Just about everyone with an unobstructed nose will breathe through their nose when at rest or during casual activities, but most people will breathe through their mouth during exercise. The more intensely you exercise, the more likely that you will have to breathe through your mouth because you may not be able to get enough air through your nose to feel comfortable (Respiration Physiology, 1983;53(1):129–133).
Possible Advantages of Breathing Through Your Nose
Why would you even consider trying to control whether you breathe through your mouth or your nose? Compared to mouth breathing, nasal breathing:
• helps to filter out pollutants
• helps to filter germs
• adds moisture to the air you breathe
• heats the air you breathe
• may reduce asthma attacks in people who suffer from exercise-induced asthma.
Nasal Breathing Takes Practice
You can breathe far more air into your lungs through your mouth than you can breathe through your nose. You can exercise intensely when you breathe just through your nose, but you will need to practice (PNAS, May 19, 2015;112(20):6425-6430).
• How intensely you can exercise depends on how fast oxygen can pass from red blood cells into muscle cells.
• The cells lining your nose and sinuses release large amounts of a gas called nitric oxide while the cells lining your mouth and throat do not (Nat Med, 1995;1:370–373).
• Breathing through your nose releases far larger amounts of nitric oxide, which specifically widens the very small blood vessels next to muscles to bring the red blood cells closer to muscle cells, to increase markedly the rate that oxygen passes from red blood cells to muscle cells.
One study showed that with training, you can get enough air while breathing through your nose to exercise at up to 85 percent of your maximum capacity (Int J of Kinesiology and Sports Sci, Apr 30, 2018;6(2):22). Ten recreational runners practiced nasal breathing during exercise for six months and when they breathed through their noses while exercising at up to 85 percent of their maximal capacity, they had the same:
• time to exhaustion,
• maximal capacity to take in and use oxygen (VO2max), and
• peak lactate levels. (Lactate levels increase when you don’t get enough oxygen).
Nasal breathing brought in the same maximal amount of oxygen as mouth breathing, but nasal breathing markedly reduced:
• respiratory rate (breaths per minute), and
• ratio of oxygen intake to carbon dioxide output.
Nasal Breathing May Help with Exercise-Induced Asthma
People who have exercise-induced asthma may benefit from nasal breathing when they exercise. Within minutes after starting to exercise, they often suffer wheezing, coughing, shortness of breath, a tight chest, decreased endurance, or a sore throat. These symptoms are usually caused by breathing dry and cold air (Allergy, 2013;68:1343–1352). Practicing nasal breathing for several months can help to decrease asthma attacks (Clinical Allergy, 1981;11(5):433-9). However, nasal breathing has been shown to hinder performance of elite athletes who suffer from exercise-induced asthma (British J of Sprts Med, 2012;46:413-416).
My Recommendations
• Most people can learn to breathe comfortably through their noses during intense exercise if they want to (International J of Ex Sci, 2017;10(4):506-514), but nasal breathing is not recommended for competitive athletes since it is likely to reduce their maximum exercise intensity (Australian J of Sci and Med, 1995;(273):512-55).
• You don’t need to breathe through your nose when you exercise in very cold weather. Your nose warms the air much more than your mouth does, but exercise causes your body to produce such large amounts of heat that air taken through your mouth at 40 degrees below zero Fahrenheit during exercise will be warmed almost 100 degrees before it reaches your lungs. Breathing air that cold would burn your nose so much that you would quickly lose interest in exercising and seek shelter.
• Your nose clears pollutants far more efficiently than your mouth does, but people with healthy lungs can exercise safely using mouth-breathing on mildly polluted days. Your air tubes are lined with small hairs, called cilia, that sweep pollutants towards your mouth where you swallow them with your saliva and they pass from your body. However, breathing heavily polluted air when you exercise can damage your lungs, whether you use your mouth or your nose. Air quality experts tell us that if you can see ash or smell smoke, stay indoors with windows and doors closed.
• If you want to try nasal breathing, you may find that commercially-available nasal strips that fit over the bridge of your nose make it easier and more comfortable.
• The bottom line is that you can breathe through either your mouth or your nose during exercise. Do whatever feels most natural for you.
Gabe Mirkin, M.D., is a sports medicine doctor and fitness guru. A practicing physician for more than 50 years and a radio talk show host for 25 years, Dr. Mirkin has run more than 40 marathons and is now a serious tandem bike rider with his wife, Diana. His website is http://drmirkin.com/. Click to read Gabe’s full bio.
THE EFFECT OF NASAL BREATHING VERSUS ORAL AND ORONASAL BREATHING DURING EXERCISE: A REVIEW
http://www.conscientiabeam.com/pdf-files/phy/90/JSR-2020-7(1)-1-10.pdf
Nice review! Thanks for sharing that!
Having to ride for 6-7 weeks with a jaw wired shut, I know what it is like to be able to breath only through the nose and clenched teeth. There is no question that this limited the amount of air I could get into my lungs and therefore limited my power output. If the article referencing 85% of capacity was referring to power, I would say that was the absolute upper limit. If by “85% of capacity” it was referring to some other measure of exercise that was perhaps triggered by restricted air intake (like heart rate) then it was a reflection of using the wrong metric.
Nasal breathing during exercise is very beneficial to long-term health and fitness. Dr. John Douillard in “Body, Mind, and Sport” teaches an effective technique for integrating nasal breathing into exercise. There are a host of neuro-respiratory dynamics that have many advantages over mouth breathing. I’m not promoting Douillard, but must admit that doing nasal breathing (during cycling) for almost 30 years has had a very positive impact on my cycling performance and overall health.
The comment that “You can breathe far more air into your lungs through your mouth than you can breathe through your nose.” is true only if you are considering the total volume of air moving in and out of the airway. It does not address how the different lung fields are being ventilated in nasal breathing vs mouth breathing, nor the significant effect on ventilation/perfusion ratios in the those lung fields. Nasal breathing has the potential to oxygenate red blood cells more effectively than mouth breathing, without the sympathic nervous system stimulation that results from mouth breathing.
Interesting comment, thanks for that. I had a sports doctor once tell me that it was indeed more beneficial to breathe through your nose when exercising, but he said to exhale out of the mouth. I also heard about this method that the doc mentioned from an FBI physical fitness trainer years ago. While my information is from 30 or more years ago, it’s something I do, unless my nose gets stuffy from allergies.
Due to many sinus infections in my life, I’m now 73, I decided this year to try nose breathing to see if it helps.
I have been at it for 2 months serious and can see the difference in air intake. Time will tell if it helps sinus issues.
I ride for recreation but as of now my times are very close to last fall with mouth breathing!
Nasal breathing is much preferred over mouth breathing, especially for people with bronchospasdic disorders (aka asthma et al). It does take practice to master nasal breathing but some added benefits are reduced amount of lactic acid buildup in the muscles. I would recommend that everyone check out the work of the late Russian physician and researcher, Dr. Konstantin Buteyko who devoted his life’s work to the study of breathing disorders and the book by Patrick McKeown, “Close Your Mouth.”
Can anyone comment on breathing in through the nose and out through the mouth? In the martial art that I practice,Aikido, they teach us to breathe in through the nose and out through the mouth, ideally making the exhalations twice as long as the inhalations. Aikido can be quite demanding aerobically and anaerobically. It takes a lot of practice to breathe this way but it’s supposed to keep your mind more calm while in demanding (threatening) situations.
Cycling now with a mask on it is easy to let yourself breathe just through your mouth which can lead to a dry mouth. My dental hygienist sister-in-law says she is seeing issues in patients with chronically dry mouths. My nurse practitioner wife says that she was taught in Nursing school to breathe through her nose when masked. One reason is that it tends to keep you more calm, which is critical for patient care, but important for the rest of us too.
“Can anyone comment on breathing in through the nose and out through the mouth? ”
Sure, this is a desirable way unless you are doing a short all-out effort.
I’ve tried doing nasal only breathing while doing zone 2 rides but what I’ve found is that after a couple minutes my nose is so full of “snot” that I have to quit for a while until it clears up again. In the meantime many snot rockets are launched. Is this normal and does this get better over time?
I suspect that nasal breathing would be useful on very long rides where there is a tendency to ride too hard early and regret it later, almost as a pace regulator when not being competitive. I will try that on the Hotter N Hell 100 in Wichita Falls, TX this year. Always go out too fast trying to beat the rising heat. On a side note, mouth-taped nasal breathing at night prevents a dry mouth and protects teeth. I just use a 1/2″ x 1″ piece of quality painter’s tape vertically in the middle. Hard to yawn, sneeze, or talk, but other than that I sleep great and never get thirsty. Painter’s tape stays on and does not feel like it is peeling your skin off in the morning.
Because of my big nose with floppy side walls I use nasal strips to open up. It definitely helps me though I get many questions whether it is broken or just made fun of. I see the strips often in various sports these days.
I have done a modification where I breathe primarily through my nose but also let a bit pass over the top of my tongue with my mouth open a little which allows the benefits of nasal breathing and adds about 20% more air to pass. The snot rockets are fun to blow and a source of distraction while suffering.
I live in San Diego. It can get 100F here, with relative humidity in single digits.
When this happens, I say “It is a good day to keep your mouth shut” while pedaling. When your mouth is open, the saliva inside of your mouth evaporates. Your mouth becomes very dry and your body loses moisture.
A rule of thumb – inhale with nose, exhale with mouth.
Ditto to all those in favour of nasal breathing, except ‘perhaps’ for the most strenuous moments of workout (i.e. steep hill climbs).
As a small but significant departure, I have done a number of test rides wearing an N95 mask – a good one with leakproof seal and enough filter area as to no be restrictive. On a few of these test runs (out and back, no wind) I actually improved my average speed/time on the masked interval over the uncovered one !! So if you are in situations of high pollution, or any risk of viral contact, masking has apparently NO detrimental effect on performance, except maybe at that last 15% of full exertion. Needless to say in these Covid times I always carry a mask in my pocket in case of mishap and resultant close contact with medics or others.. But for those who feel that masks ‘suffocate’ them and interfere with their workout, whether that be in sport or at the gym, that is total nonsense.
For decades I have consciously made myself breathe through my nose for the first 1-2 miles of any running road race. I have found it to be the most effective way to keep my pace where I want it (i.e. not too fast) when I have all that adrenaline pushing me to run faster initially.