A Better Immune System, in Your Sleep
Welcome back to our Sleep Series, a string of blog posts about the role of sleep in our lives, including the benefits of achieving enough slumber and tips to help make it happen. As life grows increasingly stressful and complicated, it becomes more and more important to perform the necessary steps to take care of yourself, sleep being key among them.
For a long time, it occupied a place similar to an old wives' tale: if you don't sleep enough, you'll get sick. These days, we know that while you sleep, your body is charging up its line of defense against hostile invaders. Of course, no amount of sleep by itself can safeguard a person against ever getting sick. Still, the science is clear that it does make a difference, and every little bit helps.
In 2017, researchers gathered blood samples from 11 sets of twins with mismatched sleep patterns. The twin with the shorter sleep cycle had a noticeably weaker immune system. "What we show is that the immune system functions best when it gets enough sleep," said the study's lead author, Dr. Nathaniel Watson. "Seven or more hours of sleep is recommended for optimal health."
We may not yet understand every mechanism that ties sleep with better overall health, but we do know a few. As the National Sleep Foundation explains, when you're asleep, your system both creates and releases cytokines, proteins that target infection and inflammation, and thus play a key role in immune response. Less sleep means fewer cytokines, and fewer cytokines mean a less responsive immune system.
There's also the matter of T cells. These are a type of immune cell that fights against pathogens, including cells infected with viruses. To do their job, T cells need to activate special molecules called integrins, which make direct contact with foreign invaders. Once the integrins are in place, T cells can attach themselves to, and neutralize, these pathogens. Not surprisingly, integrins perform best when they're as sticky as possible.
Stress hormones adrenaline and noradrenaline impede this stickiness. These hormones are at much lower levels when you sleep, which seems to allow the integrins to become more sticky. In one experiment, researchers compared T cells from two groups of healthy people: a group who had slept and a group who had not. The people who had slept showed more integrin activation in their T cells.
Experts recommend at least seven hours of sleep a night for adults. However, according to the Center of Disease Control and Prevention, over a third of U.S. adults don't meet that bar. So if you're looking for a way to beef up your immune system, make sure you aren't skimping on your body's rest and recovery mode. Your health will thank you.