 7 hours and 18 minutes per night may be the most beneficial duration for reducing the risk of insulin resistance — a condition considered a precursor to type 2 diabetes. This conclusion was reached by researchers who analyzed data from a large observational study. The findings were published in BMJ Open Diabetes Research & Care.

The analysis included 23,475 adults aged 20 to 80 who participated in the U.S. National Health and Nutrition Examination Survey (NHANES) between 2009 and 2023. Scientists compared sleep duration with the eGDR index, a calculated indicator of insulin sensitivity. The lower the score, the higher the risk of insulin resistance.

The results revealed a U-shaped relationship between sleep duration and metabolic health. The most favorable eGDR levels were observed among individuals who slept about 7 hours and 18 minutes per night. Among those who slept less, increasing sleep duration was associated with improved metabolic indicators. However, when sleep exceeded this amount, additional hours were linked to a higher risk of impaired glucose metabolism — particularly among women and individuals aged 40 to 59.

The study also found that “catch-up sleep” on weekends may have varying effects. For people who are sleep-deprived during the week, an extra one to two hours of sleep on weekends was associated with better metabolic outcomes. In contrast, for those who already get sufficient or longer-than-recommended sleep, more than two additional hours were associated with worsened glucose metabolism indicators.

Previous research has also shown that regularly listening to music may improve sleep quality in older adults.