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Tibetans and Viagra - the missing link?

Viagra
A Viagra like drug maybe used to allow climbers to mimic the body chemistry of high altitude people like Tibetans.  


By Nick Easen
CNN Hong Kong Bureau

(CNN) -- Could the blockbusting anti-impotency drug Viagra and high altitude living Tibetans possibly have anything in common?

Scientists on two sides of the Atlantic seem to think so, the link being a chemical known as nitric oxide.

Recent research shows that the same chemical that increases blood flow in Tibetan's lungs allowing them to breathe at high altitudes, also gives lift to a flagging penis.

British doctors and U.S. anthropologists are independently researching how man copes with high altitude and both agree that nitric oxide is a key factor.

The findings may help to explain why some people adapt easily to high altitude, why others suffer from mountain sickness and how best to treat it -- potentially with a Viagra-like drug.

Tibetans and Bolivians, who dwell in some of the world's highest places, have more nitric oxide in their blood than people living at lower altitudes, according to Cynthia Beall, an anthropologist at Case Western University, Cleveland, Ohio.

Mt Everest climbers may one day be able to ascend without the fear of altitude sickness and its sometimes fatal consequences.
Mt Everest climbers may one day be able to ascend without the fear of altitude sickness and its sometimes fatal consequences.  

When Professor Martin Wilkins of Hammersmith Hospital, London tested Viagra on Kyrgyz people -- who suffer from altitude diseases having only lived on the high Tien Shan mountain range for 500 years -- he found that the impotency drug also allowed them to breathe more easily.

It is not yet known how Tibetans and Bolivians produce higher levels of nitric oxide in their blood.

However, Professor Wilkins told CNN that the body chemistry involved in both high altitude dwellers and those that have taken Viagra, "is quite possibly the same."

How Viagra works

Scientists have found that the same enzyme that constricts blood flow to the penis, preventing erections, also produces breathlessness at high altitudes by constricting the arteries in the lungs.

When Viagra is taken it inhibits the action of this enzyme, known as phosphodiesterase.

In the lungs this is crucial, as nitric oxide has the ability to dilate blood vessels and reduce blood pressure allowing people to avoid high altitude sickness.

In the past nitric oxide has been used to relieve the symptoms of altitude, also known as high altitude pulmonary edema (HAPE).

HAPE causes fluid retention in the lungs, difficulty in walking and sleeping, as well as listlessness and is one of the most dangerous forms of mountain sickness.

Tibetans and Bolivians

Only genetically adapted Tibetans and Bolivians can survive at high altitudes
Only genetically adapted Tibetans and Bolivians can survive at high altitudes  

Cynthia Beall and her colleagues found that Tibetans and Bolivians had as much as twice the amount of nitric oxide in their lungs than those at low altitudes.

The scientists suspect that the high concentration of nitric oxide in their lungs enables increased blood flow allowing them to take up more oxygen where it is in short supply.

Beall and her colleagues measured concentrations of nitric oxide exhaled by Tibetans and Bolivians living at 4,200 metres (13,800 ft) and 3,900 metres (12,800 ft).

These two distinct populations from different opposite sides of the globe appear to have similar adaptations to high altitudes.

They are planning further studies to determine what exactly allows the two populations to produce high levels of nitric oxide.

When asked whether he thought the findings were significant Professor Wilkins said "Yes I do, we are also interested in the genetics of these people and how they are adapted to high altitudes".

Different ethnic groups have spent varying amounts of time at altitude and are likely to show varying genetic adaptation to altitude.

The Kyrgyz people still suffer some forms of altitude sickness, whereas Tibetans have been living on the high plateau for up to 25,000 years and are likely to have greater genetic adaptation.

Mountaineering wonder drug?

After addressing the significance of nitric oxide by both research parties, Professor Wilkins believes that a lot more needs to be done before a Viagra like drug could be administered to mountain climbers, in order to avoid acute mountains sickness or HAPE.

However, after the current hype surrounding these findings Wilkins says, "I think people will try Viagra, however its quite short acting around 2-4 hours for the sexual act, mountaineers would need coverage for up to 24 hours."

If climbers are afraid of having embarrassing erections at altitude, Wilkins gave reassurances saying "we are hopeful to get away with lower doses, Viagra is currently administered in large doses."

He stressed that there is currently no data on the full beneficial effects of Viagra to climbers and that more research is needed.



 
 
 
 



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