A sleepless night may impair your reflexes the next day as much as knocking back a few drinks would. That’s because your brain cells are trying to grab the shut-eye they missed out on, a new study suggests.
Researchers found sleep deprivation can make brain cells sluggish and communication slow, according to the study published in Nature Medicine. The implications are huge: If you’re driving on the highway and a car stalls out in front of you, for example, you might not notice fast enough to stop or swerve to avoid it.
The effect is similar to what you see when someone has been drinking, said Dr. Itzhak Fried, a professor of neurosurgery at the University of California, Los Angeles. Making matters worse, while “we have ways to measure drunk driving, we don’t have fatigue measures,” Fried said.
Although previous studies have shown sleep deprivation can be as impairing to a driver as alcohol, no one knew why. The new research shows lack of sleep slows down a region of the brain involved in visual perception and memory.
Fried and his colleagues were able to examine the behavior of individual brain cells with the help of patients who had epilepsy that couldn’t be helped by medications. The only option for these patients is surgery to remove the brain cells that spark a seizure. To find the culprit brain cells, doctors implanted electrodes in the patients’ brains and then watched to see where the seizures started. The patients were asked to stay up through the night on occasion because lack of sleep can trigger a seizure.
Realizing that the conditions were perfect for observing the impact of sleep deprivation on the performance of individual brain cells, the researchers asked for volunteers to participate in an experiment. The 12 who signed on were asked to watch a series of photos that flashed quickly on a screen and to immediately identify whether the image was of a face or something else.
The researchers saw a big difference in how volunteers’ brains performed during the experiment. The sleep-deprived ones were slower at performing the task and the brain cells in their temporal lobes fired more weakly and sluggishly.
There was another phenomenon linked to the lack of sleep: The kinds of waves that wash across people’s brains during sleep were observed in certain areas even when volunteers were awake. Those “slow waves” suggest parts of the volunteers' brains were “dozing, causing mental lapses, while the rest of the brain was awake and running as usual.”
Fried suggests the best way to avoid the phenomenon is to get a good night’s sleep. If that’s not possible, "cat naps,” during the day might help, he said. “There are studies that show that even short naps can help quite a bit,” he added.