I certainly did not know this, Dexter! I know many vegetarians and SAD eaters who are long distance runners/swimmers/cyclists and they are so healthy looking. It never even crossed my mind that these guys are 'over-doing' it, or that they are more susceptible to heart attacks - they are like, the epitome of 'fit'. They garner great respect amongst my friends and I often think about them working so hard to maintain their slim physiques. It came as quite a surprise to me when I first switched to paleo and my body started to look like theirs, but I ran not a mile.
I think that the indoctrination we are exposed to nowadays about saturated fat being bad, aerobic exercise being good is pretty much ingrained into almost all of our brains. Where have these ideas come from and how come they are so persuasive? As Mark Sisson says in the article you cite: "But itʼs not a matter of being stupid. Unlike other animals, we have advertisements and testimonials and hype to deal with, and our tendency is to believe, not to doubt, so we are more susceptible." There certainly is pressure to get out there and do it, absolutely - thankfully, I enjoy walking more than long-distance running and have always preferred 'all-round' exercise like gardening, housekeeping and looking after small children, which involves nearly all of the motions Tim describes (esp. the naps).
Since reading your quote on Tim's question yesterday, about the Greek runner Pheidippides, I have been feeling less guilty that I am not out running every evening like I see so many of my friends doing. I still think I must be labelled as 'lazy' by my friends though - perhaps all this has something to do with some kind of work ethic we are supposed to be subscribing to?
A question I would like to ask is: some races must be more predisposed to long distance running than others, like Ethiopians such as Haile Gebre Selassie for example, do you think this is the case?