For the study, researchers followed 141 people for five years, checking in on them every year. At each check-in, they measured how lonely the people felt and took blood samples to look at genes involves with immunity and bodily inflammation, as well as levels of the hormone norepinephrine (one of the two major signals that happens during the flight-or-fight response).
What they found: When people felt lonely, they had significantly higher norepinephrine levels in their blood.
While that just sounds like an interesting factoid, it actually has big implications.
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When norepinephrine is shooting through your body, it slows your body’s ability to fight off viruses, making you more susceptible to getting a viral illness.
Researchers say loneliness also causes genes that make our bodies sensitive to the stress hormone cortisol to shut down, increasing our body’s inflammation response as a result. (Bodily inflammation is okay here and there, but chronic inflammation is linked to a slew of diseases like cancer and depression.)
It’s important to keep in mind, though, that this was a pretty small group of people involved in the study. The bottom line: Being on your own is totally great sometimes, but feeling lonely could have bigger implications than you’d think.
So you could stay home over the holidays and fly through old episodes of Gilmore Girls while lounging on your couch—or you could do your health (and your parents) a solid and spend it with family. Your call.