CLOSE THE MOUTH
Why a closed mouth plays such a big role in healthy baby and toddler sleep
We are all meant to sleep with our mouths closed, breathing easily through our noses. Our lips should be gently sealed and our tongues suctioned to the roof of our mouths. If your baby or toddler is sleeping with their mouth open – even if they're breathing through their nose – we need to figure out why.
Breathing through the nose
Breathing through our nose is really different than breathing through our mouth. Our nose contains small hair-like structures called cilia, which act as a filtration system that helps clean the air coming in and prevent any pathogens from getting into the respiratory tract. Our nose also has tiny structures called turbinates that heat and humidify the air as it passes through our nasal cavity.
But our mouth doesn't have either of these functions. This means that the air we breathe in through our mouths isn’t purified in the same way as when we breathe in through our noses.
Furthermore, a gas called nitric oxide is released when we breathe in our nose. Nitric oxide helps to widen blood vessels, which helps to improve oxygen circulation. Studies on rats show that when access to nitric oxide is compromised, it impacts sleep: Wakes increase and slow-wave (deep) sleep decreases (Monti et al., 2004).
When we sleep with our mouth closed, our tongue stimulates the roof of our mouth, where the vagus nerve system begins. This stimulation helps our nervous system enter into a parasympathetic state (rest and digest) and we feel calm. When we sleep with our mouth open, we don't have this vagus nerve stimulation, which can cause us to get stuck in “fight or flight” mode.
Is it okay to sleep with the mouth open?
Many parents ask me if sleeping with the mouth open is okay if their child is still breathing through their nose. My answer is no. (With the exception being if they're sick or congested.)
It's a lot harder to breathe through your nose when your mouth is open. (Try it!) So even if your child is breathing through their nose now, chances are good they'll switch to mouth breathing over time if nasal breathing takes more effort to maintain.
Causes and risks of mouth breathing at bedtime
Some possible causes of sleeping with an open mouth can include oral restrictions (tongue or lip tie), high palate, enlarged adenoids, and food intolerances.
Mouth breathing is a deviation from our normal physiology. If your child can't sleep with their mouth closed, we want to know why. Not only so we can fix the mouth breathing, but also so we can prevent the potential health challenges that can follow.
Mouth breathing can cause:
Sleep onset delay
More instances of night wakings
Less slow-wave (deep) sleep
Night terrors
It can also be a risk factor for:
Sleep apnea
Enlarged tonsils or adenoids*
Allergies*
Recurring ear or throat infections and migraines
Improper development of the face and malocclusion and cavities
*Note that this can also be the cause of the mouth breathing!
There is even a suspected link between symptoms that present as attention-deficit/hyperactivity disorder (ADHD) and children who mouth breathe (Kalaskar et al., 2021).
So what do we do?
If your child is mouth breathing, you can ask your pediatrician for referrals to a few different resources:
Pediatric ear, nose, and throat doctor (ENT). They can check for a high palate, whether the tonsils or adenoids are enlarged, and some ENTs will even run allergy tests to see if that’s the culprit.
Airway dentist
Myofunctional therapist
Speech therapist (if they have continuing education in oral restrictions)
While trying to find a provider, I’d personally recommend finding out if they specialise in – or at least have continuing education in – mouth breathing and oral restrictions before meeting with them (since oral restrictions are such a common cause of mouth breathing).
I’ve spoken to many people in these fields who still think oral restrictions can be assessed simply by looking at the tongue, when what is really needed is a functional assessment. It can feel like a huge waste of time to meet with someone about your child’s mouth breathing, only to be met with, "They’ll grow out of it." (No, they won’t).
You might have to meet with multiple different providers to get an answer, which I know can be really frustrating and time-consuming. As someone who has dealt with mouth breathing both with myself and with my infant daughter, I know firsthand how expensive and taxing it can be to jump around from provider to provider until someone takes your concerns seriously. Nevertheless, I want to encourage you to keep advocating for your child until you get answers and support.
Once the cause of the mouth breathing is found, it’s rarely a “quick fix” to nasal breathing, and in many cases, ongoing therapy, exercises, bodywork, or massage will be needed. However, putting in the work now will help ensure your child grows up with healthy breathing (and therefore, sleeping!) habits, which are much harder to change later on in life.
References:
Kalaskar, R., Bhaje, P., Kalaskar, A., & Faye, A. (2021). Sleep Difficulties and Symptoms of Attention-deficit Hyperactivity Disorder in Children with Mouth Breathing. International journal of clinical pediatric dentistry, 14(5), 604–609. https://doi.org/10.5005/jp-journals-10005-1987
Monti, J. M. & Jantos, H. (2004). Microinjection of the nitric oxide synthase inhibitor l-NAME into the lateral basal forebrain alters the sleep/wake cycle of the rat. Progress in neuro-psychopharmacology and biological psychiatry, 28(2), 239–247. https://doi.org/10.1016/j.pnpbp.2003.10.001
What makes my approach different:
The whole gist behind most sleep training programs is that you have to follow their rules for it to work… even if it feels awful.
That’s not what we do here. I will never ask you to do anything that goes against your intuition.
You’re the expert, and you get to call the shots.
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