Endocrine Abstracts

Background: The median sleep time per night has been declining in the world consistently over last 5 decades. The timing of sleep is distinct characteristic of sleep patterns that may impact metabolic disease risk independent of sleep duration, possibly through the effects of circadian rhythms on metabolism. The sleep and wake up timings are driven by both endogenous circadian rhythms that regulate sleep propensity, energy homeostasis and metabolism as well as by sociocultural factors that influence behaviour. As diabetes mellitus carries a high risk of cardiovascular-related mortality, the impact of sleep deprivation on glucose regulation suggests a mechanism whereby short sleep time might increase mortality.

Aim: Aim of our study was to determine the association of wake-up timings with fasting plasma glucose levels in rural Indians.

Materials and Methods: 512 diabetic patients between age group 25 years to 75 years who visited our hospital in rural India from September 11, 2020 to June 15, 2021 were studied. Sleep timings and wake up timings were noted. Fasting plasma glucose levels were obtained by venepuncture after an overnight fast of at least 8 hours and blood glucose estimation done by the hexokinase method. One way ANOVA and post hoc Tuckey test were used for analysis.

Results: We found that fasting plasma glucose was significantly higher in patients who wake up after 0700 hours compared with patients who wake up early before 0600 hours. This difference was statistically significant with P value of less than 0.001. Furthermore, fasting plasma glucose values were significantly less (better) in the patients who wake up before 0500 hours. Conclusions Our study supports that waking up early (before 0600 hours) in the morning can lead to better fasting glucose levels compared to those who wake up after 0700 hours. One possible explanation for these associations is circadian disruption, which occurs when different endogenous circadian rhythms are not synchronized with one another and/or with the external world. Circadian disruption could occur when the timing of volitional behaviours, including sleeping and eating, are not aligned with the endogenous circadian rhythms of associated physiological processes, such as sleep propensity, insulin sensitivity, or glucose metabolism. Waking up early provides more time to do physical activity and also for recreational purpose which leads to better fasting blood glucose levels. Further research is necessary to determine whether sleep and wake up timings do in fact lead to alterations in glucose metabolism.