NHS doctor proves masks do NOT affect breathing

Dr Joshua Wolrich, 30, form London, has taken to Twitter to demonstrate how face masks do not affect a person's breathing - by measuring his oxygen saturation levels before and after wearing one. https://www.dailymail.co.uk/femail/article-8529353/NHS-doctor-proves-masks-NOT-affect-breathing.html?ns_mchannel=rss&ns_campaign=1490&ito=1490