Two doctors you would not expect to do a presentation together.

One is a carnivore, the other emphasizes plant based eating. Both very smart with influential Youtube channels. 

https://m.youtube.com/watch?v=VLmn_P3eBuU

Some interesting stuff about covid and infrared light around minute 36:20.

Worth the hour plus listen. Great anecdotal story starting at the one hour mark.

Infrared light penetrates clothes. So even being outside fully clothed has benefits. If you feel the warmth of the sun on the side facing the sun, it is penetrating.