…[T]here is one man whose physiological performance defies all convention: Dean Karnazes is an ultrarunner from California and, at times, it seems as if he can run forever.
Karnazes has completed some of the toughest endurance events on the planet, from a marathon to the South Pole in temperatures of -25C to the legendary Marathon des Sables, but in his entire life he has never experienced any form of muscle burn or cramp, even during runs exceeding 100 miles. It means his only limits are in the mind.
Karnazes says he once ran for three days and nights continuously, and he only stopped because he got sleepy.
Karnazes doesn’t seem to have what’s called a lactate threshold:
While supreme willpower is a common trait among ultrarunners, Karnazes first realised that he was actually biologically different when preparing to run 50 marathons in 50 days across the US back in 2006. “I was sent to a testing center in Colorado,” he recalls. “First, they performed an aerobic capacity test in which they found my results consistent with those of other highly trained athletes, but nothing extraordinary. Next, they performed a lactate threshold test. They said the test would take 15 minutes, tops. Finally, after an hour, they stopped the test. They said they’d never seen anything like this before.”
And in unrelated news, we’re getting fatter all the time.
Oh, you already knew that? Well, I’m not talking about just Americans. Or about people in general. Or even about just their pets and zoo animals. This refers to animals under many other conditions, too, such as lab rats, who are taking in the same amount of food as before and yet getting heavier.
I feel their pain.
Rats, mice and primates (four types were analyzed in this study) in laboratories are fed a highly controlled, known diet that has remained relatively constant over time. Why are these animals getting fatter?
Perhaps for some reason they’re choosing to eat more of what they are offered or are somehow changing how they metabolize it, he said.
Allison pointed out at least three potential contributions to this and the other observations: endocrine disrupting chemicals, pathogens such as a virus, and/or changes in temperature where the animals are kept.
I read several articles on the subject, and nowhere did I see speculation on whether animals’ gut flora might have changed in a way that favors weight gain. So I’m here to offer that idea. It’s not so very fanciful, either; a phenomenon of the sort seems to be true of humans.