Nose Breathing vs. Mouth Breathing: Which Is Better?

“Mouth-breather” is typically used as an insult, playing on the idea that breathing mainly through your mouth makes you look less intelligent. But looks aside, as long as you’re getting oxygen to your blood and exhaling waste, does it really matter whether it happens through your nose or mouth?

The nose and mouth both provide air passageways to your lungs, but there is a reason why most people naturally breathe through their noses, says Shawn Nasseri, MD, an otorhinolaryngologist and ear, nose, and throat surgeon in Beverly Hills, California. The body’s first choice for respiration is the nose, but when air cannot freely pass through your nose, your body resorts to the mouth to receive oxygen, he adds.

(Related: Why You’re Probably Breathing the Wrong Way)

Nasal breathing offers advantages over mouth breathing

“The nose is the key breathing method, as it produces nitric oxide, which improves your lung’s ability to absorb oxygen,” Dr. Nasseri says. Nitric oxide is only produced in small amounts when you breathe in through your nose, but it’s vital in many biological processes, including regulating immunity, blood pressure, neurotransmission, and homeostasis—keeping the body in balance. The human nose has evolved to provide three critical breathing benefits, Dr. Nasseri says. Mouth breathing doesn’t offer the same advantages.

Filtration

When you breathe through your nose, it filters out many pathogens (like bad bacteria, viruses, and fungi), allergens (like pollen, pet dander, and dust mites), and air pollutants (like dust, debris, and aerosols).

Temperature control

As you inhale through your nose, it adjusts the temperature of the air before it reaches your lungs. This helps conserve energy and your body’s heat. Lungs that are too cold or too hot have a much harder time doing their job and require extra energy from your body.

Humidity

Moist lungs are happy and healthy lungs, and nasal breathing preserves moisture in the air you inhale. Mouth breathing forces your body to work harder and use more water to get the air to a suitable moisture level. “When you bypass all of that by breathing through your mouth, your lungs have a much more challenging time getting oxygen from the air and releasing carbon dioxide from [the body],” Dr. Nasseri says. “To operate at their best, lungs require clean, moist, body-temperature air.”

Nasal breathing has mental and physical benefits

Aside from making it easier for your lungs to get the filtered, humid, and right-temperature air it needs, breathing through your nose offers some other key benefits.

Reduced stress

“The No. 1 tool, bar none, in my stress and anxiety control toolbox is the ancient tactic of prana breath,” says Ben Greenfield, an exercise physiologist, human performance coach, former elite competitive triathlete, and author of 17 fitness books. “I think the best solutions are free, and there’s nothing like breath work to enhance one’s ability to be able to manage the common fight-and-flight stress response.”

You might think the act of breathing helps reduce stress, but there’s something special about nose breathing. It stimulates your vagus nerve, says Greenfield, who uses various breathing techniques on himself and when training elite athletes. The vagus nerve is the longest nerve in your body. It starts at your brain stem and extends all the way to your lower abdomen. Among other responsibilities, it regulates your parasympathetic nervous system, the body’s “rest and digest” response. So stimulating it helps you feel relaxed and calm.

Lowered risk of mental and physical illness

Lowering your stress levels is one of the best things you can do to improve your long-term health, as chronic stress causes a cascade of mental and physical problems. “Promising research has shown that stimulating the vagus nerve may help lower blood pressure, reduce feelings of depression and anxiety, decrease inflammation, and help protect against some chronic diseases. And all without the use of pharmaceuticals,” Greenfield says.

Improved memory

Breathing through your nose may also boost your memory. Nasal breathing leads to an improved ability to store and process new “episodic” memories, according to a 2018 study published in the Journal of Neuroscience.

Problems with mouth breathing

Mouth breathing is certainly better than not breathing, and for people with blocked sinuses, severe allergies, or anatomical issues like a deviated septum, it may be the only option. Yet breathing primarily through your mouth can cause physical, medical, emotional, and social problems, Dr. Nasseri says. “Chronic mouth breathing throughout the day and night can cause altered levels of carbon dioxide and oxygen in the bloodstream, leading to problems throughout the body,” he says.

Sleep apnea

Mouth breathing and sleep apnea, a common sleep disorder involving irregular breathing, can become a vicious cycle, Dr. Nasseri says. Sleep apnea can cause you to breathe through your mouth, and mouth breathing can cause sleep apnea. The condition is associated with a host of health issues, including weight gain, heart disease, and depression.

Sore throat

If you breathe through your mouth, you’ll have a drier mouth and throat, which can leave it feeling irritated or painful. (Try some of these sore throat remedies.)

Fatigue

Even if you don’t have sleep apnea, mouth breathing at night leads to lower-quality sleep and less sleep overall, according to a 2011 study published in Sleep Medicine Reviews.

Brain fog

Whether it’s due to not getting enough sleep or from an imbalance of oxygen and carbon dioxide in the blood, mouth breathing can leave you feeling mentally fuzzy and forgetful.

More allergies and asthma

People with existing respiratory conditions, like allergies and asthma, will see a worsening of their symptoms when they breathe through their mouth. Unfortunately, these conditions often make it harder to breathe through the nose, thanks to nasal congestion. This can turn into a vicious cycle.

Effects on oral health

Mouth breathing can have profound effects on your oral health, which in turn affects your overall health and well-being, says Brian Harris, DDS, a dentist practicing in Scottsdale, Arizona, and host of “The Virtual Dentist” podcast. “Mouth breathing can dry out the teeth and oral tissues, leading to problems with your teeth and mouth,” he says. “Saliva hydrates the teeth and oral tissues, helping to prevent these issues.” If you breathe through your mouth, it’s important to let your dentist know. Dentists are sometimes able to help prevent oral side effects of mouth breathing, and they recommend getting an early start on treatments for any negative consequences. Some of the effects of a dry mouth from mouth breathing include:

Tooth decay

“Mouth breathers tend to accumulate more plaque on the teeth and have increased levels of Streptococcus mutans, the bacteria that cause tooth decay,” Dr. Harris says. This decay can lead to tooth pain and sensitivity, cavities, cracked and broken teeth, infections, and abscesses, not to mention the pain of all the expensive dental work needed to correct these problems.

Tooth sensitivity

Saliva protects your teeth by cleaning off bacteria. When your mouth is too dry, those bacteria can accumulate around your gum line, causing it to recess and exposing the roots of your teeth. Exposed roots cause sensitivity. In addition, air on exposed roots can trigger or worsen tooth sensitivity.

Mouth pain

Saliva also keeps the inside of your mouth moist. When those oral tissues dry out, they can become raw and painful. Dry mouth increases your risk of gingivitis (inflamed gum tissue) and oral sores, both of which can be very painful, Dr. Harris says.

Infected gums

Untreated gum and tooth decay can progress to periodontal disease, an infection of your gum tissue. It causes swollen, painful, red, bleeding, and recessed gum tissue. If it progresses, it can become quite serious, requiring invasive treatments or surgery. Periodontitis also increases your risk of a heart attack.

Bad breath

No one wants to spew noxious odors from their mouth, and dry mouth is one of the leading causes of halitosis, or bad breath, Dr. Harris says.

The one time mouth breathing may be better

“Nasal breathing” is a big trend in fitness circles these days, with proponents suggesting it can increase your cardiovascular fitness more than if you did the same workout breathing through your mouth. But if you’ve ever tried to make it through a hard cardio workout without gasping for air through your mouth, you’ll understand how difficult that can be. The science on this issue is mixed.

The main benefit of mouth breathing is that it lets you “exchange air” faster. People who breathed only through their noses during a tough cycle workout showed higher heart rates—a sign of cardiovascular stress—than cyclists breathing solely through their mouths, according to a 2017 study published in the International Journal of Exercise Science. The researchers noted that the nine athletes were able to perform at the same power and intensity regardless of breathing style, however.

A separate study, published in 2018 in the International Journal of Kinesiology and Sports Science, came to a different conclusion. For six months, researchers followed 10 runners who only used nasal breathing during their workouts. They found the runners had a lower breath rate yet the same blood oxygenation levels as when they breathed through their mouths. The researchers concluded this allowed oxygen to get to the blood more efficiently, meaning the runners’ bodies needed to work less to achieve the same result.

Thankfully, breathing during exercise is not an all-or-nothing proposition. Ultimately, do whatever feels best to you during your workout, and that will likely be a mix of nose and mouth breathing.

Treating mouth breathing

Mouth breathing is treated based on the underlying cause, which can be anatomical, environmental, or from an underlying health condition. It’s important to talk to a doctor about what is causing your mouth breathing and what you can do to resolve it. Most causes of mouth breathing lead to an obstructed or partially blocked nasal airway, which forces the body to breathe through the mouth, Dr. Nasseri says. You have several options to help alleviate this while you work on treating the underlying cause:

Nasal spray

The daily use of a sterile saline spray will help keep the nasal passageway moist and clean.

Medications

Depending on the severity of the nasal congestion, there are decongestants, antihistamines, and steroid sprays that can be used to open up that airway. These should only be used temporarily, however, as they can worsen the problem if overused.

Nasal strips

These plastic or fabric strips physically hold open your nostrils, helping to open up your airway.

Nasal surgery

In more serious cases, where there is a physical malformation, you may need surgery to straighten the nasal wall, fix a deviated septum, or trim the nasal filters (turbinates), allowing you to breathe more easily.

Other surgery

Your throat and sinuses also play a big part in how you breathe, and you may need surgery to correct anatomical problems or to remove obstructions, like enlarged tonsils.

Bottom line

Breathing through your nose is preferable in most situations, so if you are a chronic mouth breather, talk to your doctor about how to resolve this common and frustrating issue.

Next: 6 Breathing Exercises for Anxiety That Can Help You Feel Calmer