A peer-reviewed journal that offers evidence-based clinical information and continuing education for dentists.

Functional Breathing in the Era of the N95

Terri Patrick, RDH, MS, CHES—an orofacial myofunctional therapist—is blogging for Decisions in Dentistry about COVID-19.

Returning to clinical practice has left many oral health professionals wondering if they can get used to wearing N95 respirators or equivalents all day, every day. With reduced flow of oxygen due to breathing through these high-level masks and increased warmth from wearing additional personal protective equipment (PPE), many oral health professionals are struggling. The practice of functional breathing can help.

The United States Centers for Disease Control and Prevention recommends that oral health professionals use an N95 mask or other approved respirator that offers a high level of protection during aerosol-generating procedures.1 If this level of mask is unavailable, a surgical level III mask with face shield is the minimum recommended. However, fitted respirators are more effective against inhalation of airborne infectious agents, in part due to the snug fit against the face.

These are unprecedented times, and a variety of personal air filtration devices/barriers in addition to ambient air sanitizing methods are in use, even as recommendations continue to change. For example, Stanford engineers are developing a way to run oxygen through N95 masks.2 This addition could be helpful, as available oxygen inside N95 masks can be reduced up to 20%.2

In the meantime, oral health professionals are struggling to breathe. With a lack of oxygen due to respirator use, balancing loupes with a headlight, seeing through face shields, and the warmth created by donning more PPE, clinicians are working up a sweat. Breathing gets more difficult with a lack of oxygen, resulting in higher pulse and blood pressure rates. Mouths open to bring in more air, drying oral tissues and airways. The many benefits of nasal breathing are secondary to the need for air.

Inhaling more carbon dioxide (CO2) is another consideration. CO2  is necessary but breathing problems arise when proper oxygen/CO2 ratio is disturbed. Hypercapnia occurs when exhaled CO2 is continually inhaled from the dead space in the respirator, activating the sympathetic nervous system. Excessive CO2 exacerbates this fight or flight response, causing the body to hyperventilate. CO2 is a vasodilator, raising blood pressure and body temperature.3 Additionally, lack of adequate oxygen encourages open-mouth breathing in attempt to bring in more air.4

Individual tolerance to CO2 exposure and its symptoms vary according to fitness level, comorbidity, and breathing pattern. The good news is tolerance can be increased. Those who have been medically cleared for the respirator fit test can take measures to decrease their CO2 sensitivity. To learn your level of sensitivity to CO2, measure your control pause or body oxygen level test (BOLT) score with these instructions.5,6

Measure Your Sensitivity to CO2

  1. Rest for 5 minutes.
  2. Sit straight without crossing your legs and breathe comfortably and steady.
  3. After an exhalation pinch your nose.
  4. Hold your breath and start stopwatch.
  5. When you feel slight discomfort, resume your breathing and note the time.

This exercise measures the time it takes for your body to react to a lack of air. After the breath hold, the next inhalation should be calm. A healthy score is 25 to 40. A lower score indicates sensitivity to CO2 and a greater breathing demand. At lower levels, the lungs have to work harder to remove excessive CO2. Those with higher scores can maintain calmer, more relaxed breathing during rest and exertion.

Various breathing methods and exercises are available to reduce CO2 sensitivity. Any that activate the parasympathetic (rest and digest) nervous system and support light, slow, and deep breathing can improve the control pause score. The Buteyko technique uses exercises to improve CO2 sensitivity scores.7

Oral health professionals may want to implement functional breathing exercises on their days off when they are relaxed. Be sure to breathe through your nose, both in and out. Are you congested? Lower controlled pause scores correlate with congestion. As your breathing improves, so will your congestion. Try this exercise to immediately unblock the nose.8

Nose Unblocking Exercise

  1. Take a small breath in through your nose and breathe out through your nose.
  2. Pinch your nose and walk around or, if sitting, sway back and forth while holding your breath.
  3. When the desire to take a breath is fairly strong, let go of your nose.
  4. Breathe in only through your nose.
  5. Repeat the cycle while breathing in and out only through your nose until your nose is unblocked.

Observe your breathing throughout the day. Good breathing during rest should not be seen or heard. A typical respiratory rate is around 10 to 20 breaths per minute.9 A higher BOLT score correlates with fewer breaths/minute, which improves overall oxygen exchange. More efficient oxygenation of tissues improves energy and concentration. Additionally, a slower breathing pattern activates the parasympathetic nervous system, which, in turn, lowers pulse rate, helping to reduce anxiety and stress.

We can go weeks without eating and days without drinking, but only minutes without breathing; yet, we pay less attention to our breathing than what we eat and drink. The importance of healthy air and breathing cannot go unnoticed. We are learning as best practices evolve. Stay safe and listen to your body.


  1. US Centers for Disease Control and Prevention. Guidance for Dental Settings. Interim Infection Prevention and Control Guidance for Dental Settings During the COVID-19 Response. Available at: https://www.cdc.gov/coronavirus/2019-ncov/hcp/dental-settings.html#PPE. Accessed June 21, 2020.
  2. Meyers A. COVID-19 prompts Stanford engineers to rethink the humble face mask. Available at: https://news.stanford.edu/2020/04/14/stanford-researchers-reengineer-covid-19-face-masks/. Accessed June 21, 2020.
  3. Battisti-Charbonney A, Fisher J, Duffin J. The cerebrovascular response to carbon dioxide in humans. J Physiol. 2011;589:3039–3048.
  4. National Library of Medicine. PubChem: Carbon-Dioxide. Available at: https://pubchem.ncbi.nlm.nih.gov/compound/Carbon-dioxide. Accessed June 21, 2020.
  5. Buteyko A … Z. Practical Elements. Available at: http://www.buteyko.com/practical/elements/index_elements.html. Accessed June 21, 2020.
  6. McKeown P. The Oxygen Advantage: Simple, Scientifically Proven Breathing Techniques. New York: Harper Collins: 2015:32–50.
  7. Buteyko Clinic International. The Life of Konstantin Buteyko. Available at: https://buteykoclinic.com/about-dr-buteyko/. Accessed June 21, 2020.
  8. Buteyko Clinic International. Nose Unblocking Exercise. Available at: https://buteykoclinic.com/nose-unblocking-exercises/. Accessed June 21, 2020.
  9. Russo MA, Santarelli DM, O’Rourke D. The physiological effects of slow breathing in the healthy human. Breathe. 2017;13:298–309.
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