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Does wearing a mask for long periods of time affect the brain causing lethargy, headache, and dizziness because of lack of oxygen?

Update

The claim that the prolonged use of face masks can cause oxygen deficiency, carbon dioxide intoxication, dizziness, or other health challenges is not grounded in science. Science shows that the risks associated with wearing masks are generally minimal, and the benefits plenty. Even if a person is wearing an airtight medical grade mask, like an N95 or FFP2 mask, the risks of lethargy, headache, and dizziness are low, even after wearing one for several hours. For an average healthy person wearing a cloth or surgical mask, there is even less risk of these symptoms occurring, because they still allow oxygen to flow out of the mouth and nose freely. While it might feel like breathing is more difficult in a mask and you are not getting enough air, that is likely a response to stress or anxiety from wearing the mask and can usually be helped by focusing on normal breathing patterns. Shallow breathing, hyperventilation, and breath holding can cause increases in carbon dioxide which leads to headaches and nausea. These symptoms are generally not caused by the use of masks.

This article was published on
February 17, 2021

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What our experts say

The claim that the prolonged use of face masks can cause oxygen deficiency, carbon dioxide intoxication, dizziness, or other health challenges is not grounded in science. Science shows that the risks associated with wearing masks are generally minimal, and the benefits plenty.

Even if a person is wearing an airtight medical grade mask, like an N95 or FFP2 mask, the risks of lethargy, headache, and dizziness are low, even after wearing one for several hours. For an average healthy person wearing a cloth or surgical mask, there is even less risk of these symptoms occurring, because they still allow oxygen to flow out of the mouth and nose freely.

While it might feel like breathing is more difficult in a mask and you are not getting enough air, that is likely a response to stress or anxiety from wearing the mask and can usually be helped by focusing on normal breathing patterns. Shallow breathing, hyperventilation, and breath holding can cause increases in carbon dioxide which leads to headaches and nausea. These symptoms are generally not caused by the use of masks.

Context and background

The claim that the prolonged use of face masks can cause oxygen deficiency, dizziness, or other health challenges is not grounded in science. In fact, healthcare workers often wear masks for long hours in the hospital. There is no evidence that surgical masks or cloth masks cause significant deficiency of oxygen. This information has been primarily circulating on social media among individuals or communities resistant to mask-wearing in general. While masks are restrictive and can feel like they impede air flow, properly designed masks do allow air flow by design, and the feeling of inconvenience or minor discomfort does not equate to health risks such as a lack of oxygen. Low oxygen levels in the blood (hypoxemia) can cause issues in the body to not receive enough oxygen (hypoxia), but both are unlikely to happen as a result of wearing a properly designed mask or face covering.

Wearing a mask (preferably a cloth mask over a surgical mask) is recommended to protect people from community transmission of COVID-19. There are only a few exceptions to this public health recommendation, mostly focused on children under 2 years of age and people with serious medical conditions that can make it difficult to breathe through a mask or remove a mask if necessary. Otherwise, wearing a mask is safe and helpful for preventing the spread of COVID-19.

Resources

  1. From the Frontlines: The Truth About Masks and COVID-19 (American Lung Association)
  2. Maximizing Fit for Cloth and Medical Procedure Masks to Improve Performance and Reduce SARS-CoV-2 Transmission and Exposure, 2021 (U.S. CDC)

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