It's been a while since I posted, but I saw something interesting on BBC news.
Several people (including me) have reported that sunshine seems to help prevent/treat POIS. We thought that perhaps this was because the UV rays help the body to produce Vitamin D. However, BBC news says that a new research paper from Edinburgh University shows that UV rays cause the body to release nitric oxide:
http://www.bbc.co.uk/news/uk-scotland-edinburgh-east-fife-22433359The article focuses on how nitric oxide reduces blood pressure - no doubt this is true. But nitric oxide also plays a key role in humans getting an erection.
Quoting the wikipedia entry for nitric oxide:
"Sildenafil citrate, popularly known by the trade name Viagra, stimulates erections primarily by enhancing signaling through the nitric oxide pathway in the penis"
I am fortunate enough that I am now living in a sunny climate, and my POIS symptoms are considerably reduced from when I was living in a cold country. Could a lack of Nitric Oxide be one of the reasons that we get POIS?