Sleep deprivation linked to more negative effects for cognitive function than earlier theories suggest
Sleep deprivation makes people more prone to errors than scientists previously thought, according to a recent study by researchers at the Michigan State University’s Sleep and Learning Lab.
Published in the Journal of Experimental Psychology: General, it showed that people were thrice more likely to have lapses in concentration and twice more likely to make placekeeping errors after one sleepless night.
This is the first study to assess the effects of sleep deprivation on placekeeping, a high-level cognitive function that refers to a person’s ability to complete a series of steps without missing or repeating one despite interruptions.
Lead author Michelle Stepan and her team are hopeful their study will convince people to acknowledge how their abilities are hindered by lack of sleep. They also said that their findings debunk the idea that sleep deprivation only affects attention.
Sleep deprivation leads to errors, lapses in concentration
Previous studies have shown that sleep deprivation negatively affects people’s ability to pay attention, leads to poor decision-making and slows reaction time.
For their study, the researchers sought to analyze how sleep deprivation also affects placekeeping. They recruited 138 participants aged 18 to 25 years for an overnight sleep assessment. None of them had any memory or sleep problems, or a strong time-of-day preference.
The researchers asked the participants to sleep for at least six hours the night before the assessment. They also asked the participants to refrain from napping or drinking anything with caffeine or alcohol.
As part of the assessment, the participants performed two cognitive tasks. One task measured their reaction time to a stimulus, while the other task measured their placekeeping ability. After completing the tests, 77 participants remained at the laboratory and stayed awake all night, while the remaining 61 were sent home to sleep as usual.
Both tasks were repeated for all the participants the following morning. The researchers then compared the two sets of results to see how sleep deprivation affected placekeeping.
The results showed that for the first set of tasks designed to assess placekeeping ability, there was a 15 percent error rate among the participants following interruptions. That error rate doubled to 30 percent the next morning for the participants who stayed awake all night. In contrast, the rate remained the same for those who slept.
Sleep deprivation also tripled the odds of experiencing lapses in attention, said co-author Kimberly Fenn. These results suggest that completing activities that require following several steps, like completing a medical procedure, is much riskier under conditions of sleep deprivation.
Studies show that people can still do routine tasks even when sleep-deprived. But what the present study suggests is that sleep deprivation can cause widespread deficits across all facets of life.
Sleep deprivation reduces neural activity
Sleep is an important time for the brain. During sleep, the brain eliminates waste accumulated during the day. Sleep also “resets” the buildup of connectivity in the brain. This reset allows synapses to relax and prepare for the next day’s new input.
Forgoing sleep or sleeping for only a few hours hinders those important processes from taking place, resulting in sluggishness, tiredness and brain fog.
A 2017 study found that depriving the body of sleep also robs brain cells of the ability to function properly. In the study, participants were asked to stay up for an entire night. During that time, they were asked to categorize images of faces, places and animals as fast as possible.
When the researchers looked at the participants’ brain activities, they found that the more the participants got tired, the more challenging the task of properly categorizing images became for them. The activity of their brain cells also started to slow down considerably.
The researchers also found that those regions of the brain that became sluggish were the same regions that would normally become active during sleep. Moreover, they found that sleep deprivation exerts a similar influence on the brain as drinking too much alcohol. These findings clearly emphasize the importance of sleep on ensuring that the brain functions optimally.