Why a Lack of Sleep Can Make You Angry

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When you slack on shut-eye, you won’t just develop bags under your eyes.
You may also develop anger issues.
New research from Iowa State University reveals that people who lose just a few hours of sleep at night are angrier and less capable of adapting to frustrating situations than people who get adequate rest.
The results, which were published in Journal of Experimental Psychology: General, are among the first to link sleep loss to an increase in anger.
Previous studies have suggested a possible link between the two factors, but it was unclear if sleep loss increased anger or if anger led to the sleep loss.
“Sleep-restricted individuals actually showed a trend toward increased anger and distress, essentially reversing their ability to adapt to frustrating conditions over time,” Zlatan Krizan, PhD, study author and professor of psychology at Iowa State University, said in a statement. “No one has shown this before.”
What the study showed
The researchers divided 142 participants into two groups.
The first group maintained their normal sleep routine.
The second cut their sleep short by two to four hours each night over two nights.
The group that maintained their normal sleep averaged about seven hours of sleep.
The second group had just four and a half hours of sleep a night.
This may seem like a steep difference, but Krizan says it was designed to replicate the sleep loss many Americans experience daily.
After the two nights of the sleep study, participants were asked to come to a lab where Garrett Hisler, an Iowa State doctoral student and study co-author, had them perform product reviews while listening to one of two types of noise.
The first, brown noise, is akin to the sound of spraying or showering water. While not relaxing, it’s less abrasive than the other noise option.
The second, white noise, was more grating. Its sound resembled static.The noises were intended to make the participants uncomfortable and to see if they would produce an anger response during their time in the lab.
As the researchers expected, people who had been sleep restricted reported more anger, regardless of the type of noise.
“In general, anger was substantially higher for those who were sleep restricted,” Krizan said.
During the review, the researchers manipulated the noise sounds to make them more annoying.
When the noise was at its most unpleasant, feelings of anger were at their highest.
Sleep loss and lack of quality sleep have long been connected with a variety of physical, mental, and emotional impairments.
In the short term, sleep loss can increase negative emotions, such as anxiety, restlessness, and sadness.
It can also decrease positive emotions, dampening feelings of happiness, enthusiasm, or joy.
Studies show that sleep loss makes you less capable of turning down junk food.
Poor sleep quality may also impair how well your body responds to insulin, which can lead to increased appetite and obesity.
“Over time, high stress caused by less sleep affects mood further,” said Dr. Gail Saltz, an associate professor of psychiatry at the New York-Presbyterian Hospital, Weill-Cornell School of Medicine. “So long-term depression can be an issue. High stress causes release of cortisol, and this in turn takes a toll on the body via high blood pressure and cognitive decline.”
These latest findings add to the growing evidence that suggests lack of sleep and poor quality sleep is a major health concern for Americans.
“Lack of sleep can result in a wide variety of symptoms, which are fortunately reversible once sleep is restored,” said Dr. Alex Dimitriu, who is double-board-certified in psychiatry and sleep medicine and founder of Menlo Park Psychiatry & Sleep Medicine.