Get­ting high on their own sup­ply

Cosmos - - Digest -

What makes the Sherpa peo­ple, who have lived in the Hi­malayas for thou­sands of years, so well-adapted to the high-al­ti­tude life, able to func­tion on oxy­gen lev­els that in­ca­pac­i­tate or even kill oth­ers, has in­spired plenty of in­ves­ti­ga­tion.

Past stud­ies point to them hav­ing fewer red blood cells buthigher lev­els of nitric ox­ide, which open up ar­ter­ies and keep blood flow­ing. It turns out, though, that ge­netic adap­ta­tion to a low-oxy­gen en­vi­ron­ment af­fects their whole me­tab­o­lism.

The find­ing comes from re­search by sci­en­tists from the Univer­sity of Cam­bridge mon­i­tor­ing Sher­pas and “low­lan­ders” as they climbed to Ever­est Base Camp, 5,300 me­tres above sea level.

For most peo­ple hy­po­baric hy­poxia (in­suf­fi­cient sup­ply of oxy­gen due to low air pres­sure) sets in at about 3,000 me­tres. The peak of Ever­est is 8,848 me­tres, and any­where above 8,000 me­tres is known as “the death zone”.

Us­ing molec­u­lar, bio­chem­i­cal, phys­i­o­log­i­cal and ge­netic ap­proaches to study the two groups, the re­searchers found that Sher­pas demon­strated a lower ca­pac­ity for fatty acid ox­i­da­tion in skele­tal mus­cles, along with more ef­fi­cient use of oxy­gen, im­proved mus­cle en­er­get­ics, and pro­tec­tion against ox­ida­tive stress.

These meta­bolic adap­ta­tions, the re­searchers write in the jour­nal Pro­ceed­ings of the Na­tional Academy of Sci­ence, ap­pear to be re­lated to an en­riched gene known as the per­ox­i­some pro­lif­er­a­tor-ac­ti­vated re­cep­tor A (PPARA).

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