Decision making after awakening from sleep

From the Financial Express:

Professionals like doctors and pilots, who are suddenly woken up from deep sleep, need to take some time before taking major decisions, a new study has concluded.

Researchers have found that people are as woozy when they wake up as they are after drinking several beers, 'nature' magazine said. Sleep researchers have long been interested in the symptoms of sluggishness and disorientation that people experience after awakening, which they call sleep inertia.

Now they have measured exactly how hopeless early-morning brains are at carrying out everyday tasks.

Kenneth Wright at the University of Colorado, and his co-workers looked at the mental handicap caused by sleep inertia, and compared it with the detriment of having stayed up all night.

They allowed nine volunteers to enjoy roughly eight hours' nightly slumber for four weeks, the final week taking place in the lab.

After a final pleasant night's sleep, they woke each person and immediately, without even a cup of coffee, asked them to calculate a string of sums. Then they scored how many problems each one totted up correctly over two minutes.

The test was then repeated after 20 minutes and again at regular intervals until the subjects had gone a full 26 hours without sleep.

Brain power was worse in the first few minutes after awakening than it was after a whole night's sleep deprivation, the report in the 'journal of the American Medical Association' said.