Hey, I'm 20 and I find your informations very valuable. Have you a book of reference or anything (for info concerning food like you explain)? Or is it just hard research on the internet?Rowing is a great all-round activity. I also have a water-rower, but I tend to use it more in the winter. I tend to do 2x2000m, I think 7min is my average. Hard to walk after that though - legs like jelly!
Humans evolved outside, without clothes, and yet skin cancer appears to be a relatively moderate issue. Current theory is that it's due to the change in fat consumption towards the omega-6 PUFA's pushed by the food industry since the 1940's (sunflower, canola, etc.). Human cell membranes are O3 based, but if your O3:O6 ratio goes out-of-whack (it should be between 1:1 and 1:2, but in the USA it's typically 1:45) then the body uses O6 instead for the cell membranes, which are inherently unstable and become inflamed easily in sunlight.
Anecdotally, since removing O6 fats from my diet, I can spend all day in the sun, I don't burn. Same for my wife. Note I'm a Brit, so traditionally burn in the sun quickly. My wife is a pure-blond Dane, with skin so white that it's almost translucent, she can also spend all day outside - in when we first met this was not possible, 10 minutes and she was cooked. Many others on a paleo/keto/carnivore WOE have reported the same.
OK, I'll stop with this stuff now we're into pre-market, but I feel this point was particularly important.
Thanks, and sorry for off topic.