A recent study conducted by the Westlake Laboratory of Life Sciences and Biomedicine in China has uncovered a significant link between sleep duration, sleep onset timing, and glycemic variability in adults. By analyzing continuous glucose monitoring (CGM) data, researchers found that individuals with persistent short sleep and late bedtimes exhibited greater fluctuations in blood glucose levels. These findings add to growing evidence that sleep patterns play a critical role in metabolic health, with potential implications for diabetes prevention and management.
Glucose regulation is fundamental to overall metabolic function, and excessive fluctuations in blood sugar levels have been linked to an increased risk of diabetes complications, including cardiovascular disease, nerve damage, and kidney dysfunction. While previous studies have identified insufficient sleep as a risk factor for impaired glucose metabolism, little research has explored the long-term effects of sleep duration and bedtime habits on glycemic variability. This study aimed to fill that knowledge gap by tracking multi-year sleep patterns and their impact on blood sugar regulation.
The study, titled “Trajectories of Sleep Duration, Sleep Onset Timing, and Continuous Glucose Monitoring in Adults,” was published in JAMA Network Open and utilized a prospective cohort study design. The researchers examined 1,156 participants aged 46 to 83 from the Guangzhou Nutrition and Health Study, a long-term, community-based cohort in Guangdong, China. Participants self-reported their sleep patterns over multiple visits, providing detailed data on their sleep duration and bedtime habits. In addition, they wore CGM devices for 14 consecutive days, allowing researchers to monitor real-time fluctuations in blood glucose levels with high precision.
Through their analysis, the researchers identified four distinct sleep duration trajectories:
- Severe inadequate sleep: 4.7 to 4.1 hours per night
- Moderate inadequate sleep: 6.0 to 5.5 hours per night
- Mild inadequate sleep: 7.2 to 6.8 hours per night
- Adequate sleep: 8.4 to 8.0 hours per night
They also classified participants into two distinct sleep onset timing groups:
- Persistent early sleep onset
- Persistent late sleep onset
When analyzing the CGM data, researchers observed a clear association between sleep patterns and glycemic variability. Those in the severe inadequate sleep group showed a 2.87% increase in glycemic variability (as measured by the coefficient of variation, CV) and a 0.06 mmol/L increase in mean daily glucose fluctuations (MODD) when compared to individuals in the adequate sleep group.
Participants in the late sleep onset group also exhibited a 1.18% higher glycemic variability and a 0.02 mmol/L increase in MODD, indicating that delayed bedtimes independently contribute to glucose instability. Notably, those who experienced both short sleep duration and late sleep onset showed the greatest glycemic variability, suggesting a compounded negative effect on blood sugar regulation.
The study’s findings reinforce the idea that long-term inadequate sleep duration and delayed bedtimes contribute to metabolic dysregulation. The body’s ability to regulate blood glucose effectively is heavily influenced by circadian rhythms, which control hormonal secretion, insulin sensitivity, and metabolic efficiency. Disruptions to sleep patterns—whether due to chronic sleep deprivation or a misaligned biological clock—may lead to poor glucose control and increase the risk of type 2 diabetes over time.
These results have significant clinical implications, particularly for individuals at risk of diabetes or those already managing the condition. Maintaining sufficient sleep duration and establishing earlier bedtimes could serve as an effective, non-pharmacological intervention for improving glycemic control. Healthcare providers may consider integrating sleep assessments into diabetes management plans, alongside traditional lifestyle interventions such as dietary modifications and physical activity.
Given the study’s observational nature, further research is needed to determine the mechanistic pathways linking sleep deprivation and glycemic variability. Future studies could also explore interventions aimed at improving sleep hygiene and whether they lead to long-term improvements in glucose regulation.
More information: Luqi Shen et al, Trajectories of Sleep Duration, Sleep Onset Timing, and Continuous Glucose Monitoring in Adults, JAMA Network Open (2025). DOI: 10.1001/jamanetworkopen.2025.0114