Researchers at the ICFO Institute in Barcelona have used biophotonic technologies to test whether wearing a facemask alters the body’s oxygen levels. The results show small changes in brain haemodynamics, but comparable to everyday activities such as hearing a sound, seeing someone moving or bending down to tie our shoes.
The masks seem to be here to stay, although there is still debate about their possible effects on the body.
To try to shed some light on this question, researchers Jonas Fischer and Lisa Kobayashi Frisk from the Institute of Photonic Sciences (ICFO), led by ICREA Professor Turgut Durduran, have collaborated with the University Hospital of Zurich (Switzerland) and the Hospital de la Santa Creu i Sant Pau in Barcelona.
To see if the use of face masks can affect the amount of oxygen reaching the brain, the haemodynamics and oxygenation of the cerebral microvasculature were assessed using biophotonic technologies.
To see if the use of facemasks can affect the amount of oxygen reaching the brain, the team assessed the haemodynamics (part of biophysics that studies the dynamics of blood) and oxygenation of the brain’s microvasculature, using biophotonic technologies. The results are now presented in the journal PNAS.
The researchers recruited a group of healthy young adults as participants, who sat in a chair reading a scientific article, first without a mask and then with it on. Both surgical masks and FFP2 were tested.
Two forehead probes
By placing two probes on the participants’ foreheads while they read, the researchers measured blood flow, oxygenation and oxygen metabolism in the brain. These probes use two non-invasive, infrared biophotonic technologies known as diffuse correlation spectroscopy and time-resolved near-infrared spectroscopy (DCS and TR-NIRS).
They also measured general body function, assessing heart rate, respiration, and the amount of oxygen and carbon dioxide.
After monitoring the brain, the researchers processed the data and performed statistical analyses to see if there were any changes in the signals received, both with and without masks.
Small changes in the amounts of oxygen in the brain and cerebral blood flow were observed with the use of facemasks, but comparable to those that occur during everyday activities.
The team did not observe any significant changes in body levels of oxygen and carbon dioxide. However, they did observe small, statistically significant variations in the amounts of oxygen in the brain and cerebral blood flow with the use of both types of facemasks.
The researchers conclude that these observed changes are comparable to those that occur daily when we perform other everyday activities, such as hearing a sound, seeing someone moving around or bending down to tie our shoes.
In addition, they stress that their protocol could be useful to further investigate the effects of wearing facemasks in other types of populations such as the elderly, children, patients with previous respiratory pathologies or when performing critical work.
They also point out that facemasks could interfere with monitoring or neuroimaging studies, and that in such cases their use should be avoided or study subjects should be closely supervised.
Jonas B. Fischer et al. “Cerebral and systemic physiological effects of wearing face masks in young adults”. PNAS, 2021.