TO CATNAP OR NOT , THAT IS THE QUESTION !

Six-minute nap 'may boost memory'

Even the shortest of catnaps may be enough to improve performance in memory tests, say German scientists.
Just six minutes "shut-eye" for volunteers was followed by significantly better recall of words, New Scientist magazine reported.

"Ultra-short" sleep could launch memory processing in the brain, they suggested.

One UK researcher disagreed, saying that longer sleep was needed to have an impact on memory.

Quote:

This demonstrates for the first time that an ultra-brief sleep episode provides an effective memory enhancement
University of Dusseldorf researchers

Dozens of studies have probed the relationship between sleep and memory, with clear evidence that body's natural sleep-wake cycle plays an important role.

The team from the University of Dusseldorf wanted to see just how short a sleep could have any discernable impact.

They used a group of students who were asked to remember a set of words, then given an hour's break before testing.

During that hour, some of the students were allowed to sleep for approximately six minutes, while the rest were kept asleep.

Remarkably, on waking, the napping students performed better in the memory test.

Some theories suggests that the processing of memories takes place in deep sleep, a phase which does not normally start until at least 20 minutes after falling asleep.

Six minute warning

However, the team, led by Dr Olaf Lahl, said that it was possible that the moment of falling asleep triggered a process in the brain that continued regardless of how long the person actually stayed awake.

"To our knowledge, this demonstrates for the first time that an ultra-brief sleep episode provides an effective memory enhancement," he wrote.

Professor Jim Horne, from the Sleep Research Centre at Loughborough University, said that while the study was "interesting", he was yet to be convinced that the effect was purely one of memory enhancement.

"The idea that memory could be enhanced in just six minutes is a quite unique finding and one has to be rather cautious about it.

"There is quite a bit of evidence that memory processing probably takes place more than six minutes into sleep."


Story from BBC NEWS:
http://news.bbc.co.uk/go/pr/fr/-/2/hi/health/7254555.stm

Published: 2008/02/21 10:30:18 GMT

© BBC MMVIII

Daytime dozing 'stroke warning'
Regular unintentional daytime dozing may be an early warning sign of stroke in elderly people, say US researchers.
For those who had a habit of nodding off, the risk of stroke was two to four times higher than for those who never fell asleep in the day, a study found.

Speaking at the International Stroke Conference, the team advised doctors to check out older people who found they were dropping off in front of the TV.

The study asked 2,000 people how often they dozed off in different situations.

These included while watching TV, sitting and talking to someone, sitting quietly after a lunch without alcohol and stopping briefly in traffic while driving.

Quote:

But the real question is: 'What are we doing to our bodies?'. Sleepiness obviously puts us at risk of stroke
Dr Bernadette Boden-Albala

The risk of stroke over the next two years was 2.6 times greater for people who reported "some dozing" compared to those with no dozing.

Among those who reported "significant dozing" the risk was 4.5 times higher.

The researchers also found the risk of heart attack or death from vascular disease was increased.

Study leader, Dr Bernadette Boden-Albala, assistant professor of neurology at Columbia University, New York, said: "Those are significant numbers. We were surprised that the impact was that high for such a short period of time."

Poor sleep

Previous research has shown that people who suffer from sleep apnoea - short periods when breathing stops during sleep - have an increased stroke risk.

It could be that daytime sleepiness is a sign of sleeping poorly at night because of sleep apnoea.

"Given what's known now, it's worth assessing patients for sleep problems," Dr Boden-Albala said.

"If patients are moderately or significantly dozing, physicians need to think about sending them for further evaluation."

She added other studies had shown people were not getting enough sleep, making them consistently tired.

"But the real question is: 'What are we doing to our bodies?'. Sleepiness obviously puts us at risk of stroke."

Dr Heinrich Audebert, consultant stroke physician at Guy's and St Thomas' Hospital in London said the findings seemed reasonable.

"Sleep apnoea is a risk factor for stroke and in Mediterranean countries the siesta is associated with a little bit of an increased daytime risk of stroke."

He explained that patients with sleep apnoea had increased blood pressure levels during the night.

One other potential cause for the findings could be previous undiagnosed minor strokes causing damage to the brain and leading to more sleepiness during the day, he said.

"What we really encourage is that all patients who have breaks in sleeping in the night should have sleep apnoea screening."

Around 150,000 people in the UK have a stroke every year.

Story from BBC NEWS:
http://news.bbc.co.uk/go/pr/fr/-/2/hi/health/7257270.stm

Published: 2008/02/22 01:05:22 GMT

© BBC MMVIII