The key is to find a safe mask (ICU quality) that's comfortable, and you can wear for a long periods of time. I've been using the Respokare N95 Respirator Mask, and find I hardly notice it after hours of wearing it.
Here’s a short video done by a Critical Care Pulmonologist which explains it far much better than I could.
They're not cheap, but they are on-sale now @ 50% off at the attached link.
https://n95maskco.com/
Best of luck