Posted by Brigham and Women's Hospital August 9, 2012
Think that you can get more work done by skimping on shut eye? Not necessarily.
Brigham and Women’s Hospital (BWH) researchers collected and analyzed data on visual search tasks from 12 participants over a one-month study that took place in the BWH Center for Clinical Investigation. In the first week, all participants were scheduled to sleep 10-12 hours per night. For the following three weeks, the participants were scheduled to sleep the equivalent of 5.6 hours per night. They also had their sleep times scheduled on a 28-hour cycle, mirroring chronic jet lag.
Throughout the study, the participants took performance tests several times each day to test how quickly and accurately they could compare two pictures on a computer screen and detect a difference between them. While the accuracy of the participants stayed fairly constant, they were slower to identify the relevant information as the weeks went on.
“We found that the longer the participants were awake, the more slowly they identified the difference between the two pictures in the test,” says Dr. Jeanne Duffy, a researcher in the BWH Division of Sleep Medicine and senior author of this study. “Additionally, during the biological night time (from about 12 a.m. to 6 a.m.), participants, who were unaware of the time throughout the study, performed tasks more slowly than they did during the daytime.”
The self-ratings of sleepiness that the participants gave showed that they felt only slightly sleepier during the second and third weeks on the study schedule, yet the performance test data showed that the participants were performing the visual search tasks much more slowly than the first week.
“This suggests that the perception of tiredness or fatigue does not always match actual performance, and when we cut back on sleep we may not realize how impaired we are by sleepiness,” says Dr. Duffy.
“Our research also provides valuable information for workers, and their employers, who perform visual search tasks during the night shift. They will complete these tasks much more slowly than when they are working during the day, and, because people who work at night are usually awake longer before starting their night shift, they will be doubly impacted.”
How many hours of sleep do you get each night? Tell us how sleep impacts your productivity in our comments section.
– Jessica F