If you’ve ever had a bad night of sleep, you probably also know that you don’t feel so great the next day. Aside from being horribly sleepy, you may have also noticed that you just don’t feel right. You’re cranky and the day can feel like an emotional roller coaster. New research published recently has figured out why keeping an even keel is so hard when you’re sleep deprived. Their research reveals that your brain responds differently to information in a way that makes it hard for you to react normally to things that shouldn’t bother you.
How did the researchers study emotion and sleep?
The team recruited 18 healthy men and women between 23 and 32 with no previous sleep problems. The researchers randomly assigned half to be sleep deprived for the night before having to come into the lab and the other half got a normal night of sleep. To make sure the participants were well rested before starting the whole experiment, the team told them to stay away from alcohol and caffeine for two days before testing and monitored them three nights before to make sure they got normal amounts of sleep. When the participants came into the lab, they did tests while being monitored with two different machines. The first, called an EEG, measures the electrical patterns your brain makes when it’s active. The other, called a functional MRI or fMRI for short, can take pictures of your brain working in real time and can measure which parts are working the hardest.
The participants were given a series of difficult tasks to do and were interrupted every now and then with pictures that were emotionally charged or neutral. For example, a participant might be trying to remember a list of numbers and suddenly see a sad face or an angry face. Some of the pictures were neutral, like a picture of a spoon. During this whole process, the activity of their brains was recorded. The participants regularly recorded how sleepy they felt and what their mood was. This was a crossover study, which meant that the participants who were sleep deprived repeated the experiment with sleep two weeks later and those who got sleep repeated it sleep deprived two weeks later.
What did the team find out about sleep deprivation and emotion?
As expected, the participants’ mood shifted with sleep deprivation, and they felt fewer positive emotions over the course of the testing. The participants were also worse at completing the complex task they were asked to do and had more trouble concentrating when distracting images showed up. A key finding was that the brains of those who were sleep-deprived spent much more time stuck on neutral images than those who were not sleep deprived. Rather than passing over these images as nothing to worry about, the emotional parts of their brain reacted to them. It was as if the brain couldn’t tell what was supposed to cause an emotional response and what wasn’t.
When the team looked at the EEG and fMRI results, they saw that the parts of the brain that normally responsible for an eye on the emotional parts of the brain weren’t working the way they were supposed to. This was particularly the case when the task at hand was challenging or stressful, but also happened with easy or repetitive tasks. The results went beyond past studies in showing that the brain responded more emotionally than normal to neutral things. The brain was suddenly responding with emotion to things that weren’t supposed to be emotional because sleep deprivation had lessened the ability of other parts of the brain to control that response.
What does this mean for me?
This study reminds us just how damaging losing sleep can be to our overall mental well-being. When you start crying for no reason or yell at someone for a small thing after a sleepless night, it’s because your brain isn’t able to control your emotions the way it should. But even beyond that, you’ll start to get emotional over things that really shouldn’t be. This study shows us that when you’re sleep deprived, your brain starts to have an emotional response to situations and objects that shouldn’t make you feel happy, sad or angry. If you feel like you’ve been on an emotional roller coaster lately, it might be helpful to try and get a good night’s sleep.