Daywalker!
I can guarantee that most of you reading this post aren't getting enough sunlight. I know @heiditravels is, I could use more for sure but most of the current jobs are digital/online based. However, I have come to a major realization we all could use MORE sunlight.
To begin, Vitamin D isn't a vitamin in the true sense. Many scientists actually classify it as a hormone. Vitamin D receptors fill our entire bodies. Why would nature include a sensor for substance throughout the body if it didn't have signaling importance.
Vitamin D - There's a reason all medical practitioners now include this blood test in their panels. Vitamin D might be the single best measurement of overall health we have. In fact, in many PubMed articles, the levels of Vitamin D are associated with the body properly regulated the conversion of sunlight into body energy.
http://www.ncbi.nlm.nih.gov/pubmed/22461123
But wait let's talk about most underdiscussed subjects:
MENTAL HEALTH
The effects of sunlight and Vitamin D on mood and perception of the world are well documented. Sometimes we are placed in conditions were the sunlight or angle the sun hits the Earth doesn't lend itself to optimal production of Vitamin D. This presents a challenge to get greater exposure. Supplementation is critical in these situations. Furthermore, I apologize in advance for those individuals that actually cannot convert sunlight into Vitamin D due to a genetic CYP27B1 mutation.
https://ghr.nlm.nih.gov/gene/CYP27B1
Doesn't take much but try to get 20-30 minutes of sunlight today.
Good Luck.