Short and irregular weekday sleep disrupts glucose regulation even after weekend sleep recovery, NUS Medicine study reveals

Published: 02 Dec 2025

Study lead Assistant Professor June Chi-Yan Lo, Principal Investigator at the Centre for Sleep and Cognition at NUS Medicine, and co-author Adjunct Associate Professor Khoo Chin Meng, from the Department of Medicine at NUS Medicine.

Researchers at the Yong Loo Lin School of Medicine, National University of Singapore (NUS Medicine), have found that insufficient weekday sleep significantly disrupts glucose metabolism even when weekend sleep is extended. Published in SLEEP, the study provides insights into the impact of recurrent sleep curtailment on the body’s ability to process glucose and type 2 diabetes mellitus risk.

The study, led by Assistant Professor June Chi-Yan Lo, Principal Investigator at the Centre for Sleep and Cognition, NUS Medicine, with co-author Adjunct Associate Professor Khoo Chin Meng, from the Department of Medicine at NUS Medicine, examined how consistent short sleep and irregular short sleep schedules affected the body’s ability to manage glucose. Over two weeks in a controlled environment in the sleep lab, 48 healthy young adults aged 21 to 35 years were assigned to sleep schedules that simulated “stable short sleep”, “variable short sleep”, or adequate “control” sleep on weekdays. An Oral Glucose Tolerance Test throughout the study to monitor glucose changes.

The stable short sleep group slept six hours on each weekday night and eight hours on each weekend night, mirroring a typical work or school week. The variable short sleep group also slept eight hours on weekend nights, but followed a fluctuating weekday schedule ranging from four to eight hours each night, with the same total duration of time in bed as the stable short sleep group. The control group was given eight hours to sleep each night during the entire study. All the meals were tailored to the participant’s individual caloric and macronutrient needs throughout the study.

Despite two nights of sufficient sleep on the weekends, both short sleep groups exhibited impaired glucose tolerance.
• For those who consistently slept six hours each weekday, signs of insulin resistance were observed. Their bodies produced more insulin in an attempt to stabilise blood sugar; however, their blood glucose levels remained elevated compared to that at a well-rested state.
• The group with variable short sleep experienced even more prominent increases in glucose concentrations. Crucially, they showed no significant compensatory insulin overproduction, suggesting possible early impairment of the pancreas’s insulin-producing cells.

These findings collectively indicate an increased risk of developing type 2 diabetes mellitus for short-sleeping individuals.

In contrast, the control group, which consistently had adequate sleep every night, showed no significant change in blood glucose levels throughout the study. These findings underscore the critical role of consistent, adequate sleep in glucose regulation. Furthermore, they suggest that weekday short sleep has a detrimental impact on our bodies’ ability to process glucose, increasing type 2 diabetes mellitus risk, even with catch-up sleep on weekends, and that the regularity of our weekday short sleep could affect the way this impairment develops, and possibly how severe it gets.

“Many people believe weekend sleep can ‘reset’ the body, but our findings show that weekend catch-up sleep may not be able to prevent increases in blood glucose levels induced by subsequent sleep curtailment on weekdays,” said Asst Prof Lo. “Our study findings suggest vital links between sleep duration as well as regularity, and type 2 diabetes mellitus risk. Understanding how sleep patterns affect glucose regulation can help us provide more holistic treatment plans.” Asst Prof Lo holds appointments at the Human Potential Translational Research Programme and the Department of Medicine, NUS Medicine.

Through this study, the researchers aim to guide both individuals and health professionals to understand the factors that contribute to type 2 diabetes mellitus risk, and consider adequate and regular sleep as a possible intervention component when addressing metabolic health conditions. Future research may focus on the sleep patterns in other demographics and patients with underlying risk factors for type 2 diabetes mellitus.