If changing your bed sheets is at the bottom of your household chore list (you know, right along with matching socks and scrubbing the shower’s grout), consider this: The skin cells that you shed in a day can feed 1 million dust mites.
Let’s repeat that. One million dust mites can feast on the dead skin cells you produce in a mere day. Disgusted yet?
The average person sheds a gram and a half of these keratinocytes (largely made up of the protein keratin) daily, says Cleveland Clinic dermatologist Alok Vij, MD. Visually speaking, that’s roughly 3/8ths of a teaspoon.
“A lot of that happens when you’re making that contact with your sheets in your bed at night,” Dr. Vij says. “Any kind of friction will abrade, or chafe, off the outer layer of your skin cells.”
Mix in hot temperatures and you’ve got an even bigger problem. Dr. Vij says you should typically wash your sheets at least twice a month as a good rule of thumb. “But as the weather gets warmer — especially if you sweat more at night — you have to really ramp up to at least once a week,” he says.
The nitty gritty (and extremely gross) details
As if simply rolling around in your own discarded skin isn’t enough, Dr. Vij says those skin cells (along with the oil and sweat from your skin, and even saliva!) can be a breeding ground for bacteria and dust mites that live on your sheets, mattress and pillows.
Dust mites don’t technically bother everyone. That is, if you don’t mind terribly sharing your sleeping spot with these eight-legged relatives of the spider who are too small to be seen by the naked eye.
But, Dr. Vij says, many people in the U.S. are allergic to dust mites, which live on every continent on Earth except Antarctica.
“That can lead to itching, trigger asthma flare-ups, other seasonal allergies or rashes if too many of them come in contact with your body,” he explains.
And what about bacteria? “Bacteria love the skin,” Dr. Vij says. “There are more bacterial organisms in our bodies than our own cells — and the skin’s one of the most commonly inhabited areas. When you let the dead skin cells rest in your sheets, those bacteria can thrive. If they get back on to your skin it can lead to folliculitis, or maybe make your eczema worse.”
Eczema, he explains, is one of the most common types of skin rashes, affecting young infants to the elderly and those everywhere in between.
“We know now that eczema is driven by a combination of the dryness of your skin and overactive bacterial colonies on your skin,” Dr. Vij says. “So by allowing those bacteria to live in harmony on your sheets and get on your skin when you hop in bed, you could be making your eczema worse — or allowing it to start in the first place.”
And now, the good news …
The risk of getting a bad bacterial infection under your skin is pretty low, Dr. Vij says. But it’s still a good idea to practice good bed linen hygiene so your own bacterial ecosystem doesn’t get out of wack.
You can certainly use this as an excuse to not make your bed (at least right away!) in the morning. Not pulling up your comforter ASAP, Dr. Vij says, gives sweaty sheets a chance to dry and reduces the moisture that dust mites and bacteria need to proliferate.
Second bonus? Take comfort in the fact that your other bedding isn’t as high maintenance as your begging-to-be washed sheets.
“Blankets and pillows don’t need to be washed as frequently,” Dr. Vij says. “But skin cells, bacteria, dust mites can definitely travel and live on your pillow or in your blanket. So at least every six months, they need to be washed.”
And don’t think of it as a bad chore. It has a substantial upside: “The washing process can actually fluff your pillow and make your blanket’s filling — down or whatever material’s inside — distributed more evenly. That’s helpful for making your pillows and blankets as comfortable as possible for their whole life.”
One last icky side-note
There’s one other reason, besides summer, why you might want to wash your sheets more often than twice a month, Dr. Vij says. It’s a furry, four-legged reason.
“Pets are common harbors for fungal organisms that can come in contact with your skin,” he says. “This can cause simple infections like ringworm, but can also lead to more aggressive infestations like scabies, which is caused by mites that can live on dogs and be transmitted to humans.
“There’s a number of other parasites, too, that can be transferred from pet to Pet Mom or Pet Dad, so make sure you’re washing your sheets often,” Dr. Vij concludes.