Like all fashion accessories, beards tend to rise and fall in popularity as social ideals shift. Lumberjack-esque millennials followed the metrosexuals of yesteryear much as how, in mid-1800s England, the ideal of the rugged outdoorsman replaced the image of the clean-shaved gentlemen. But as medical historian Alun Withey writes on his blog, the Victorian resurgence of the big, bushy beard had to do with more than just fashion.

“By 1850,” writes Withey, “doctors were beginning to encourage men to wear beards as a means of warding off illness.”

As Oldstone-Moore points out, the Victorian obsession with air quality saw the beard promoted as a sort of filter. A thick beard, it was reasoned, would capture the impurities before they could get inside the body. Others saw it as a means of relaxing the throat, especially for those whose work involved public speaking. Some doctors were even recommending that men grew beards to avoid sore throats.

The idea of beardliness as a medical remedy seems sort of ridculous, but put in context it actually makes a fair bit of sense.

The mid-19th century had a lot going on, medically: the germ theory of disease was slowly gaining ground, and with it the understanding that illness could come from wee beasties. In England, the mid-1800s was also a particularly bad time for air pollution says the EPA:

By the 1800s, more than a million London residents were burning soft-coal, and winter "fogs" became more than a nuisance. An 1873 coal-smoke saturated fog, thicker and more persistent than natural fog, hovered over the city of days. As we now know from subsequent epidemiological findings, the fog caused 268 deaths from bronchitis. Another fog in 1879 lasted from November to March, four long months of sunshineless gloom.

That people might consider a beard a helpful filter against airborne ailments doesn't seem so ludicrous.

The reality, of course, says Lauren Friedman for Business Insider, is that beards are more a medical risk than a cure:

One recent study in Behavioral Ecology points out that "hair on the face and body are potential localized breeding sites for disease-carrying ectoparasites." And a London dermatologist told The Guardian that since "facial hair is more likely to trap bacteria and food... there is actually more chance of infection with a beard than a clean-shaven face."

Then again, modern medicine and antibiotics are things that exists (for now, anyway), so we wouldn't worry too much about the health effects of your chin muffler.

H/T Melissa Dahl / NY Mag