• Partial sleep deprivation – five hours of sleep for seven nights – in teenagers resulted in a significant decline in several cognitive functions.
• Even after two nights of recovery sleep, cognitive shortcomings could still be observed.
• Even students from top high schools are susceptible to the adverse effects of partial sleep deprivation.
 
Researchers at Duke-NUS Medical School (Duke-NUS) found that teenagers who sleep only five hours a night for a week experience significant decline in cognitive functions. These findings caution against insufficient sleep by many students in their pursuit of higher grades.
 
In their ‘Need for Sleep’ study, Duke-NUS researchers evaluated 56 teenagers, aged 15 to 19 years, as they lived in a boarding school for 14 days during their school holidays. For seven nights, half of the participants had five-hours of sleep each night, while the other half had nine hours– the recommended sleep duration for this age group by the National Sleep Foundation in the United States.

 

The researchers found that those in the nine-hour sleep group either maintained cognitive performances or showed improvements in tasks requiring calculation and investigation.

 

In contrast, those in the five-hour sleep group showed significant decreases in attention spans, remembering details, managing time, alertness, and positive mood. They also showed reduced levels of performances in tasks requiring calculation and investigation.

 

A sobering discovery was that two nights of nine-hour recovery sleep could not fully reverse some of these cognitive shortcomings brought about by the lack of sleep.

 

 

“Despite the fact that most of our participants were from elite schools they were not spared the adverse effects of sleep curtailment on their cognitive functions,” said Dr June Lo, the lead author and a Duke-NUS Senior Research Fellow.
 
Contextualising the findings to an Asian setting befitting Singapore, Professor Michael Chee, senior author and Director of the Centre for Cognitive Neuroscience at Duke-NUS, said, “East Asian societies highly value academic achievement as a yardstick of success and the need to push harder and for longer is deeply ingrained. The present findings should cause students, parents and educators to reflect on how they use time more efficiently to allow for sufficient nocturnal sleep.”
 
This research was published on 1 March 2016 in the journal SLEEP, and is supported by the National Research Foundation Singapore under its Singapore Translational Research Investigator Award (NMRC/STaR/0004/2008), the Singapore Ministry of Health (MOH)’s National Medical Research Council (NMRC) under its Singapore Translational Research Investigator Award (NMRC/STaR/0015/2013) and the Far East Organization.