We all know the feeling: we wake up feeling groggy and exhausted, and no matter how much coffee we drink, we can’t seem to shake the fatigue. We may even start to feel a little bit feverish, and our muscles ache. We may start to crave sleep, even though we’ve been sleeping for hours.
It turns out there’s a reason for that. Scientists have finally uncovered why we crave sleep when we’re sick, and it all has to do with our immune system.
It turns out that when we’re sick, our immune system goes into overdrive. To fight off the infection, our body produces more cytokines, which are proteins that help to regulate the immune system.
However, these cytokines also have a side effect: they make us feel tired. In fact, they actually attach to receptors in the brain that promote sleep.
So next time you’re feeling under the weather, don’t fight the urge to sleep. Your body is just trying to help you heal.