Physical Characteristics
Tibetans are phenotypically diverse. Recent research into the ability of Tibetans' metabolism to function normally in the oxygen-deficient atmosphere above 4,400 metres (14,400 ft) shows that, although Tibetans living at high altitudes have no more oxygen in their blood than other people, they have 10 times more nitric oxide and double the forearm blood flow of low-altitude dwellers. Nitric oxide causes dilation of blood vessels allowing blood to flow more freely to the extremities and aids the release of oxygen to tissues. It is not known whether the high levels of nitric oxide are due to a genetic mutation or whether people from lower altitudes would gradually adapt similarly after living for prolonged periods at high altitudes.
Read more about this topic: Tibetan People
Famous quotes containing the word physical:
“A separation situation is different for adults than it is for children. When we were very young children, a physical separation was interpreted as a violation of our inalienable rights....As we grew older, the withdrawal of love, whether that meant being misunderstood, mislabeled or slighted, became the separation situation we responded to.”
—Roger Gould (20th century)