Saturday, April 16, 2011

How Little Sleep Can You Get Away With?





We all know that we don’t get enough sleep. But how much sleep do we really need? Until about 15 years ago, one common theory was that if you slept at least four or five hours a night, your cognitive performance remained intact; your body simply adapted to less sleep. But that idea was based on studies in which researchers sent sleepy subjects home during the day — where they may have sneaked in naps and downed coffee.

Enter David Dinges, the head of the Sleep and Chronobiology Laboratory at the Hospital at University of Pennsylvania, who has the distinction of depriving more people of sleep than perhaps anyone in the world.

In what was the longest sleep-restriction study of its kind, Dinges and his lead author, Hans Van Dongen, assigned dozens of subjects to three different groups for their 2003 study: some slept four hours, others six hours and others, for the lucky control group, eight hours — for two weeks in the lab.

Every two hours during the day, the researchers tested the subjects’ ability to sustain attention with what’s known as the psychomotor vigilance task, or P.V.T., considered a gold standard of sleepiness measures. During the P.V.T., the men and women sat in front of computer screens for 10-minute periods, pressing the space bar as soon as they saw a flash of numbers at random intervals. Even a half-second response delay suggests a lapse into sleepiness, known as a microsleep.

Read More

No comments:

Post a Comment