In the News

Researchers at Mass General Brigham have now uncovered evidence that daytime napping and daytime sleepiness should be considered related, although distinct, features of the impaired arousal continuum, and that habitual daytime napping has causal effects on cardiometabolic health.

Eating dinner close to bedtime when endogenous melatonin levels are high is associated with decreased insulin secretion and decreased glucose tolerance, which increase the risk of type 2 diabetes.

Key Takeaways

• Eating dinner close to bedtime, when melatonin levels are high, disturbs blood sugar control, especially in individuals with a genetic variant in the melatonin receptor MTNR1B, which has been linked to an elevated risk of type 2 diabetes.
• The high melatonin levels and food intake associated with late eating impairs blood sugar control in carriers of the MTNR1B genetic risk variant through a defect in insulin secretion.

Researchers identified 123 regions in the human genome that are associated with daytime napping and three distinct mechanisms that promote napping. Many napping-related genes also regulate other aspects of sleep.