Do a bit of reading on the mitochondria, ATP and the electron transport chain. I still don't understand exactly the mechanism, but it seems that our cells might share some characteristics with photosynthetic cells, and certain kinds of light might increase energy production on a cellular level. From what I remember in bio class, light energy sets off chain reactions by displacing electrons in photosynthetic cells. This paper was from 2008, and they specifically call out low-intensity red light and near-infrared light. Seems like this idea has been floating around for a while now, and somewhat well backed up.
If only more people would take the time to read the existing literature and studies before they say things like "this is dubious" without having a shred of understanding what it is they are talking about.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2996814/ https://photosynthesiseducation.com/photosynthesis-in-plants...