It may not be surprising that lack of sleep leaves you less sharp, but researchers have now quantified the effect with a surprisingly large sample: More than 30,000 people who wear Microsoft’s fitness bands and use Microsoft’s Bing search engine.
The results of the study suggest that a couple of short nights can slow you down for days afterward.
“When you don’t sleep well, it affects your cognitive performance, which means your work performance and lots of other things,” lead study author Tim Althoff said in a report on the Microsoft Next blog.
Althoff, who’s working on his Ph.D. in computer science at Stanford University, led the research team last summer during an internship at Microsoft’s research lab in Redmond, Wash. The resulting paper is to be presented in April at this year’s World Wide Web Conference in Perth, Australia.
“This kind of population-scale work has not been done before in sleep research,” said Eric Horvitz, Microsoft technical fellow and director of the Redmond lab.
The study takes advantage of Microsoft Band, a smartwatch that monitors bodily activity (such as sleep patterns). The Band data can be linked to the user’s Microsoft account, including their search activity.
The 30,000 Band users who were involved in the study gave their consent for having their sleep patterns as well as their Bing usage patterns recorded on an anonymous basis. Microsoft’s researchers could tell how quickly those users typed in search queries and clicked on the resulting links.
“Even small differences in the amount of time it would take you to click on the result are indicative of how rapidly you are processing that information,” said another study co-author, Stanford behavioral scientist Jamie Zeitzer. “The idea is people have slower processing speeds as they get more tired.”
The findings, based on an analysis of 75 million keystrokes and clicks, were consistent with smaller-scale studies about the effects of sleep deprivation:
- Users who went just a couple of nights with less than six hours of sleep per night showed signs of a cognitive slowdown for six days afterward.
- Even staying up an extra hour hurt the next day’s typing speed, but going to bed an hour earlier had little effect.
- The average keystroke speeds suggest that the worst time to be tapping away at the computer is around 4 to 7 a.m., and that we’re at our sharpest around 2 p.m.
In the future, researchers might even be able to interpret data about computer interactions such as cursor movements and scrolling behavior to spot the warning signs of neurodegenerative disorders, said co-author Ryen White, chief technology officer for health intelligence at Microsoft Health.
Check out the full report on the Microsoft Next blog.