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Lack of Sleep Causes Differences In Thinking Patterns
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PITTSBURGH, PA. -- September 15, 1997 -- Burning the midnight oil may do
more harm than good for people who believe they work best at night.

In a study at the University of Pittsburgh Medical Center's UPMC) Western
Psychiatric Institute and Clinic, researchers have found the body's need
for sleep, influenced by its circadian rhythms, may slow down thinking
processes at night.

Also, losing sleep at night can slow down your thinking skills the next day.

>From a practical point of view, results suggest in addition to safety
concerns resulting from night workers' and night drivers' tendency to fall
asleep, it should be recognized that even if they are wide awake, they may
be thinking more slowly.

The UPMC study, published by Timothy H. Monk, Ph.D., professor of
psychiatry, and Julie Carrier, Ph.D., postdoctoral research fellow, in the
current issue of the academic journal Sleep, suggests circadian rhythms,
the body's internal clock, can affect the speed at which the brain
processes information.

According to Dr. Monk, the study's principal investigator, night-time
thinking may slow down because people need to fight their urges to sleep.

Eighteen healthy young adults participated in the 36-hour study that
involved constant wakeful bedrest, or being kept awake while in bed, for
the duration of the study.

Participants also had no knowledge of clock time and meals were replaced by
hourly nutritional supplements. This was done to avoid feelings of
sleepiness that accompany big meals.

A series of performance tests involving figuring out whether sentences were
true or false were given every other hour and the speed and accuracy of the
responses were recorded.

Using questions phrased in both the positive and negative voice, the
researchers found participants took longer to respond to negative-voiced
sentences than positive-voiced ones due to an increase in
information-processing requirements.

By plotting the speed with which this extra processing was done at each
time of day and night, Drs. Monk and Carrier were able to factor out
overall effects of sluggishness and inattention and get directly at the
speed of thought itself.

The study concluded people think more slowly at night, perhaps because they
approach a task differently at night than during the day.

It also showed a slowing in the speed of information processing during the
day after the lost night of sleep.


Copyright 1997 P\S\L Consulting Group Inc.
<http://www.pslgroup.com/dg/38c26.htm>
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