It's surprising this article doesn't significantly mention sunlight's non-UV components, like infrared light. There appears to be increasing evidence to support its ability to influence various processes within the body to positive effect.

MedCram has some easily digestible reviews on the topic:

- The ability for light to influence glucose metabolism: https://www.youtube.com/watch?v=6Win49aeh8A

- Light's effect on immune response and other processes: https://www.youtube.com/watch?v=5YV_iKnzDRg