Being sick sucks. And while we can't always cure what ails us, researchers at Oregon Health & Science University have figured out where that general feeling of lousiness we get when we're stick actually comes from, and they think they can make it go away.
When you get sick, it usually comes along with one or more acute symptoms: coughing, sneezing, headaches, things like that. But much of the time, you also feel terrible in a more general sense: you're tired and don't have the energy or the desire to do anything, and in some respects, that's the worst part of being sick.
This feeling is caused by your body diverting all of its resources into fighting whatever is making you ill, sapping you of energy and making you not want to do anything besides lie around and sleep. As it turns out, there are a bunch of neurons in your brain that are responsible for producing a neuropeptide hormone called orexin that controls things like wakefulness, appetite, desire for physical activity and overall arousal and interest. When you get sick, the neurons stop making orexin (probably to encourage you to sleep more to let yourself get better), which is where that awful "I'm sick" feeling comes from.
So the question now is, can you just start taking orexin to make yourself feel better? The answer appears to be yes, or at least, so far that's how it works in rats. The good news is that we've known for a while that orexin works as a wakefulness-promoting agent, meaning that drugs that mimic orexin are already well developed. And besides just making you feel less lousy when you have a cold, the hope is that orexin therapy might be able to vastly improve the quality of life for people with chronic illnesses who have to deal with feeling crappy pretty much every single day.