Why Sleep Deprivation Causes Bad Moods – and What You Can Do About It

By Deluxe Sleep · Published on 28 July 2026

Why Sleep Deprivation Causes Bad Moods – and What You Can Do About It

Sleep is not just pleasant and restorative – it is essential to our health. When we lack sleep, we often wake up tired and worn out, and our emotional balance is also thrown off during the day. This increases our irritability and reduces our even-temperedness. The result: we're in a bad mood. So that we can start the day with enough energy and enjoyment, regular sleep is a must. Read on to find out why sleep deprivation causes bad moods, what you can do about it, and why our brain plays an important role in this.

This is why sleep deprivation causes bad moods

If we don't get enough sleep, our well-being suffers. We feel exhausted and have trouble concentrating during the day. Beyond that, scientific studies show that too little sleep also takes a toll on our mood. Poor sleepers are three times more likely to be irritable than well-rested people and react in ways that don't match their personality. Sleep deprivation can even encourage feelings such as anger, anxiety and depression.

If the connection to our emotional center, the amygdala, is disrupted, the brain can no longer properly regulate our emotions.

How does sleep deprivation affect our brain?

While we sleep, our brain processes thousands of impressions and experiences from the day that has passed. If this rest phase is interrupted or shortened by sleep problems, the connection to our brain's emotion and fear center is disrupted. The so-called amygdala can then no longer properly regulate our emotions, since it can no longer distinguish between emotional and neutral information. The cause of this is the weakened connection, due to the lack of sleep, to the prefrontal cortex, which normally controls our amygdala and tempers its reactions. Not only do we feel drained and tired after sleepless nights, but because of our amygdala we also react to neutral stimuli more emotionally and more irritably than usual. Where we can otherwise tell the important from the unimportant well, this is no longer possible. So if you haven't had enough sleep, it's best to steer clear of provocations or bigger problems that day – or take them with a sense of humor.

Meditation and breathing exercises in the morning

If you found the night not very restful, it's now important to start the day well. One option is to meditate in the morning after getting up. Combined with breathing exercises, this helps restore your inner calm. You should take enough time for this, because the wait pays off. Not only does it give you a clear head, it also helps you become more alert. That way you can still start the day feeling balanced after all. These exercises are also very useful if, in the evening before going to sleep, you already dread the night ahead. The meditation exercises help you settle down and switch off, so that you can fall asleep more easily afterward. If you suffer from frequent sleep deprivation, you should practice them regularly, since they reduce the reactivity of the brain's emotion and fear center.

Fresh air does you good

Especially during the long winter months – when we tend to spend more time indoors anyway – fresh air is a real treat. If your sleep has suffered during this time, try a ten- to thirty-minute walk in the morning. This eases the tension and fatigue that built up during the sleepless night, and the day can start off gently. Out in nature, our mind can wake up calmly, without the overstimulated amygdala being overwhelmed by additional, constantly incoming impressions from smartphones and the like. In addition, sunlight floods our body with endorphins, the happiness hormones. Our vitamin D stores are also replenished, and the body gets going. Did you know that a quiet evening walk can also help you fall asleep, if you use it to switch off?

Start the day with energy

It's not for nothing that people say breakfast is the most important meal of the day. That's because a hearty meal can provide a lot of energy. This matters all the more because hunger, too, can make us irritable and aggressive. After a night of poor sleep, bananas are especially good, since they contain a high proportion of vitamin B6, which can counteract exhaustion. The potassium and tryptophan they contain can also improve your mood and lower your irritability threshold. Whole-grain products are also a good source of energy. They contain the important nerve vitamins B1 and B2, which support normal energy metabolism and reduce fatigue. As a drink, a cup of cocoa is a good choice, since it activates our happiness hormone serotonin. And if you have no time in the morning, you can prepare something small the evening before. Overnight oats work best for this. That helps save time in the morning and lets you go to bed with a satisfied feeling in the evening.

Conclusion

If we don't get enough sleep, our well-being suffers, since the amygdala, our emotional center, is disturbed in its rest phase. So that we don't go through the day in a bad mood and overstimulated, it's therefore important to sleep well. If that wasn't the case, you can try meditation, a soothing walk, or a balanced breakfast to counteract the existing sleep deficit and recharge with new energy. But in the evening too, meditation and a quiet walk in nature can help you switch off better from everyday stress and then fall asleep more easily. That way, you can still look forward to deep, healthy sleep after all.

Source: This article is based on an article from the BICO sleep blog (bico.ch). The scientific study results mentioned in it come from the respective underlying research, not from us.