When you ascend to altitudes greater than 2500 metres your body must adapt to having less oxygen and in the meantime you may develop altitude sickness. In order to prevent serious altitude sickness you must allow for acclimatisation, which is a gradual process that allows the body to slowly get used to the lower levels of oxygen in the air and as an end result to deliver the necessary amounts of oxygen required by the cells to function properly.

Different people acclimatise at different rates, it has nothing to do with age, gender or fitness, so it is not possible to know in advance how you will react to the altitude, especially given the fact that it varies with each person for every exposure, meaning that even if you have been fine at high altitude on previous occasions, it doesn’t mean that this will always be the case. Of course if you were born and live at sea level you are likely to be more sensitive to the altitude than others, although there are no strict rules. It is important that you do not pay too much attention to other travelers’ advice, because what may be true to them may end up being a completely different scenario for you.

The best strategy is to take your time and drink plenty of water (a minimum of three litres a day), because the body experiences diuresis at altitude, meaning that you urinate more and lose fluids, and thus increasing your water intake is a vital factor in promoting well-being. Drinking coca tea and chewing coca leaves can also help. Eating light, low in salt, non-greasy, carbohydrate-rich meals, abstaining from alcohol and drinking coffee in moderation are also recommended.

The risk increases with faster ascents, higher altitude and greater exertion. To allow your body to adjust, whenever possible we have structured our treks with slow ascents to allow for acclimatisation, but unlike in the Himalayas, altitude gain is often rapid and not gradual in the Andes. For that reason we strongly recommend that you spend a minimum of two days in Huaraz before setting off on your multi-day trek. During that time it is essential that you do a couple of day hikes that bring you gradually to higher altitudes, the idea is to “climb high and sleep low” in order to prepare yourself to sleep at higher altitudes during your multi-day trek. It is important that you do not go too high too fast, so aim to go below 4000m during the first hike and to around 4500m during the second hike. People who are more sensitive to the altitude will need longer to acclimatise, so may require to do three acclimatisation hikes, or more. If you suffer from jetlag or exhaustion from travel, it is wise to allow one day for complete rest before undertaking any physical activities.

During the acclimatisation process, you may experience some of the following symptoms: headache, tiredness, dizziness, disturbed sleep, loss of appetite, nausea, shortness of breath, cough, palpitation, swelling of the hands and face. These symptoms may not indicate the onset of severe altitude sickness, and do not necessarily mean you should not continue.

All QUECHUANDES staff have considerable knowledge of altitude sickness and all QUECHUANDES guides are highly experienced in the mountains and have extensive first aid training, so we encourage you to tell us or your guide of any symptoms so we or they can keep an eye on you. The only cure for altitude sickness is to descend. Please note that we and your guide have ultimate responsibility and may ask you to not participate in a trek or to descend (meaning leaving the expedition) if symptoms persist. Altitude sickness must be taken seriously as it can be life threatening when severe. As a result we do not accept non-acclimatised individuals to participate in our treks, as this would mean potentially putting your health at risk and inconveniencing other members of the group. When signing up to any QUECHUANDES trip you agree to these conditions.

Acetazolamide (Diamox) is probably the best drug to consider to prevent altitude sickness, however we would not advise you to take it unless you have predictably and repeatedly had altitude sickness before, or if you are on a specific time-constraint itinerary that won’t give you enough time to acclimatise naturally. We believe it is best to acclimatise naturally whenever possible and to avoid this drug, as a gradual acclimatisation program is an equally effective and potentially safer alternative. Diamox is a strong medicine that has many side effects and should not be taken by those who have a sulfa allergy, therefore it is important to have it prescribed by a knowledgeable doctor. It is important to take the correct dose. Side effects include tingling of the lips, fingers and toes, and frequent urination as it acts as a diuretic, so it is important to take even more fluids. To prevent altitude sickness, start taking Diamox 1 to 2 days before you arrive in Huaraz. Continue taking it while you are ascending and for at least 48 hours after you have reached your final altitude. You may need to continue taking this medication while staying at high altitude to control your symptoms. If you develop severe altitude sickness, it is important that you descend as quickly as possible. Diamox will not protect you from the serious effects of severe altitude sickness. Do not increase or decrease your dose or stop using this medication without first consulting your doctor.