People who go to bed at the same time every night are far more healthy and successful than their more spontaneous peers, new research reveals.
While the growing swell of sleep research tends to focus on the amount of time we sleep, scientists have found routine is just as key.
A team measured sleep and circadian rhythms in 61 undergraduates for 30 days using sleep diaries, then compared that data to their academic performance, According to the Daily Mail.
Overwhelmingly, students with irregular patterns of sleep and wakefulness had a lower grade point average than the rest.
They also tended to hit snooze more often, rather than bounding out of bed, and struggled to get sleepy, due to irregular releases of melatonin – the hormone that makes us want to sleep.
The research is one of the first studies to have considered or accurately quantified the effects of regular sleep patterns.
It suggests a more inconsistent routine prevents your body from releasing hormones at the right time to make you feel sleepy and awake, thereby throwing off your circadian rhythm (body clock).
In the study, the researchers quantified sleep regularity using the sleep regularity index (SRI), a newly devised metric.
They examined the relationship between the SRI, sleep duration, distribution of sleep across the day, and academic performance during one semester.
‘Our results indicate that going to sleep and waking up at approximately the same time is as important as the number of hours one sleeps,’ said Dr Andrew J. K. Phillips, a biophysicist, and lead author on the paper.
‘Sleep regularity is a potentially important and modifiable factor independent from sleep duration,’ Dr Phillips said.
Students with more regular sleep patterns had better school grades on average.
Researchers found no significant difference in average sleep duration between most students with irregular sleep patterns and most regular sleepers.
‘We found that the body clock was shifted nearly three hours later in students with irregular schedules as compared to those who slept at more consistent times each night,’ said Dr Charles A. Czeisler, senior author on the paper.
‘For the students whose sleep and wake times were inconsistent, classes and exams that were scheduled for 9am were therefore occurring at 6am according to their body clock, at a time when performance is impaired.
‘Ironically, they didn’t save any time because in the end they slept just as much as those on a more regular schedule.’
The team could identify each students circadian rhythm by measuring when their body released melatonin.
They saw that students who went to bed at different times every night tended to release melatonin 2.6 hours later than their peers.
‘Using a mathematical model of the circadian clock, we were able to demonstrate that the difference in circadian timing between students with the most irregular sleep patterns and students with regular sleep patterns was consistent with their different patterns of daily light exposure,’ Dr Phillips said.
‘In particular, regular sleepers got significantly higher light levels during the daytime, and significantly lower light levels at night than irregular sleepers who slept more during daytime hours and less during nighttime hours.’
The researchers concluded that light-based interventions – such as spending more time outdoors in the sunshine and spending less time on computers screens at night – may be effective in improving sleep regularity.
N.H.Kh