Seeing red? Study finds a bad night’s sleep can make you angrier

Sep 28, 2020
A lack of sleep can contribute to a long list of problems, including your emotions. Source: Getty.

We all know a lack of sleep can leave us feeling drained and foggy the next day. However, new research has found that a bad night’s sleep can make you angrier, too.

The study published in the American Academy of Sleep Medicine on Monday analysed daily diary entries from 202 college students, who tracked their sleep, daily stressors and anger over one month. The researchers found participants experienced more anger on days following a bad night’s sleep.

The research team also conducted a lab experiment involving 147 community residents. Participants were randomly asked either to maintain their regular sleep schedule or to restrict their sleep at home by about five hours across two nights. Anger was then assessed during exposure to irritating noise.

The researchers found that well-slept individuals adapted to noise and reported less anger after two days. In contrast, sleep-restricted individuals exhibited higher and increased anger in response to irritating noise, suggesting that a lack of sleep may also undermine emotional adaption to frustrating circumstances.

“The results are important because they provide strong causal evidence that sleep restriction increases anger and increases frustration over time,” Zlatan Krizan from Iowa State University in the US said.

“Moreover, the results from the daily diary study suggest such effects translate to everyday life, as young adults reported more anger in the afternoon on days they slept less.”

A lack of sleep can contribute to a long list of health problems such as heart disease, high blood pressure, diabetes, obesity, early ageing and even Alzheimer’s disease. It comes just a few months after another study found poor sleep may increase your risk of stroke.

In the study published in the open-access journal PLOS Biology in June, the researchers found that people with fragmented sleep tend to have higher numbers of inflammatory white blood cells called neutrophils, which then leads to them having higher coronary artery calcium, a measure of blocked blood vessels. The researchers said this suggests that getting a good night’s sleep may be one way to reduce inflammation and reduce the risk of atherosclerosis (blocked blood vessels), which can cause heart attacks and strokes.

So, how many hours of sleep do we really need? We often hear eight hours as being the magical number to strive for, but in fact, the amount of sleep you need depends on your age. According to a study that ran over two years at the US National Sleep Foundation, the amount of sleep needed can vary from between seven to 17 hours.

Most adults aged 26 to 64 years need about seven to nine hours of sleep per night, while those aged 65 or older need seven to eight hours of sleep per night to feel rested and alert.

IMPORTANT LEGAL INFO This article is of a general nature and FYI only, because it doesn’t take into account your personal health requirements or existing medical conditions. That means it’s not personalised health advice and shouldn’t be relied upon as if it is. Before making a health-related decision, you should work out if the info is appropriate for your situation and get professional medical advice.

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