Remember when you were a kid and concerned adults told you not to go outside in winter without a hat or scarf, otherwise you’d catch a cold? In a way — though not in the way they thought — they were kind of right.
While cold weather doesn’t cause illness (it’s more likely to cause hypothermia), it is true that you’re more likely to get a cold or the flu in the wintertime.
Being indoors, dry air and traveling lead to illness
So, why exactly do more people get sick in the winter? There are several reasons.
While cold air won’t give you a cold or the flu, heated indoor air can certainly put you at risk. Breathing in heated air dries out your nose and makes it a better breeding ground for viruses.
“Viruses can reproduce 100 times better in heated air than if there’s moisture and humidity in the air,” says Dr. Havilah DeBell, an urgent care doctor at the UW Neighborhood Shoreline Clinic.
Even though Pacific Northwest winters tend to be rainy, that outside humidity doesn’t change the fact that inside we have heaters on all the time.
Other things that contribute to wintertime sickness rates are being indoors more and traveling more.
When everyone clusters together indoors to stay warm and avoid bad weather, we’re all standing within sneezing or coughing distance (the flu can travel up to six feet). We’re also touching the same surfaces that everyone else touched.
“Bacteria and viruses can live on a surface and in the air, so by sharing indoor space there’s much more exposure,” DeBell explains.
This effect is ramped up even more in places like airports, where there are people — and their germs — from all over the country and world.
“Within 6 hours you can take the flu from Louisiana and land it in Seattle,” DeBell says.
She’s not just making that up. All of the flu patients she’s seen so far this year seemingly got sick because of traveling — including a person who was returning to Seattle from Louisiana, an airline pilot and someone who had recently traveled internationally.
As for the infamous “winter vomiting bug” — aka norovirus — research hasn’t confirmed that it’s more common in winter, but DeBell wouldn’t be surprised if it is.
“There is a theory about norovirus similar to why colds and flus are more common, that because people are indoors, they’re exposed more readily,” she says.
Unlike flu, norovirus isn’t spread through the air, but it can be spread by touching infected surfaces. (Try not to think about why that is unless you want to seriously gross yourself out.)
Chronic conditions can worsen in winter, too
The one exception to the cold-air-makes-you-sick myth is for people who have a medical condition like asthma or chronic obstructive pulmonary disease (COPD).
“Breathing in cold air can irritate the lungs and cause muscle spasms for people with asthma and COPD,” DeBell says.
This can make an asthma attack or breathing problem more likely to occur.
People with these conditions are also more likely to get a cold or flu during winter, just like everyone else — except, for them, the illness might be worse because it might exacerbate their existing condition.
Dry, cold air in the winter can also affect the skin and make eczema more common.
“People could also get patches of eczema in winter even if they don’t have it any other time,” DeBell says.
How to stay healthy in the winter
While you can’t entirely prevent getting sick during the winter, there are things you can do to make illness less likely.
Get outside and exercise
Unless you have asthma, COPD or a similar condition, getting outside in cold weather (even if it’s dreary) is actually a good thing, especially if you’re adding some exercise to it.
“The more time you spend outside, the less time you’ll have to get sick because you’ll get humidified air,” DeBell says.
Wash your hands regularly
You’re probably sick of being told that you should wash your hands, but it’s true. Most people don’t wash their hands enough or for long enough (we’re looking at you, people who spread norovirus).
To get the full benefit from handwashing, you need to scrub thoroughly for 20 seconds. You can also use an alcohol-based hand sanitizer, but DeBell cautions against using antibacterial soap or hand sanitizer.
“It’s harmful to the environment, animals and people. It can be an endocrine disrupter, which means it can trigger illnesses and chronic diseases,” she says.
Instead, opt for plainer soaps and focus more on how long you’re washing for than what you’re washing with.
For extra protection, try wearing gloves; they’ll act as a barrier between your hands and any potentially virus-contaminated surfaces like door handles. Gloves can also be helpful for people who deal with eczema.
Use a humidifier
To combat dry indoor air, try using a humidifier, which will add moisture back into the air.
If you live in a house or a space with several large rooms, adding humidity to the air everywhere might be challenging. DeBell recommends focusing on your bedroom by placing a humidifier on your bedside table. That way, you’ll breathe in the damp air while you sleep.
If, like most Pacific Northwesterners, you’re concerned about mold, rest assured that your humidifier probably won’t mold, especially if you make a point of popping the top off and letting it dry out on a regular basis, DeBell says.
You don’t need a fancy humidifier; find a cool air humidifier that’s within your budget and give it a try.
Additionally, if you have eczema and notice your skin is still dry all the time, try rubbing Vaseline or a natural oil into your skin to keep it extra moisturized.
Take a zinc supplement
There are lots of anti-cold products out there that claim they’ll keep you healthy. Most of these claims are unproven, DeBell says, though if you already use a particular product and feel like it’s helpful, there’s probably no harm in taking it.
The one supplement you can take that will help you stay healthy? Zinc.
“It has been proven to shorten the course of a respiratory illness,” she says.
You can take a zinc supplement in various formulations like a lozenge or tablet. If you want to get zinc through diet alone — well, hopefully you like oysters, because they’re full of zinc. If not, maybe just stick to the supplement.
If you get sick, stay home
If you do wind up with a sore throat and runny nose sometime this winter, the best thing you can do for yourself is rest up.
Keep your nasal passages from drying out by using saline nasal spray and a humidifier. Take Tylenol or ibuprofen to help with fever or headache. Take cough medicine or even honey, which has been proven to be just as helpful with a sore throat, DeBell says.
Most of the time you have to just let the illness run its course — then it will go away on its own. It’s better not to go to your doctor or urgent care unless you’re actively getting worse or have more concerning symptoms, DeBell says.
“I always worry someone will come in with a mild cold and then leave with the flu or norovirus because they’re in the waiting area,” she says.
That goes both ways, too. The more you go out in public, the likelier it is that you’ll spread your sick germs to other people. So do yourself (and everyone else) a favor by staying home and resting.
Editor’s note: This article originally stated that zinc helps prevent colds. It was corrected on January 13, 2020 to clarify that zinc helps shorten the duration of a cold, not prevent it.