If they really have controlled for that factor, shouldn't we see similar results from people with sedentary lives, but high UV exposure? (possibly by regular use of tanning beds or the like?) Being prescribed UV exposure is an interesting idea for the future.
[0] https://www.medrxiv.org/content/10.1101/2023.07.11.23292360v...
I was held in cells without windows for five years. The other five the cells had windows but were so dirty that practically no sunlight entered. Never went outside. Maybe a total of 10 hours outside in 10 years. The first five years in a facility where they didn't design any outside into it because it was built in the middle of a downtown area and there wasn't space. The other five in a facility that had large outside areas but no staff to organize corralling a whole cellblock of inmates, getting them through the corridors of the buildings to the outside, monitoring them so they didn't escape and then getting them back. That requires a lot of staff, and most jails and prisons are vastly understaffed.
Here's what I wrote about the sunlight:
As a general just-so-story rule of thumb to be discounted in the face of evidence to the contrary, stimulus or stress that's a consequence of doing stuff generally acts as a "growth factor" even if it causes slight damage, including exercise, heat and cold shock, and sunlight.
Broad-spectrum vs tanning.
And outside also gets lower CO2 and VOC.