A study from the National University of Singapore shows that split and continuous sleep schedules both result in similar neurocognitive performance of adolescents – as long as they receive the recommended number of hours of sleep per day.
It may come as a surprise to some to learn that the amount of sleep that adolescents should get per day remains a contentious issue. The effects of sleep deprivation on adolescents’ cognition and mood are often studied and used to evaluate if students’ performance are suffering as a result of insufficient sleep.
The question of whether adolescents today are getting enough sleep is especially relevant given the tendency for students to receive much fewer hours of sleep than is recommended. This is true particularly for adolescents in academically competitive societies, who often do not get enough hours of sleep at night. In Singapore, for instance, it is estimated that 85 percent of secondary students (aged between 12 and 16) regularly obtain less than the recommended eight to ten hours of sleep per night.
To compensate for insufficient sleeping hours, students who sleep less at night on weekdays have a greater tendency to take naps on weekdays and to sleep for longer durations on weekends.
Researchers from the National University of Singapore (NUS) published a study recently in the journal Sleep, in which they observed the neurocognitive effects of split sleep schedules vs continuous sleep schedules. The study included 53 adolescents aged between 15 to 19, over 15 days in order to mimic 1.5 school-term weeks.
To compare the effects both types of sleep schedules, participants in the study were categorised into two groups. On “school nights”, both groups received a total of eight hours of sleep per 24-hour day; however, participants on split sleep schedules had a 1.5 hour mid-afternoon nap and 6.5 hours of nocturnal sleep, as opposed to participants with continuous sleep schedules who received an uninterrupted eight hours of sleep every night.
The cognitive performance of each participant was assessed three times a day, and the data obtained was similar between participants on the split-sleep schedule and continuous sleep schedule, without significant differences in cognitive function, alertness, and mood.
In other words, the findings of this study suggest that such split sleep schedules that include structured naps in the afternoon may be practical solutions for students who are unable to get the full eight hours of sleep per night.
This study, among four other previous ones, is part of a series of “Need for Sleep” studies. Previous investigations by the team of researchers examined the neurocognitive and neurobehavioral effects of different sleep schedules in adolescents. The team’s past findings also revealed valuable information about sleep requirements in adolescents and the effect of sleep patterns on cognitive performance.
Specifically, this series of studies demonstrated that when the total number of hours of sleep per day is decreased, naps can help to alleviate the negative effects suffered, but cannot fully restore the effects of insufficient sleep, even in high performing students. Interestingly, cognitive performance could be preserved, but with consequences to glucose metabolism and possibly other metabolic processes. Therefore, these studies suggest that the best way to preserve cognitive function is to ensure that one gets sufficient sleep over the day.
All of this seems to indicate that structured afternoon naps may be beneficial in the restoration of cognitive function, alertness, and mood in individuals who do not get enough sleep at night, as long as one gets the recommended number of hours of sleep over the entire day.
Professor Michael Chee, Director of the Centre for Sleep and Cognition at the Yong Loo Lin School of Medicine in NUS, remarks that “prior to modern ‘advancements’, taking a mid-afternoon nap was common in East Asia. Ironically, it may take 21st Century ‘rediscovery’ to restore a practice that might well have been discovered through empirical means centuries ago.”
Perhaps the key to greater productivity could be taking time off in the middle of the day to get some shut-eye.