Altitude sickness peaks in Ladakh

But just why this Himalayan region makes people so ill is baffling scientists

For trekkers and mountaineers, scientists have issued a mysterious warning. The worst place in the world for altitude sickness is Ladakh, the stark, beautiful region on India's northern border with China and Tibet – and nobody knows exactly why.

Ladakh, literally "the land of high passes", lies between the Himalayas and the Kunlun mountain range at a height of more than 3,000 metres (9,800 feet). It is a high-altitude desert which has become a popular destination for adventure travellers in the last decade, drawn by its remote culture and extraordinary panoramas.

Now the largest study of visitors to mountainous regions around the world who were previously assessed for their vulnerability to altitude sickness has found that Ladakh presented the biggest threat.

Jean-Paul Richalet, professor of physiology at the University of Paris North, who led the study published in the American Journal of Respiratory and Critical Care Medicine, said: "When adjusted for all other risk factors, especially rate of ascent, one location – Ladakh – remained associated with a higher risk of severe high-altitude illness."

But the researchers were unable to identify why the region had the greatest impact. "No clear explanation, linked to the climate or the difficulty of the terrain is available, although many informal reports mention the higher risk of this location," Dr Richalat said. The researchers assessed more than 1,300 people who planned excursions to mountainous areas which involved at least three days above 4,000 metres, and sleeping overnight above 3,500 metres.

Before they left, they were given a series of tests to measure their breathing and heart rate at low-oxygen levels – to mimic the effects of high altitude – and the results were compared with their actual experience after they returned from their trip.

Almost one in four (318) suffered a severe altitude illness with symptoms of headache, nausea, fatigue and dizziness, associated in the some cases with swelling of tissue in the lungs and brain.

The study is the first to suggest an association between the geographical location of ascent and altitude sickness. The drug acetazolamide (Diamox) cut the risk of developing the condition among the participants by 44 per cent, the study found. Neverthleless, among the 318 who developed altitude sickness, a third (105) had used Diamox.

The research revealed potential risk factors for altitude sickness. Participants who experienced a significant reduction in the amount of oxygen in the blood when exercising in a low-oxygen environment were more likely to develop symptoms.

A common experience at altitude is how breathing fails to keep pace with the demands of the body which triggers involuntary gasps for air and a feeling of suffocation. A conscious effort to breathe faster and deeper is necessary as part of acclimatisation.

But getting fit is no defence against altitude sickness. The study found that those who took most exercise to prepare for their trip were at increased risk from the condition. "Those who visit high altitudes should realise intense aerobic training is not a predictor of success in high-altitude expeditions," Dr Richalet said.

Start your day with The Independent, sign up for daily news emails
Have you tried new the Independent Digital Edition apps?
ebooks
ebooksA special investigation by Andy McSmith
News
Nick Clegg on the campaign trail in Glasgow on Wednesday; he says education is his top priority
peopleNick Clegg remains optimistic despite dismal Lib Dem poll ratings
Arts and Entertainment
Buttoned up: Ryan Reynolds with Helen Mirren in ‘Woman in Gold’
filmFor every box-office smash in his Hollywood career, there's always been a misconceived let-down. Now he says it's time for a reboot
News
people
News
Actress Julianne Moore wins the Best Actress in a Leading Role Award for 'Still Alice' during the 87th Annual Academy Awards in Hollywood, California
people
Sport
Ross Barkley
footballPaul Scholes says it's time for the Everton playmaker to step up and seize the England No 10 shirt
News
'We will fix it': mice in the 1970s children’s programme Bagpuss
science
Life and Style
2 Karl Lagerfeld and Choupette
fashion
  • Get to the point
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Recruitment Genius: Customer Service Executive

£18000 - £22000 per annum: Recruitment Genius: This is an exciting opportunity...

Recruitment Genius: Retail Buyer / Ecommerce Buyer

£30000 - £35000 per annum: Recruitment Genius: Working closely with the market...

Recruitment Genius: Sales Executive - CAD Software Solutions Sales

£20000 - £50000 per annum: Recruitment Genius: A reputable company, famed for ...

Ashdown Group: Client Accountant Team Manager - Reading

Negotiable: Ashdown Group: The Ashdown Group has been engaged by a highly resp...

Day In a Page

War with Isis: Iraq declares victory in the battle for Tikrit - but militants make make ominous advances in neighbouring Syria's capital

War with Isis

Iraq declares victory in the battle for Tikrit - but militants make make ominous advances in neighbouring Syria
Scientists develop mechanical spring-loaded leg brace to improve walking

A spring in your step?

Scientists develop mechanical leg brace to help take a load off
Peter Ackroyd on Alfred Hitchcock: How London shaped the director's art and obsessions

Peter Ackroyd on Alfred Hitchcock

Ackroyd has devoted his literary career to chronicling the capital and its characters. He tells John Walsh why he chose the master of suspense as his latest subject
Ryan Reynolds interview: The actor is branching out with Nazi art-theft drama Woman in Gold

Ryan Reynolds branches out in Woman in Gold

For every box-office smash in Ryan Reynolds' Hollywood career, there's always been a misconceived let-down. It's time for a rethink and a reboot, the actor tells James Mottram
Why Robin Williams safeguarded himself against a morbid trend in advertising

Stars safeguard against morbid advertising

As film-makers and advertisers make increasing posthumous use of celebrities' images, some stars are finding new ways of ensuring that they rest in peace
The UK horticulture industry is facing a skills crisis - but Great Dixter aims to change all that

UK horticulture industry facing skills crisis

Great Dixter manor house in East Sussex is encouraging people to work in the industry by offering three scholarships a year to students, as well as generous placements
Hack Circus aims to turn the rule-abiding approach of TED talks on its head

Hack Circus: Technology, art and learning

Hack Circus aims to turn the rule-abiding approach of TED talks on its head. Rhodri Marsden meets mistress of ceremonies Leila Johnston
Sevenoaks is split over much-delayed decision on controversial grammar school annexe

Sevenoaks split over grammar school annexe

If Weald of Kent Grammar School is given the go-ahead for an annexe in leafy Sevenoaks, it will be the first selective state school to open in 50 years
10 best compact cameras

A look through the lens: 10 best compact cameras

If your smartphone won’t quite cut it, it’s time to invest in a new portable gadget
Paul Scholes column: Ross Barkley played well against Italy but he must build on that. His time to step up and seize that England No 10 shirt is now

Paul Scholes column

Ross Barkley played well against Italy but he must build on that. His time to step up and seize that England No 10 shirt is now
Why Michael Carrick is still proving an enigma for England

Why Carrick is still proving an enigma for England

Manchester United's talented midfielder has played international football for almost 14 years yet, frustratingly, has won only 32 caps, says Sam Wallace
Tracey Neville: The netball coach who is just as busy as her brothers, Gary and Phil

Tracey Neville is just as busy as her brothers, Gary and Phil

The former player on how she is finding time to coach both Manchester Thunder in the Superleague and England in this year's World Cup
General Election 2015: The masterminds behind the scenes

The masterminds behind the election

How do you get your party leader to embrace a message and then stick to it? By employing these people
Machine Gun America: The amusement park where teenagers go to shoot a huge range of automatic weapons

Machine Gun America

The amusement park where teenagers go to shoot a huge range of automatic weapons
The ethics of pet food: Why are we are so selective in how we show animals our love?

The ethics of pet food

Why are we are so selective in how we show animals our love?