Question & Answer

Do face masks reduce the amount of oxygen you breathe, causing you to feel faint?

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  • Evidence suggests that wearing a face mask reduces the amount of droplets scattered from the nose and mouth. There is general agreement from the WHO, US CDC and other organisations that individuals who develop suspected COVID-19 with respiratory symptoms (coughing and/or sneezing) should wear face coverings in combination with other measures (e.g. self-isolation, hand hygiene, respiratory etiquette etc) to help prevent the spread of COVID-19.
  • While it may feel uncomfortable to wear face masks for a long time, there is no evidence to suggest that wearing face masks causes a reduction in the amount of oxygen we breathe or that it causes increased levels of carbon dioxide (CO2).
  • TheWorld Health Organization states that the prolonged use of medical masks (flat or pleated masks) when properly worn, does not cause CO2 intoxication or oxygen deficiency. However, the WHO does not advise people to wear masks when exercising, as masks may reduce the ability to breathe comfortably.
  • The type (i.e. material used) and design of face masks can affect the comfort and feeling of breathability.
  • If people who do not have symptoms wear face coverings (non-medical masks) where social distancing is difficult g. on public transport and in shops, it may help prevent spread of COVID-19.
  • Face coverings should NOT be worn by children under the age of 13 or anyone who has trouble breathing, is unconscious, incapacitated, or otherwise unable to remove the mask without assistance.
  • A cloth face covering should cover the nose and go under the chin and fit snugly but comfortably against the side of the face, include at least 2 layers of fabric and allow for breathing without restriction.
  • After they have been used, face masks and coverings, must be washed and/or recycled (reusable masks) or disposed of appropriately (single-use masks) in combination with other measures. handwashing, physical distancing and respiratory etiquette.
  • Face coverings alone are not sufficient to prevent the spread of COVID-19. They are NOT a replacement for other recommended measures e.g. hand hygiene, respiratory etiquette, social distancing etc, and, prior to wearing, must be supported by adequate training on how to safely use face coverings (including how to put them on and take them off safely).
  • Medical Masks intended for healthcare workers are not recommended for use by the public, according to the Health Protection Surveillance Centre. The term ‘face covering’ is often used to refer to non-medical masks.
  • Research in this area is rapidly evolving, and it is expected that recommendations will continue to evolve accordingly.

Things to Remember


  • Lead Researcher: Dr Sonja Khan, HRB Clinical Research Facility, University Hospital Galway and NUI Galway
  • Reviewed by: Elaine Finucane, HRB-Trials Methodology Research Network, School of nursing and Midwifery, NUI Galway.
  • Evidence Advisor: Prof Dearbháile Morris School of Medicine, and Centre for One Health, NUI Galway.
  • Evidence Advisor: Deirdre Mac Loughlin, PPI Ignite, NUI Galway.
  • Journalist Advisor: Dr Claire O’Connell, Contributor, The Irish Times.