How Not Sleeping Affects Your Mood & Makes You More Aggressive, According To Science

Andrew Zaeh for Bustle

You don’t really need an expert to tell you you’re cranky when you don’t get enough sleep, but just in case someone actually says otherwise, there’s now research to back you up. Iowa State University researchers published a new study in the Journal of Experimental Psychology: General that found lack of sleep makes people angrier, according to a news release. Although the researchers acknowledge the results are pretty much what you’d expect, the study is reportedly one of the first to offer evidence that there’s a clear connection between sleep loss and anger. (The news release doesn’t acknowledge whether any parents of toddlers were consulted prior to commission of this study.)

Previous studies have shown a link between sleep in general and anger, Zlatan Krizan, professor of psychology at Iowa State University, said in a news release, but researchers were unable to determine whether it was sleep loss or sleep disruption that made people angry, or if they were losing sleep due to pre-existing anger. This new study clarifies this distinction, according to the news release, and shows how people adjust to irritating situations when they’re tired.

It’s not every day you get to go to work and try to see if you can annoy other people, but that’s basically what the researchers did. According to the news release, they took a sleep-deprived group and a group that got their regular seven to eight hours of sleep, and they had them rate different products while listening to various noises, like static or spraying water, meant to make them uncomfortable or provoke anger.

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"Despite typical tendencies to get somewhat used to irritating conditions — an uncomfortable shirt or a barking dog — sleep-restricted individuals actually showed a trend toward increased anger and distress, essentially reversing their ability to adapt to frustrating conditions over time. No one has shown this before," Krizan said in the news release.

Despite the researchers assertions, it’s been pretty well-documented that not getting enough sleep can make you a bit hot-tempered, according to Psychology Today. Sleep deprivation increases activity in the amygdala, says Psychology Today, the part of the brain responsible for your emotional reactions. So when you feel overly tired, it can actually make your emotional responses more intense than they normally would be. And it only takes one night of sleep deprivation for you to start feeling a little more irritable or on edge than you typically would, Psychology Today reports.

But lack of sleep can do more damage than just make you cranky. Researchers at the University of California – Los Angeles found that sleep deprivation keeps the brain’s cells from communicating with each other properly. So that foggy feeling you get when you haven’t gotten enough sleep? It’s because your brain cells aren’t quite firing as quickly as they normally do.

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According to the news release, the researchers involved in this new study acknowledge that the association between sleep loss and negative emotions, such as anxiety and depression, has been well-documented in the scientific community, but their interest was specifically in sleep’s association with anger. In the future, says the news release, they hope to study how sleep might be linked to aggression.

Well, there you have it. Science has now backed up the crankiness every single person on the planet has experienced after a bad night’s sleep. Does this mean companies will now sanction workplace naps? Hey, a girl can dream, right?