When you’re stuffed up and miserable, sometimes it seems that for a little while, your right nostril is clear. No, wait, it’s the left. But you swore it was the right one a little while ago. It’s not just you: Sometimes one nostril feels way more clogged than the other, and there’s a scientific reason behind it.

Credit a physiological response called the nasal cycle, a process where your nostrils take turns sucking in more air, says Rachel Roditi, M.D., a surgeon in the division of otolaryngology at Brigham and Women’s Hospital.

“Our noses have a natural cycle such that we are breathing through only one side at any given moment, and this alternates every few hours,” explains Urjeet Patel, M.D., chair of the division of otolaryngology at Cook County Health in Chicago. When we’re sick and have nasal congestion, we tend to notice the obstruction much more, he says.

Here’s why your nostrils play tag team—and what you can do when one side’s all jammed up.

Why One Nostril Gets More Congested

Structures in both sides of your nose called inferior turbinates are responsible for warming and humidifying air before it reaches your lungs, says Dr. Roditi. This protects your lungs by reducing dryness and irritation.

That process is a lot of work. So your nose funnels its resources more to one side than the other to make the process more efficient.

It sends more blood flow to one nostril, which warms the air coming in through there, but also causes the turbinate on that side to swell. “That larger turbinate also functions better to humidify the air that you’re breathing,” says Jose Ting, M.D., an otolaryngologist at Texas ENT & Allergy in College Station, Texas.

That swelling means there’s less room for air to make its way in. It’s pretty subtle, though—unless you have a cold, infection, allergies, or a structural problem like a deviated septum, you probably won’t notice it going on.

But when you are sick, blood flow to your nose increases even more, sparking more swelling and greater mucus production in your nasal region, says Dr. Roditi.

Even though you’re congested throughout your entire nose, you feel it more strongly in the one nostril where the turbinate is already swollen as part of the normal nasal cycle.

“It’s also very common for patients to experience more congestion on the side of the nose that they are laying on when they are reclined, as venous congestion [blood backing up in the veins because it’s working against gravity] will cause minor enlargement of the inferior turbinates,” says Dr. Ting.

How to Treat Your Congestion

There’s really nothing you can do to shut off the nasal cycle, says Dr. Roditi. It’s likely that one nostril will always feel more stuffed up than the other when you’re sick. It’s not always the same one, of course: After about 90 minutes to 4 hours, your nose switches sides. When that occurs, you’ll probably feel some relief when the swelling in the one nostril goes down—but then the other side will start to feel clogged instead.

Your best bet is to work on easing the congestion overall. Steam from a hot shower or humidifier can help open the floodgates, says Dr. Roditi.

Drinking hot liquids can increase the rate at which the little hairs in your nose sweep mucus out of it. Some experts think that’s the mechanism by which chicken soup could help your congestion clear up.

Nasal decongestants and salt water nasal rinses or sprays are very helpful for flushing out mucus when you’re sick or just very congested, Dr. Patel adds. “Saline sprays are a great solution,” explains Lakiea Wright, M.D., an allergist at Brigham and Women’s Hospital. “You’re essentially helping your body wash out allergens or viruses,” she says. “Two other popular ways to do that are with a neti pot, or with a squeeze bottle kit from the drugstore,” she explains. Both are ways to rinse the nasal passages with saline and distilled water. Most people use the neti pot with their heads tilted over the sink, “and some people like to use the squeeze bottle in the shower,” Dr. Wright says. “Either way, they’re very effective.”

Just be aware that saline rinses can do their jobs too well sometimes. “They can make the lining tissue too dry by washing away the mucus layer, much like licking chapped lips makes them dryer,” says John D. Burgoyne, M.D., an otolaryngologist at Austin ENT & Allergy in Austin, Texas. “Make sure and back off on irrigation if you have dryness or bleeding.”

What about classic nose drops (medicated ones containing oxymetazoline)? Only use them as a last resort. “These sprays can cause rebound congestion,” says Jonathan A. Bernstein, M.D., an associate professor at the University of Cincinnati and editor-in-chief of the Journal of Asthma. They clear congestion for a while, but when the effect wears off, stuffiness rebounds right away, so you need another dose in a never-ending cycle. It’s like your nose becomes addicted to them, and relies on them to open up. If you must use these sprays, stick to two puffs a day for no more than five to seven days, he says.

“The one time that oxymetazoline drops can be very helpful is if you have to fly when your nose is stuffy from allergies,” adds Dr. Burgoyne. “Spraying the nose prior to takeoff and again as the plane starts to descend will minimize the chances that your sinuses or ears will become blocked.”

If your stuffed-up symptoms persist beyond 10 to 14 days, or you notice nasal congestion at times other than when you’re sick, check in with your doctor to make sure that something bigger—like a deviated septum—isn’t at play, says Dr. Roditi. And if your symptoms include facial pain or thick, colored mucus, check in with a doctor, adds Dr. Burgoyne.

Also consider that you might not have a cold at all; it might be seasonal allergies. Here’s how to know the difference between colds and allergies. To clear congestion in the case of allergies, you’d want to find the root of the problem—work with a doctor to find out exactly what is making you sneeze. Then you can strategize on how to avoid the allergen and also see if you need something like an antihistamine or a nasal steroid spray.

Finally, if you’ve tried everything and your nose is still stuffy and is compromising the quality of your life, ask a doctor about non-surgical treatments for inferior turbinate enlargement or other issues that might be behind your chronic half-stuffiness, says Paul Schalch Lepe, M.D., a board-certified otolaryngologist and sleep medicine specialist with Silenso Clinic and UC San Diego Health.

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Freelance Writer

Cassie Shortsleeve is a skilled freelance writer and editor with almost a decade of experience reporting on all things health, fitness, and travel. A former Shape and Men’s Health editor, her work has also been published in Women’s Health, SELF, Runner’s World, Men’s Journal, CNTraveler.com, and other national print and digital publications. When she’s not writing, you’ll find her drinking coffee or running around her hometown of Boston.

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Marty Munson, currently the health director of Men’s Health, has been a health editor at properties including Marie Claire, Prevention, Shape and RealAge. She’s also certified as a swim and triathlon coach.

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Contributing Writer

Emilia Benton is a Houston-based freelance writer and editor. In addition to Runner’s World, she has contributed health, fitness and wellness content to Women’s Health, SELF, Prevention, Healthline, and the Houston Chronicle, among other publications. She is also an 11-time marathoner, a USATF Level 1-certified running coach, and an avid traveler.