4 phenomena accompany altitude:

- The diminution of the atmospheric pressure. At sea level, the pressure is of 760 mmHg, in Bolivia it is at an average of 415 mmHg.
- The relative reduction of Oxygen.
- The drop in temperature. At altitude, the temperature drops 6.5 degrees with every 1000 meters gained.
The physiological manifestations are a rise in the respiratory rate, of the heartbeat and a rise of the oxygen transporter, the red blood cells, to compensate for the lack of oxygen.
- The intensification of the solar radiation.

WHO IS AFFECTED BY ALTITUDE?

Generally, it is considered that altitude sickness (or “sorojche”) affects about 15% of people at 2000 meters above sea level, 60 % at 4000 meters, and everyone at high-altitude (over 5000 meters). Unlike seasickness, it can affect anyone, and age is not a risk factor.

WHAT ARE THE SYMPTOMS?

"Acute mountain sickness" is a reaction of the body’s lack of acclimatization to altitude due to a lack of oxygen. These troubles usually occur from 4 to 8 hours after arrival at altitude, and generally above 3500 m. The symptoms of these troubles include:
- Headaches, a feeling of exhaustion and rapid breathing, in most cases
- Insomnia in 2/3 of the cases
- Loss of appetite in 1/3 of the cases
- Nausea in 1/3 of the cases

These symptoms, frequent and normal, disappear generally on their own, or with the help of aspirin, after a few hours spent at altitude. Altitude sickness can also diminish urine volume, accompanied by hands, ankles and face edema. In this case the opinion of a specialized medical doctor is mandatory

CONTRAINDICATIONS TO THE PRACTICE OF TREKKING OR MOUNTAINEERING

- Vascular insufficiency
- History of respiratory compromise
- Epileptic seizures and previous neuro-surgery
- Illnesses necessitating repeated injections such as insulin–dependant diabetes
- Unstable heart diseases
- Some blood disease
- Acute mountain sickness, cerebral or pulmonary edema during a previous trip

PREVENTION

While still in your country, we suggest you visit a medical practitioner to detect any medical condition or weakness. We also recommend that you exercise regularly before your trip to South America, especially if you are considering trekking or mountaineering. Hiking (if possible at altitude) or swimming will help you acclimate faster.
In Bolivia for instance, it is mandatory to respect a period of acclimatization before attempting any Andean summits. We advise you to spend a few days in La Paz or to visit Lake Titicaca (trek on the Isla del Sol), ideal places for short stays.
We recommend you drink profusely and especially mate de coca (infusion of coca leaves, at no risk…).

OUR COMMITMENTS

We particularly make sure your programs are progressive. For all our mountaineering / trekking tours, a prior (and mandatory) acclimatization of a few days is planned.
The rare cases of serious acclimatization problems occur at the beginning of the stay and we see about one every two years.
In such case, the return to the closest town is immediate.

OUR ADVICE FOR TREKKING AND MOUNTAINEERING

Here is some advice to follow during a trek or an ascent:
- Climb slowly and progressively. We suggest that above 3500 meters above sea level, you do not ascend more than 700 meters from one night to the next. Starting from 3500 meters, for example, you can climb a pass at 4500 meters (+1000 m) if you sleep lower (for example at 4000 m, the altitude difference between this bivouac and the prior is then of only 500 meters).
All of our trekking and mountaineering programs are designed to respect this rule.
- To sleep well, once at the bivouac, climb above the camp about 200 to 300 meters without your backpack, try to stay about an hour and return to camp.
- Do not exert yourself (no giant steps, jumping or running)

- Remember to hydrate. Warning: purify the water or you will fall victim to other ailments of a gastric nature.
- Eat well. A well-balanced breakfast will give you the energy necessary for the efforts you have to expend. Everyday, you will receive trekking snacks (cereal bars, dry fruits, sweets).
- Change into dry clothes when you reach your camp.
- Stretch after each day’s hike to alleviate cramps and soreness.
- Be motivated! An ascent depends at 50% on your mental power.