You know the feeling: you fall asleep feeling fine - good, even - and wake up with the sense that it’ll take a crane to get you out of bed. Everything hurts in the morning, and it’s not just because you slept in a wonky position or on a lousy pillow.
Turns out, our bodies seem to suppress inflammation when we sleep, leading to worse pain when we wake up and the inflammation is, so to speak, turned back “on,” according to a new University of Manchester study published in the journal of the Federation of American Societies for Experimental Biology.
The researchers examined human and mice cells with the inflammatory disease rheumatoid arthritis. Patients with RA have long known that their symptoms can vary throughout the day, with many afflicted with greater joint stiffness upon waking. But little is known about how our circadian rhythms - our inner clocks that tell us when to go to bed and when to get up - control this swinging pendulum of pain. The researchers wanted to figure that out.
What they found was that when mice were exposed to constant light, their paws were more swollen and there were higher levels of some markers of inflammation in their blood. In darkness, those inflammatory markers decreased. “At nighttime, those inflammatory markers go down but gradually rise up again in the morning,” says University of Manchester researcher and study author Julie Gibbs, PhD. She cautions that this particular study didn’t examine pain, but if you were to assume that with greater inflammation comes more pain, “you would expect more inflammation in the joints and increased pain levels in the morning,” she says.
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Very specific proteins in our cells govern the ticking of our circadian clocks, Gibbs explains, and it seems that one of the proteins involved in our inner clockwork, called cryptochrome, also influences inflammation. With more research, she believes experts might be able to predict at what time of day anti-inflammatory medication might be most helpful or even develop treatments that could target this protein to reduce inflammation, although that’s still a long way off, she says.
In the meantime, knowing that your circadian rhythm affects pain, the easiest thing to do is work with yours instead of against it, especially if you already deal with ongoing joint pain. “We know in general having a healthy circadian rhythm is beneficial,” Gibbs says. Yep, you guessed it: get yourself on a regular sleep schedule, and stay there. Keep your bedtime and your wake-up time as consistent as you can, even at weekends.
And if you tend to go on early morning runs, give yourself a little more time to warm up or consider switching to lunch runs instead.
A version of this article originally appeared on Prevention.