Mouth breathing, snoring and apnea: why nasal breathing protects sleep

The Short Version

A functional dentist, a science journalist, a neurobiologist and a breathing coach all say the same thing: breathing through the mouth at night goes with snoring, sleep apnea and sleep that does not restore you, and breathing through the nose is the default the body is built for [1][2][3][5]. Their shared advice is to train nasal breathing while awake, because the habit tends to carry into sleep, and to treat the nose and tongue as things that can be exercised [1][2][3][4]. They also agree on the limit: severe apnea needs a doctor and often a machine, and some airways are blocked by structure that no habit will change [1][2][3][4]. That makes the airway a cause of tired mornings that the usual sleep advice about light, caffeine and wind-down does not touch [1][5]. Anyone who snores heavily, stops breathing in sleep or is sleepy all day should get a medical assessment before trying any of this alone [3].

Table of contents

What They Said

Staci Whitman: small jaws, low tongues and undiagnosed sleep problems

Dr. Staci Whitman, a functional dentist who treats children and adults, starts from the claim that humans are meant to be nasal breathers and that up to 50% of people breathe through their mouths, a figure she considers an underestimate [1]. Her explanation is anatomical and begins with food. "We used to chew four hours a day. We now chew four minutes a day." [1] Ancestral chewing helped grow wide jaws and sinuses; with softer processed food and less breastfeeding, she says, faces and jaws are shrinking [1]. She points to ancestral skulls in natural history museums in which all 32 teeth fit the dental arches [1].

The consequence for sleep follows from the geometry. When the structure shrinks, the nasal volume, sinuses and airway shrink with it, and "Our tongue has no room in our mouth anymore" [1]. The tongue either pushes forward or falls back, where it obstructs the airway [1]. She says there is a great deal of sleep-disordered breathing and sleep apnea as a result, and of that problem she says, "Now that's not getting diagnosed" [1].

She describes what she sees in children: forward head posture as they try to open the airway, dark circles under the eyes and open mouths [1]. The signs she tells parents to watch for are snoring, grinding, restless sleep, odd sleep positions and bedwetting [1]. In her account, children who are not getting into deep restorative sleep have impaired growth hormone and impaired antidiuretic hormone, and the brain's overnight clearing system does not engage [1]. She also says children with sleep-disordered breathing can show behavioral problems that get diagnosed as ADHD, and argues that screening for airway issues could avoid some of that [1]. This is her clinical view; a parent with that worry needs a proper evaluation, not a self-diagnosis [1].

She repeats a figure also used by Nestor, that nasal breathing delivers "20% more oxygen", and adds a dental cost: mouth breathing dries the mouth, and saliva is what protects and remineralizes teeth [1]. Nasal breathing also supports nitric oxide, which matters for blood vessels [1].

On treatment she separates children from adults. Most facial development is done around age 10, so in young children functional appliances can widen the palate, and because "the roof of the mouth is the floor of the nose", widening it widens the sinuses and can straighten the septum [1]. Adults are harder. She recommends myofunctional therapists: "Think of them like physical therapists for breathing", teaching lips closed and tongue up [1]. A mouth breather's tongue lies low and weakens: "If you don't use it, you lose it" [1]. But she is direct that an adult with a skeletal discrepancy usually needs some intervention: "You're not going to just be changing it through lip taping" [1]. She mentions appliances that expand the adult palate as less invasive than jaw surgery [1].

For adults considering mouth tape she gives a test: if you can breathe calmly through your nose for three minutes with your lips sealed, start taping for short periods while awake and build up to overnight [1]. Her overall ranking is plain: "the most important thing for health is how you're breathing and how you're sleeping" [1].

James Nestor: close the mouth, work the throat, know the limits

James Nestor, the journalist who wrote Breath, covers much of the same ground from interviews with researchers [2]. He puts habitual mouth breathing at somewhere between 25 and 50 percent of the population and calls the mouth a backup delivery system [2]. Air through the nose is humidified, pressurized and filtered; air through the mouth gets none of that [2]. He states the 20% oxygen advantage and attributes it to the time the breath takes, the pressure, and nitric oxide released in the sinuses [2].

Like Whitman he blames changed faces. He reports that skulls older than roughly 500 years show wide jaws and straight teeth, and that about 90% of people today have smaller mouths, crowded teeth and smaller airways [2]. He adds a second mechanism for the throat itself: modern diets are overwhelmingly soft, so the soft tissues at the back of the mouth get flabby [2]. Of couples who sleep apart because one snores or has apnea, he says, "There's nothing normal about this" [2].

His position on fixes is conditional from the first sentence. The right approach depends on where the obstruction is, and "Some people absolutely need surgery" [2]. For others he describes myofunctional therapy, exercises for the tongue and throat, and says published studies show these exercises significantly helping snoring and mild to moderate sleep apnea [2]. The host, Lewis Howes, offers his own experience: when he began sleeping with his mouth closed, "I stopped snoring" [2]. Nestor agrees in part: "for a lot of people, simply shutting their mouth at night can open the airway", but not for those whose problem is higher in the nasal passage [2].

He gives exercises. The simplest is resting posture: mouth closed, tongue on the roof of the mouth, front teeth lightly touching [2]. Another is to suction the tongue to the palate and hold; a third slides the tongue along the palate from as far back as possible [2]. He offers a quick check as well: "If you see teeth imprint on your tongue, then your mouth is too small for your tongue" [2]. For a blocked nose he describes exhaling, pinching the nostrils, nodding and shaking the head until there is a strong need to breathe, then breathing calmly through the nose, resting 45 seconds to a minute and repeating [2].

He also tried the structural route. A retainer worn at night gently widened his upper palate, and he says a scan a year later showed his airway had increased by roughly 15 to 20 percent; he adds that this worked for him and may not for others [2]. His general rule is "breathe through your nose all the time" [2]. And he marks his own authority: "I'm not a doctor. I'm not a breathing therapist." [2] He says, "Breathing isn't going to do everything for you" [2].

Andrew Huberman on breathing: daytime practice carries into the night

In his solo episode on breathing, Andrew Huberman gives the neurobiologist's version [3]. People in general, he says, tend to under-breathe at night and over-breathe during the day [3]. Under-breathing at night is sleep apnea, and its signs include snoring and daytime sleepiness combined with daytime anxiety [3]. He stresses the stakes: sleep apnea raises the risk of heart attack and stroke and is linked to sexual dysfunction, cognitive problems and worsened dementia [3].

He divides cases by severity. Severe cases may need a CPAP device and a physician's input [3]. For milder cases he describes a growing behavioral approach: training nasal breathing, including placing medical tape over the mouth at night, or nasal breathing during low-intensity exercise and daytime work [3]. His central claim is that nasal breathing practice by day tends to carry over into sleep, reducing snoring and apnea, and that unlike CPAP it trains the system to breathe properly [3]. In his conversation with Whitman he reports the same thing from his own tracking: making himself breathe through the nose during easy cardio left him with less mouth breathing and snoring at night [1].

He recommends nasal breathing as the default whenever you are not eating, speaking or exercising hard [3]. It warms and humidifies air, and it produces nitric oxide that dilates blood vessels and can relieve congestion [3]. He notes that nasal breathing feels harder but that the added resistance lets you inflate the lungs more fully, and that stuffiness alternating between nostrils is normal [3]. His check is that with mouth closed and tongue resting on the roof of the mouth, you should be able to breathe comfortably through the nose [3]. Citing the book Jaws by Stanford colleagues, he says chronic mouth breathing can lengthen and weaken facial structure, and that practicing nasal breathing, especially in children, can improve this over time [3].

Andrew Huberman on hormones: apnea as a hormone problem

His episode on testosterone and estrogen comes at the same issue from the endocrine side [4][6]. One of the behaviors most associated with low estrogen or low testosterone compared with age-matched peers, he says, is apnea [4][6]. He defines it: "Apnea is under breathing or mainly cessation of breathing during sleep" [4][6]. People hold their breath and then suddenly wake; it is common in people who are significantly overweight [4][6].

He names breathing as the first behavioral foundation for hormone health and says supplements are not worth discussing until breathing and light are right [4][6]. Nasal breathing helps hormones, in his account, "by making you a better sleeper" [4][6]. His instruction is that unless you are working out very hard, eating or speaking, "you should be a nose breather", awake and asleep [4][6].

He is the most optimistic of the group about training. For people with severe apnea, "they're going to need the CPAP machine" [4][6]. For everyone else, the way to get good at nasal breathing is to do more of it, especially during cardiovascular exercise, because "the sinuses have a capacity to dilate over time" [4][6]. His advice is to "breathe through your nose while exercising unless you're in maximum effort" [4][6].

Patrick McKeown: the stuffy nose and the stress loop

Breathing coach Patrick McKeown, in a compilation episode hosted by Mel Robbins, adds two points [5]. First, when you breathe through your mouth, breathing tends to be faster and higher in the chest, which activates a stronger fight-or-flight response [5]. Stress changes breathing, he says, but also "our everyday breathing is feeding into our stress levels" [5]. Second, he ties the nose directly to sleep: a stuffy nose makes you two to three times more likely to have sleep problems, to snore or to have obstructive sleep apnea, which then affects mental health, concentration and attention [5]. He speaks from experience as someone with asthma who mouth-breathed for years [5].

He teaches a nose-unblocking exercise close to Nestor's: a light breath in and out through the nose, pinch the nostrils, nod the head while holding the breath for around 30 seconds, then breathe in through the nose, repeated five or six times [5]. He cautions that people prone to panic or anxiety, pregnant people and those with cardiovascular issues should not do that version [5]. His evidence is modest by his own account: a pilot study of 26 people in which rhinitis symptoms fell by 70%, with the larger follow-up never done [5].

Where They Agree, and Where They Don't

The consensus. Every source treats nasal breathing as the proper default by day and night [1][2][3][4][5]. Every source links mouth breathing or a blocked nose to snoring and sleep apnea [1][2][3][5]. Whitman, Nestor and Huberman all say the habit can be trained, and all three name the tongue resting on the palate as part of it [1][2][3]. All of them say severe or structural cases need professional treatment [1][2][3][4].

They agree on a cause upstream of habit. Whitman, Nestor and Huberman each point to changed jaws and faces, and Whitman and Huberman both recommend the book Jaws [1][2][3]. Huberman notes that when that book came out some people called it pseudoscience, so this account has been contested [1].

Disagreement: how far training can go in adults. Huberman says the sinuses dilate with practice and that daytime nasal breathing reduces snoring and apnea in milder cases [3][4]. Whitman says adult bone is very hard to change through posture and habit, and that a skeletal problem needs a device or surgery [1]. Nestor sits between them: exercises help many people, but he also had his own palate widened [2]. The difference is partly about which adults each has in mind. Huberman is describing people whose nose works but is underused; Whitman is describing patients whose anatomy leaves no room [1][4].

Disagreement: the numbers. Whitman and Nestor say nasal breathing gives 20% more oxygen [1][2]. McKeown cites a single 1988 finding that continuous nasal breathing raises oxygen uptake in the blood by nearly 10% [5]. Prevalence estimates for mouth breathing also range from 25 to 50 percent or more [1][2]. None of these figures comes with study details in the sources, so treat them as rough.

Disagreement: does closing the mouth stop snoring? Howes says it did for him, and Nestor says it works for a lot of people [2]. Nestor immediately excludes obstruction higher in the nasal passage, and Whitman's warning about taping applies here too [1][2].

A gap, not a disagreement: the standard sleep advice. In the same compilation that features McKeown, sleep researcher Gina Poe gives the familiar list: morning light, daytime exercise, a warm bath at night and limited late caffeine [5]. She explains that losing deep sleep means "you will wake up with a junkie brain" [5]. Her tips act on the body clock and on falling asleep. None of them addresses an airway that narrows during the night, which is the problem the other sources describe [1][3][5]. That contrast is drawn here; the sources do not state it themselves.

Why It Works

The tongue and the airway. Whitman's mechanism is space and muscle tone: in a small mouth the tongue falls back, and in a mouth breather it lies low and weakens [1]. Nestor adds flabby soft tissue at the back of the throat [2]. Keeping the lips sealed and the tongue up holds those tissues forward, which is why both describe exercises as a workout for the mouth [1][2].

The nose can be trained. Huberman says the nasal passages dilate over time with use [4][6]. Nestor and McKeown describe breath holds that open a blocked nose, which Nestor attributes to carbon dioxide dilating blood vessels [2][5]. Huberman says nitric oxide made in the nose dilates vessels and can relieve congestion [3].

Carbon dioxide and calm. Nasal breathing is slower, and McKeown says it keeps carbon dioxide slightly higher in the blood, which helps red blood cells release oxygen to tissues [5]. Huberman's breathing episode makes the same point about carbon dioxide and oxygen release [3]. Mouth breathing, being faster and higher in the chest, pushes toward the stress response [5].

Deep sleep and hormones. Huberman's hormone account runs through sleep quality. Deep slow-wave and REM sleep support the ovaries and testes and the cells that make sex hormones [4][6]. Sleep also acts through cortisol: cholesterol can be converted into testosterone or estrogen, but under high stress it is diverted to cortisol [4][6]. Apnea fragments sleep, so it hits both routes [4][6]. Whitman describes the childhood version, with growth hormone and antidiuretic hormone impaired when deep sleep is missing [1].

Daytime carries into night. The claim that practice by day changes breathing in sleep rests on Huberman's description of a growing behavioral approach and on his own observation; the sources do not give trial numbers for it [1][3].

The evidence is uneven. Nestor reports published studies on throat exercises for snoring and mild to moderate apnea [2]. McKeown's nose-clearing study is a 26-person pilot [5]. Whitman notes that many of the disease links she cites are correlational [1]. Much of the rest is clinical experience and personal report.

Where It Applies, and Where It Doesn't

Training nasal breathing is aimed at mild cases and at people with no diagnosed disorder. Huberman says severe apnea may need CPAP and a physician, and he lists serious risks from untreated apnea [3]. Nasal breathing practice is not a substitute for that treatment, and Nestor says explicitly that nothing he reports is a reason to drop prescribed care [2].

It does not fix structure. Obstruction high in the nasal passage or a skeletal discrepancy may need surgery or an appliance [1][2].

Mouth breathing is not the only cause. Huberman notes apnea is common in people who are significantly overweight [4][6].

Mouth taping is conditional. Whitman's three-minute test comes first, and she and Huberman both describe building up gradually [1][3]. Someone who cannot breathe comfortably through the nose with lips closed should not tape their mouth shut at night, and anyone with suspected apnea should ask a clinician first [1][3]. McKeown's longer breath holds are not for people prone to panic, pregnant people or those with cardiovascular issues [5].

Mouth breathing has its place. All the sources allow it for eating, speaking and maximum-effort exercise [3][4].

For children the window is different. Whitman says most facial development is complete around age 10, so early screening by an airway-trained dentist, a myofunctional therapist, an orthodontist or an ear, nose and throat specialist matters more than it does for adults [1]. She admits that assembling that team is a lot of work for parents [1].

Ordinary sleep habits still matter. Poe's advice on light, exercise, warmth and caffeine addresses a different part of the problem, and nothing in these sources suggests dropping it [5].

What To Do With It

1. Check for the signs. In adults: snoring, daytime sleepiness with daytime anxiety, and tooth imprints along the edge of the tongue [2][3]. In children: snoring, grinding, restless sleep, odd sleep positions, bedwetting, open mouths and dark circles [1].
2. If you suspect sleep apnea, see a doctor. Severe cases may need a CPAP machine, and untreated apnea carries cardiovascular and cognitive risks [3][4].
3. Make nasal breathing your daytime default whenever you are not eating, speaking or exercising at full effort [3][4].
4. Breathe only through your nose during easy and moderate cardio. It is hard at first, and Huberman says the nasal passages open with use and the habit carries into sleep [1][3][4].
5. Hold the resting posture Nestor describes: lips closed, tongue on the roof of the mouth, front teeth lightly touching. Add his tongue exercises, suctioning the tongue to the palate and sliding it along the palate [2].
6. When your nose is blocked, try the breath-hold exercise: breathe out gently, pinch the nostrils, nod your head until you need to breathe, then breathe calmly through the nose, rest and repeat [2][5]. Skip it if you are pregnant, prone to panic or have cardiovascular issues [5].
7. Before taping your mouth at night, pass Whitman's test of three calm minutes of nasal breathing with lips sealed, then tape for short periods while awake and build up [1].
8. For a child who mouth-breathes or snores, ask for an airway assessment early, since the palate can be widened most easily before about age 10 [1].
9. If habit change does not help, ask about myofunctional therapy or a structural evaluation; do not keep adding effort to a problem that is anatomical [1][2].
10. Keep the standard sleep habits too: morning light, daytime movement, a warm bath and less late caffeine [5].

Sources

1. Dr. Staci Whitman on the Oral Microbiome, Nasal Breathing, Fluoride, and Whole-Body Health · Huberman Lab
2. The Truth About Breathing: Why You're Doing It Wrong with James Nestor · The School of Greatness
3. How to Breathe Correctly for Optimal Health, Mood, Learning & Performance · Huberman Lab
4. The Science of How to Optimize Testosterone & Estrogen · Huberman Lab
5. Mel Robbins on the Three Pillars of Health: Breathing, Walking and Sleep, with Patrick McKeown, Shane O'Mara, Gina Poe and Neha Sangwan · The Mel Robbins Podcast
6. How to Optimize Testosterone & Estrogen | Huberman Lab Essentials · Huberman Lab