Be it on Mount Kilimanjaro, in the Andes, Himalayas or somewhere else, mountaineering can give you an unforgettable high. But it comes with a risk that's often underestimated though: altitude sickness.
According to the German press agency (dpa), climbing too quickly can cause serious health problems, experts said.
“The risk of getting altitude sickness significantly increases at an elevation of about 2,500 meters,” said Dr. Tomas Jelinek, scientific director of Germany's Center for Travel Medicine (CRM).
Symptoms include headache, nausea, fatigue and dizziness.
Depending on the region, the number of affected climbers can be quite high.
According to the CRM, as many as 21% of climbers develop symptoms in Nepalese high mountain areas, and from 45 to 75% on Kilimanjaro.
“Altitude sickness is a serious but avoidable problem,” remarked Jelinek, the cause of which is lower oxygen levels in the ambient air: at 5,000 meters they're only about half those at sea level.
“The most effective way to prevent it is to take precautions,” he said.
He recommended that mountaineers plan their climbing tour carefully, get travel medicine advice before setting off and critically examine bookable tours - also with an eye to the ascent profile of the climb.
To help your body adapt to lower oxygen levels, Jelinek said it's good to prepare with high-elevation day treks so long as you sleep at lower elevations afterwards.
Train high, sleep low, in other words.
Rest for a day after every elevation gain of 1,000 meters at the latest.
Beginning at an elevation of 2,500 meters, the elevation at which you sleep shouldn't increase more than 300 to 600 meters daily.
And be sure to drink sufficient fluids, since dehydration can aggravate altitude sickness symptoms.
Increased breathing and heart rates are a normal reaction when acclimating to mountain ascents and have no pathological significance, according to the Institute of International Health at Charité University Hospital in Berlin.
Experts there said signs of an early stage of altitude sickness are headache, nausea and vomiting, fatigue, loss of appetite, dizziness and difficulty sleeping.
If you have symptoms such as headache or dizziness, which usually occur six to 12 hours after quick climbs at elevations over 2,000 meters, you should stop your ascent. The symptoms then typically disappear within one to three days.
If they don't, or your condition worsens, you should descend immediately. The symptoms generally abate after an elevation drop of 500 to 1,000 meters, the health experts said.
In severe cases, you should receive medical assistance if possible. Transport to lower elevations is then imperative. At worst, altitude sickness can be life-threatening, causing your lungs to fill with fluid or your brain to swell.
The experts also pointed out that certain medications, such as acetazolamide and dexamethasone, can help prevent symptoms of altitude sickness. Both are available by prescription only.
