The prevalence of morningness–eveningness in university-level students of North-East India: Impact on their sleep physiology and metabolic processes

Differences in circadian timing among individuals and the time of day are potential biological sources that might impact student's activities. As previous studies have reported that young adults are more susceptible to sleep deprivation, so the goal of the present study was to investigate the prevalence of chronotype, and its associations between circadian preferences, sleep and its physiological implications, cognitive performances and metabolic profiles among university-level students in the north-eastern parts of the Indian subcontinent. Majority of the students fall in intermediate chronotype in our study with the evening chronotypes having poor sleep quality, leading to low cognitive function that in turn causes periods of anxiety and stress which was reflected in salivary cortisol levels. The evening chronotypes also exhibited lower nocturnal melatonin levels compared to morning types and had difficulty in falling to sleep with elevated oral temperatures. Elevated BMI status and frequencies of fast-food intake were also high in evening chronotypes, which may increase the chances of obesity in them and also prone to hyperglycemia as indicated by higher fasting blood sugar and salivary amylase levels. The metabolic profiles were also altered in late chronotypes as evidenced by low thyroid hormone profiles and higher triglyceride levels. Our study reports intermediate chronotypes along with evening types are at the risk of developing sleep deprived disorders in the future, and it is important that researchers should develop tailored sleep interventions that consider demographic, psychological, and socio-behavioral factors contributing to poor sleep quality, excessive daytime sleepiness, and short sleep duration among students.