New research has shown why sleep deprivation affects some people more than others. After staying awake all night, those who are genetically vulnerable to sleep loss showed reduced brain activity, while those who are genetically resilient showed expanded brain activity, the study found.

The findings help explain individual differences in the ability to compensate for lack of sleep.

The extent to which individuals are affected by sleep deprivation varies, with some crashing out and others holding up well after a night without sleep, experts on sleep deprivation said.

However, studying how the brain produces these behavioral differences is difficult: researchers usually do not know whether their study participants will be vulnerable to sleep deprivation until after a study is complete.

Previous studies have shown conflicting results, perhaps because the study subjects differed widely in vulnerability to sleep deprivation.

Science Daily