*Please never, ever listen to our advice.
People Who Live at High Altitudes Have More Strength With Less Oxygen
Out of 7.2 billion people alive today, roughly 140 million live at an altitude 2,500 meters (8,200 feet) or higher. And those people might as well be a whole other goddamn species.
For most humans, prolonged exposure to high altitude leads to a number of unpleasant symptoms, such as nausea, heart disease, delirium, and good old-fashioned death. Survive up there long enough, though, and you begin to evolve past those issues and become stronger. Take Tibet, for example. Over 2,750 years ago, the Tibetan people split from mainland China and decided to live in the mountains instead. At over two and a half miles up, the world is very different indeed. The air is thinner and contains 40 percent less oxygen than the air we lower-landlubbers breathe. Of course, that doesn't mean Tibet is a deadly, unlivable void-space. It's only 40 percent of a deadly, unlivable void-space.
Antoine Taveneaux, via WikipediaDon't let the mystic beauty fool you; this place is a dick-kick to the cardiorespiratory system.
After millennia, Tibetans' bodies adapted to these conditions, bestowing upon them some of the highest endurance levels on the planet. They've done so by pure mutation: The EPAS1 gene normally produces more red blood cells once the body is deprived of oxygen. In Tibetans, the gene actually creates fewer cells in lower-oxygen environments. Now, no scientists have ever said that the following statement is actually true (and for some stupid reason, they call the cops whenever you try to test it), but we're pretty sure that means Tibetans will only get stronger when you suffocate them.
Then there are the Kalenjin people of Kenya: Their forefathers belonged to the Nilotic tribes, and they lived at sea level for thousands and thousands of years. Only recently have the Kalenjin moved to their current home of the Great Rift Valley, at roughly 7,000 feet above sea level. This means that, unlike the Tibetans, whose genetic superpower prevents them from overdeveloping red blood cells, a Kalenjin's body may function like it's constantly adapting to the higher altitude, thus producing a gargantuan amount of red blood cells. When they descend to mere mortal ground, the extra oxygen could very well manifest itself in their most famous attribute: running forever and ever.
Tom Page, via Wikipedia
"Take my picture quick; I'll need to start early if I'm gonna jog back to Kenya by tomorrow."