By Anuj Chandra, M.D., D.ABSM
When you work late at night, you probably know you're
feeling more and more tired. But researchers have found that your actions may
get slower and slower, even if you don't realize what's happening.
Researchers in Brigham and Women's Hospital in Boston have found that lack of sleep can affect
how you perform certain tasks, regardless of how tired you think you are. The
findings were published last week in the online Journal of Vision.
After a preliminary week in which participants slept 10-12
hours a night to be sure they were well rested, the next three weeks had
participants sleeping about 5.6 hours per night, following a 28-hour cycle to
duplicate the effect of chronic jet lag. Researchers asked participants to
perform visual search tasks and recorded how quickly and accurately they were
able to find and identify visual information.
As study participants stayed awake longer, they identified
information more and more slowly. If they were working from midnight to 6 a.m.,
participants were slower than they were during the day. As the weeks went on, participants'
accuracy continued to be fairly consistent, but they slowed down further. Their
self-ratings of sleepiness declined only slightly, but the data showed that
they were significantly slower.
While it may seem obvious that being sleepy slows you down, this
research has significant implications for employers and workers. The lessons
are that people who do this type of work during the night shift will be
significantly slower. The later they work the slower they will be, and they may
not realize they are impaired.
