[fuyumi]

NEW YORK - TEENAGERS should be encouraged to get up on weekends at roughly the same time they get up for school during the week, experts said based on new research that suggests that sleeping late on weekends may lead to poor academic performance.

The research was discussed today at SLEEP 2007 - the 21st annual meeting of the Associated Professional Sleep Societies.

Lead researcher Stephanie J. Crowley noted that teenagers' sleep is typically restricted during the school week; they often stay up late due to homework and have to rise early to get to class.

As a result, they often try to 'catch up' on weekends by sleeping later and longer.

In an ongoing study, Ms Crowley of Brown University in East Providence, is examining the impact of this typical teenage sleep pattern on a group of high school students.

Preliminary results, based on six 15- to 16-year-olds, show that staying up late and sleeping in over the weekend resets the body's internal clock to a later time, Ms Crowley said, making them foggy on Monday morning.

'This resetting pushes back the brain's cue to be awake on Monday morning for school,' she said.

'Essentially, teenagers may be giving themselves jetlag over the weekend even without getting on a plane,' she added.

Ms Crowley is also finding that weekend 'catch up' sleep makes teens less attentive on Monday morning.

'So far, what we are finding is that with this large mismatch between the internal clock and sleep behaviour that sustained attention in the morning, especially on Monday morning, shows decrements,' she said.

Experts recommend that teenagers get about nine or more hours of shut eye each night, but studies show that most, in reality, may only get a little over 7 hours of sleep each night.

Based on the current study, teenagers should be encouraged to get a full night's sleep on a nightly basis and to get up at the roughly the same time every morning, even if they stay up late on Friday and Saturday night - although this may be easier said than done.