Researchers say not getting enough rest can make it more difficult to do simple tasks and can lead to frustration.

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A lack of sleep can make you angry more quickly, but there are ways to cope with this sleep-deprived reaction. Getty Images

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.

Relationship between anger, sleep

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.

Dimitriu says sleep has a powerful role to play in our brain health.

When we lose sleep regularly, the brain cannot cope as well.

“Sleep is essential for the body to rest, but even more important for the brain to declutter,” he said. “At night, our brains process the events of the day, put memories into long-term storage, and also make room for new learning to be possible the following day. There is evidence that we also emotionally rehearse scenarios from the past and the future.”

When you cut that rehearsal, storage, and processing time short, your brain isn’t able to do its most important tasks.

How to reverse anger

Being aware that a lack of sleep may make you feel angrier is the first step toward correcting the issue.

When you can recognize the scenarios that frustrate you may lead to anger, you can stop yourself and refocus.

You don’t have to be angry, but you do have to recognize it’s happening before it’s too late.

“If you have been sleep deprived, avoid confrontations with others where your fuse will likely be too short,” Saltz said. “Avoid high-frustration tasks, and save them for another day. If you do pop off, recognize and apologize for a low-sleep day. This is why it’s particularly important to get a good night’s sleep before important events or emotional events.”

If you turn to your trusted cup of coffee for caffeine, it can improve your alertness and your attitude, says Dr. Anne Marie Morse, a neurologist and sleep specialist at Geisinger Medical Center in Pennsylvania.

“Strategic use of caffeine may temporarily fight sleepiness and improve ability to maintain a more calm demeanor,” Morse told Healthline. “Use of caffeine in this manner should be used sparingly, however, and not be used later in the day to avoid interfering with nighttime sleep.”

If you can take a nap, do so, Morse says.

“Taking a nap for 20 minutes may provide the recharge necessary that may contribute to improved self-regulation and a more stable response to difficult situations,” she said.

Of course, you can prevent the anger in the first place by getting more sleep, Dimitrius points out.

“Put the phone away and take it out of the bedroom. Keep regular sleep and wake hours, and avoid alcohol or other drugs, especially before sleep,” he told Healthline.

Saltz says the trope you hear about getting eight hours of sleep each night isn’t an outdated recommendation.

“Try to maintain seven to nine hours of sleep per night,” she told Healthline. “If deprived one night, try to get extra hours of catch-up sleep in the coming week.”

The bottom line

Losing as little as two hours of sleep can make you angrier.

You may be less capable of responding to irritating or frustrating situations because of this factor.

You can prevent these feelings of exasperation by getting more sleep, of course.

But when it’s too late, you can still find relief from the effects.

Recognize the emotional impacts you may experience from the sleep loss and find ways to cope.

You likely can’t blame all of your emotional issues on loss of sleep, but sometimes it helps to know your anger is the result of staying up to finish a Netflix binge and not because you’re an angry person in general.