A new study adds to the evidence that sleep deprivation has a significant effect on our day-to-day functioning. The authors warn that if we have slept poorly overnight, we are twice as likely to commit errors, some of which may well be very costly.

Having a good night's sleep is key to maintaining both physical and cognitive health. Our bodies know this instinctively, and researchers have proved many a time that this is true.

For example, at Medical News Today, we have covered studies showing that sleep protects vascular health, helps maintain brain health, and may even give the immune response a boost.

Conversely, poor sleep may lead to cardiovascular disease, contribute to depression, and increase a person's risk of diabetes.

Some researchers have also warned that sleep loss can affect aspects of our memory and visual perception so severely that driving after a sleepless night can be as dangerous as drunk driving.

Following on from such evidence, researchers from Michigan State University's Sleep and Learning Lab in East Lansing have conducted further research on sleep, attention, and higher order cognitive functioning.

Their findings, which feature in the Journal of Experimental Psychology: General, show that sleep loss has an important effect not just on how well we can maintain our focus, but also on how well we can follow complex procedures — an aspect that they refer to as "placekeeping."

Sleep deprivation can be 'risky'

For their study, the investigators recruited 138 participants, whom they split into two groups: 77 people stayed in the laboratory overnight and had no sleep, while the remaining 61 participants slept at home.

The evening before, all of the volunteers took part in two tasks. The first one measured their reaction time to a particular stimulus, and the second one assessed their placekeeping abilities — that is, how well they were able to follow the particular steps of a complex process even with repeated interruptions.

On the morning after, each participant had to repeat these tasks to see how their performance compared with that of the previous evening. The researchers found that the participants who had experienced sleep deprivation struggled significantly.

"Our research showed that sleep deprivation doubles the odds of making placekeeping errors and triples the number of lapses in attention, which is startling," says study co-author Kimberly Fenn.

"Sleep deprived individuals need to exercise caution in absolutely everything that they do and simply can't trust that they won't make costly errors. Oftentimes — like when behind the wheel of a car — these errors can have tragic consequences," she warns.

Although it may not come as a surprise that lack of sleep reduces a person's ability to focus, the researchers note that their recent study shows that sleep deprivation actually affects higher cognitive functioning, interfering with memory recall to a large extent.

"Our findings debunk a common theory that suggests that attention is the only cognitive function affected by sleep deprivation," says first author Michelle Stepan.

"Some sleep deprived people might be able to hold it together under routine tasks, like a doctor taking a patient's vitals. But our results suggest that completing an activity that requires following multiple steps, such as a doctor completing a medical procedure, is much riskier under conditions of sleep deprivation." Michelle Stepan

"After being interrupted [as they were performing complex tasks], there was a 15% error rate in the evening, and we saw that the error rate spiked to about 30% for the sleep deprived group the following morning," notes the first author.

"The rested participants' morning scores were similar to the night before," she adds. This finding, the investigators argue, should serve as a warning to people who experience sleep loss not to underestimate the effect that it can have on their daily lives.

"There are some tasks people can do on autopilot that may not be affected by a lack of sleep. However, sleep deprivation causes widespread deficits across all facets of life," Fenn emphasizes.