New York, Jan 16 (IANS): Is your school-going kid sleep-deprived or throws tantrums? Blame it on early school timings, says a study.

If school schedules are aligned with adolescents' circadian rhythms - physical, mental and behavioural changes that follow a roughly 24-hour cycle - and sleep needs, the students would be more alert, happier and better prepared to learn.

“We would then have kids not dependent on caffeine and energy drinks just to stay awake in class,” said Julie Boergers, co-director of the Pediatric Sleep Disorders Clinic at Hasbro Children's Hospital in Rhode Island, US.

The problem is particularly acute among teenagers as most of them undergo a biological shift to a later sleep-wake cycle, said the study published in the Journal of Developmental and Behavioural Paediatrics.

Sleep deprivation is epidemic among adolescents, with potentially serious impacts on mental and physical health, safety and learning.

“Early high school start times contribute to this problem,” stressed Boergers.

Boergers' team monitored students attending an independent high school after their school start time was experimentally delayed from 8 to 8.25 a.m. during the winter term.

The experiment showed that daytime sleepiness, depressed mood and caffeine use were all significantly reduced after the delay in school start time.

More interestingly, the later school start time had no effect on the number of hours students spent doing homework, playing sports or engaging in extracurricular activities, the study said.

"The results of this study add to a growing body of research demonstrating important health benefits of later school start times for adolescents," Boergers added.