Short sleepers

Tout Va Bien » © JH Engström

 In 2009, a woman came into Ying-Hui Fu’s lab at the University of California, San Francisco, complaining that she always woke up too early. At first, Fu thought the woman was an extreme morning lark – a person who goes to bed early and wakes early. However, the woman explained that she actually went to bed around midnight and woke at 4am feeling completely alert. It was the same for several members of her family, she said. Fu and her colleagues compared the genome of different family members. They discovered a tiny mutation in a gene called DEC2 that was present in those who were short-sleepers, but not in members of the family who had normal length sleep, nor in 250 unrelated volunteers. When the team bred mice to express this same mutation, the rodents also slept less but performed just as well as regular mice when given physical and cognitive tasks.
Getting too little sleep normally has a significant impact on health, quality of life and life expectancy. It can cause depression, weight gain and put you at greater risk of stroke and diabetes.
 “Sleep is so important, if you sleep well you can avoid many diseases, even dementia,” says Fu.
“If you deprive someone of just two hours sleep a day, their cognitive functions become significantly impaired almost immediately.” But why sleep is so important is still a bit of a mystery. continue