(CNN) — Life with a stuffy nose isn’t fun, but James Nestor is ready. Besides, this is for science.
While researching his book “Breath: The New Science of a Lost Art,” Nestor had Stanford University scientists plug his nostrils with silicone and surgical tape to measure the effects of breathing through the mouth for 10 days.
“We knew this wasn’t going to be positive because there’s very solid science documenting all the harmful effects of breathing through the mouth, from periodontal disease to metabolic disorders,” Nestor explains.
It was surprising how quickly the experiment affected him.
Nestor’s blood pressure rose 13 points, reaching grade 1 hypertension. Heart rate variability measurements showed his body was in a state of stress. His pulse quickened and brain fog made him dizzy.
He also snores for several hours each night and has obstructive sleep apnea. His blood oxygen levels dropped.
“We had no idea it was this serious,” Nestor said. “The snoring and sleep apnea were so severe and happened so quickly that it surprised everyone.”
Nestor learned that, in addition to the dangers of becoming a research subject, mouth breathing could ruin a good night’s sleep.
Scientists have found that mouth breathing at night increases the risk of sleep disorders such as snoring, sleep apnea and hypopnea (partial air blockage). Each of them, in turn, contributes to daytime fatigue.
This doesn’t mean you’re destined to wake up groggy because you tend to breathe through your mouth while sleeping.
Experts have a long list of strategies designed to turn you into a nasal breather, including cheap breathing techniques you can buy at the corner store.
What are the causes of mouth breathing at night?
Sleep surgeon Dr. Steven Parker says there are many reasons why people breathe through their mouths at night.
(Illustration: Max Pepper/CNN)
“The most common cause is nasal congestion,” Parker explains. “Due to allergies, or a deviated septum. Many medications can also cause nasal congestion.”
He explains that these problems are exacerbated while sleeping.
To calculate the physical and mental effects of mouth breathing, Nestor measured physiological data three times a day.
“Normally when you lie down, the blood vessels in your nose fill with blood,” he explains. If you can’t breathe easily through your nose, you may open your mouth to get air, Parker explains. This triggers a positive feedback loop.
“You might think that if you open your mouth, you’ll breathe better, but the opposite is true,” he explains. When the jaw opens, the tongue is pulled back and blocks the airway. “Even if you don’t have sleep apnea, or you have mild sleep apnea, opening your mouth can make it worse.”
How do you know if you are breathing through your mouth at night? When many people notice they breathe through their mouth, their spouse or partner tells them, Parker said.
If you wake up with a dry mouth or persistent tiredness, these may be warning signs. Another sign of sleep apnea or other sleep disorders is having to go to the bathroom multiple times each night, Parker explains. Stopping breathing puts stress on the heart, triggering the release of hormones that lead to increased urine output, Parker noted.
How to stop breathing through your mouth
When Nestor held his nose for scientific reasons, he experienced an extreme form of mouth breathing. But in retrospect, he realized that he had been waking up with a dry mouth for some time, suggesting that he had stopped breathing through his nose for at least some time.
(Illustration: Max Pepper/CNN)
If you need to breathe through your mouth at night, Parker recommends taking care of your nose first to minimize congestion.
“First, avoid eating right before bed,” she says. This is because gastric juices can reach the nose, sinuses, ears, and mouth, causing congestion and inflammation.
Parker also recommends rinsing your nasal passages with saline and using saline from a squeeze bottle to rinse your nose. “It’s a mild decongestant because the salt water draws clear water out of the membrane,” he explains. (Over-the-counter decongestant sprays may cause habituation and rebound symptoms and should be reserved for short-term use, Parker says.)
Respiratory ailments are so common that they have spawned an entire industry dedicated to unclogging your nose. Parker says some people can find relief with nasal strips (which open their nose from the outside) or nasal dilators (which widen air passages from the inside).
But even if you manage to clear your nose, breathing through your mouth at night can be a hard habit to break. Therefore, some people look for products that ensure lip closure at night.
Many experts warn against covering your mouth while sleeping.
“If you have obstructive sleep apnea, yes, it can be very dangerous,” sleep expert Dr. Raj Dasgupta, associate professor of clinical medicine at the Keck School of Medicine of USC, said in a previous CNN article.
“There is limited evidence on the benefits of oral dressings, and I would be very cautious and check with your doctor before even trying them,” Dasgupta added.
Dasgupta recommends seeing an otolaryngologist or sleep specialist for a diagnosis and treatment plan.
Jane Rose Smith is a writer living in Vermont. You can find her work at jenrosesmith.com or follow her on Twitter @jenrosesmithvt. CNN’s Sandee LaMotte also contributed to this article, which was originally published on May 14, 2023.
