Sleeping Infections away


Maybe you should just turn off the computer and get some Zzz's. You'd feel better - and maybe you won't catch a cold.

It seems intuitive

You know how it is when you just can't catch a break. You have a lot to do. You're working around the clock. Maybe you're pulling all nighters studying. You need more time. Then, you get a whopping cold and you can't get anything done.

Sleeping more might really be good for you.

Those who sleep less may be more likely to catch a cold. In some way, their immune system may be weaker.

Those who sleep 6 hours or less a night may be 4x more likely to catch a cold (if exposed) than those who slept over 7 hours. Researchers had a group of people (164 men and women) record the amount of sleep they had each night at home over 1 week. They then had them to a hotel, be quarantined, have a virus (rhinovirus) sprayed up their noses. Most did not become sick. Those who did were more likely to have had less sleep. Those who had 6 hours were more likely to get sick than those who had 7 hours; those who had 5 hours were even worse off.

This is bad news for many Americans. About 1 in 5 Americans sleep less than 6 hours of sleep a night.

All those smartphones may affect not just our sleep, but also our health. Taking work home may not be a good idea. What also might not be a good idea are all those beeps and all that racket inemergency department or in the Intensive Care Unit, as patients try to sleep and get better.

Is this the first time this has been shown?

Other studies have also shown that those reporting less sleep were more susceptible to colds (when exposed by researchers to drops of rhinovirus, that is).

How does this work?

Sleep plays a role in our immune systems. Our immune cells, like T cells as well as neutrophils and cytokines, seem to work better when we've had sleep.

Our bodies fight infections with fevers that rise when we sleep.

Is this all sleep does?

Less sleep may also mean you do not respond to vaccines as well. This has been seen with Hepatitis B, Hepatitis A, and influenza vaccination.

Sleep likely impacts our vulnerability to many diseases. Because rhinovirus is a mild infection, scientists will purposefully infect volunteers with this cold virus, but they wouldn't do this for other infections. We can simply design good studies to show us.

Don't you sleep less or more because you're sick?

Infections do change our sleep cycles.  Some sleep less when they're sick, kept up by coughs and sneezes. Others become groggy, falling asleep early and sleeping late. People with the flu often sleep more and the infection itself leads to more sleep

Can you bank sleep? Can you play catch-up and not get sick?

These are all sorts of questions we don't fully have answers to. Most studies are only observational. It's hard to tease out whether we sleep more because the infection tires us or because we are fighting the infection; or how much sleep we've had before or after becoming sick affects us.

This study was important because it followed experimentally exposed individuals to an infection. It showed that it was primarily the amount of sleep before being exposed to an illness, rather than timing of sleep and other factors, that was important. However, for most infections, we aren't going to have scientists infecting volunteers with nasty pathogens. The common cold from rhinovirus is mild enough that we can study this, but for most infections we will need to observe, rather than experiment, to understand how sleep interacts with health.

We do know though, that if you're a Fruit Fly it's good to catch up on sleep. Getting some Z's when you're sick is a good idea. For fruit flies at least, being able to catch up on sleep might be the best thing. This holds true for fruit flies even if they're sleep deprived before they got sick. 

In one study, some fruit flies pulled 'all nighters' and others slept well. They were then all exposed to an infection. The ones who'd been up all night did better...that is, once they got some sleep. If they were sleep deprived after becoming sick, they weren't at an advantage. So maybe being a bit sleep deprived isn't that bad - as long as you have a chance to make up for it and happen to be a fruit fly.  (They also were getting sick with a very different sort of an infection - bacterial infections which usually only affect people who are already sick - like Serratia marcescens or Pseudomonas aeruginosa bacteria)

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