Tibetans are special

How Tibetans Enjoy the High Life: Scientific American

Here's an interesting story on how it is that Tibetans manage to live in such thin air:

The Tibetans increase their blood flow by producing prodigious amounts of nitric oxide in the linings of the blood vessels. This gas diffuses into the blood and forms nitrite and nitrate, which cause the arteries and capillaries to expand and deliver oxygen-bearing blood to the rest of the body more rapidly than normal. ... Also, the nitric oxide by-products circulating in Tibetan blood are 10 times greater.

In fact, the Tibetan levels of these nitrites and nitrates are higher than those in patients suffering from a bacterial blood infection—septic shock—and the blood flows are typical of people suffering from high blood pressure. Yet, they have no ill effects in Tibetans. "We don't see an increase in vascular resistance," Beall says. The Tibetans also appear to have higher levels of antioxidants in their bodies, perhaps to help reduce the risk of putting so much nitric oxide—a free radical—into their bloodstreams.

The curious thing is (which, incidentally, I haven't seen mentioned in any of the versions of this story about Tibetans, but just was my own recollection) is that nitric oxide has an important role in penile erections.

Is Viagra not needed in Tibet?