We have all heard of the benefits of vitamin D recently. The importance can't be underestimated. However, this is about the rest of the good stuff that a little sunshine is doing through your body.
The eyes have photosensitive cells in the retina that have influence on the pituitary gland. These cells also influence the hypothalamus gland that helps control our circadian rhythm, which in turn, influences sleep patterns. Sleep, good or bad, will influence our hormones.
Lastly, the pineal gland is influenced. This is where melatonin is produced. It happens in the dark while you sleep. (even a small amount of light on the skin can disrupt this process) This is where you get the nice tan! Most importantly this influences sleep, is an antioxidant and also helps with depression. I recently just found out that aspirin decreases melatonin. ( big time info)
Take away this, when you wake up in the morning get some sunshine on those eyeballs. It will help with a lot of important bodily functions, not just Vit D.
I got a lot of this information from Phil Maffetone.
-train out pain and train in performance!