It really depends on (too) many factors. Out where I work and play, the problem is getting too much sun. An outdoor walk between my office and the lab at the other end of the building gets me plenty sun. Ditto the bike ride home (assuming I'm not working late on something). It also doesn't hurt that I get out to go hiking and climbing on a semi-regular basis. OTOH, if I worked for a startup in Seattle, yeah, I might need to up my intake of vitamin D (which I'm already taking in a multivitamin).

Of course, IANAMD, so the first thing I'd recommend is going to an actual MD if you have health issues - and mention your lifestyle.