Maya Calderon
Altitude is often misunderstood and mismanaged. Most people either over prepare for its effects (paying big bucks for pointless training), or they fail to prepare at all (hitting the wall on day two of their first high country trip). It is a variable that requires understanding of what acclimatization is, what it actually feels like in your body, and what methods are actually of value in hiking at high altitudes as opposed to what is merely a placebo.
Since sharing this piece of writing, I have found that it has helped several people plan for their first high-altitude trip. As someone who has spent a lot of time traveling above 4,500m, and once to 5,500m, the lessons I have learned slowly along the way can now be shared with you in this more practical guide to acclimatizing to high altitude on your trip.
What altitude does to the body
With altitude, the amount of oxygen in the air decreases. While at sea level the oxygen partial pressure is approximately 21 kPa, at 3,000 meters it is approximately 14 kPa and at 5,000 meters it is approximately 11 kPa. The body is very clever at coping with this decrease in oxygen in the air by increasing your breathing rate and heart rate and within a short amount of time, your body starts to produce more red blood cells in order to more efficiently transport the oxygen in your blood.
Acclimatization takes days to develop. Try to acclimatize your body to 4,000m in one day and you can rest assured that a few days later you will be hospitalized with some form of high altitude illness. Plan your trip before it becomes a catastrophe.
What it actually feels like
The realistic symptoms at altitude, in roughly increasing severity:
Arms and legs can feel as if they have been pumped full of extra heavy water and climbing the stairs of a number of floors becomes a grueling workout of strenuous physical effort. This is normal for all people after their first 24 hours at an elevation of 2,500m or higher. Dyspnea (symptoms of being out of breath) with physical activity. (An example of this is having to pant while climbing a flight of stairs.) Symptoms of this sort occur in everyone after 24 hours at elevations of 2,500m or higher. They begin to resolve 24 to 48 hours after arrival. A mild headache: a dull persistent ache that can be more apparent in the evening. A headache above 3,500m is quite normal. Poor sleep. Usually it’s a problem getting to sleep in the first place, or you’re waking frequently during the night and have very real dreams when you do finally fall off to sleep. If you’re experiencing poor sleep at altitude it’s always common above 3,000m. Mild nausea or loss of appetite: This is where people say that they haven’t got an appetite or they just don’t feel like eating. This starts to become quite common from around 4,000m.
The above are the normal acclimatization effects of the body on the mountain. They generally subside with rest, at the same altitude, over a 24-48 hour period. I have been on this trip three times and the middle trip was by far the cheapest.
What it should not feel like
The symptoms that mean stop and descend:
Severe headache that does not respond to fluid and ibuprofen. Vomiting. Not just nausea; actual vomiting. Confusion or slurred speech. Loss of coordination. Walking like you are drunk. Shortness of breath when at rest. Persistent cough, especially with frothy or pink sputum.
Severe headache (despite plenty of fluid intake and I.B.) , Vomiting, Confusion, Slurred speech, Loss of coordination (making difficult walk), Breathlessness at rest, Coughing (particularly with frothy / pink sputum). These are early warning signs of life-threatening HACE (High Altitude Cerebral Edema) or HAPE (High Altitude Pulmonary Edema) – both conditions require immediate DESCENT to lower altitude – not medication.
The ascent schedule that works
The standard guidance from mountain medicine:
As a guideline for mountain climbing, below 2,500 meters healthy adults do not need to take any special precautions. Above 2,500m consider sleeping at an altitude that is 500m below your highest altitude for the day. Every 1,000 meters of ascend, put in a rest day at 3,000 meters. The higher the altitude the more conservatively you should climb. At 4,000 meters climbing 300 meters of sleeping altitude will drastically reduce symptoms of acute mountain sickness. Above 4,000m a sleeping altitude of 300m is even more prudent as it will decrease the incidence of even mild symptoms in most climbers significantly.
Climb high, sleep low. Hike to higher elevation during the day, then return to lower elevation to sleep. Your body can acclimatize to the higher elevation in which you are hiking during the day, without being hindered by the need to recover at lower elevation where you are sleeping.
The habits that help
Hydrate, more than you think. This is a commonly misunderstood aspect of high altitude travel. Above 3,500m one should drink between 4 to 5 liters per day. Dehydration increases the severity of all symptoms of high altitude. Eat lots of Carbohydrates. Since your body is in an abnormal state at high altitudes your body will start to use carbs for energy instead of fat. They will be the preferred fuel when oxygen is in short supply. Don’t drink alcohol for 48 hours after arriving at altitude. The effects of altitude combined with alcohol are far worse than the average hangover. Sleeping with your upper body at an incline can help with breathing as well as stopping oxygen from dropping at night. Descansen com as pernas levantadas; isso ajuda muito para dormir bem em altitudes e para respirar bem também.
The medications
Two medications are commonly used:
Acetazolamide (Diamox) – an altitude medication. Useful for serious cases of high altitude sickness. It will start to work in 24 hours and should be taken before arriving at high altitude. The side effects are excessive urination and the fingers may feel tingling. Speak with a doctor before bringing this. Dexamethasone: This is an even more powerful medication for serious cases of altitude illness. It is used as treatment, not prevention.
While there are two medications used to help alleviate the effects of high altitude, they are NOT substitutes for acclimatization. Both of these medicines are used as aids to help your body acclimatize faster, and should be treated with respect. Remember, confirm the day before you depart for high altitude, not the morning of.
The fitness question
Fitness is important in terms of the effort to ascend in high altitude but does not protect against Acute Mountain Sickness (AMS). The fittest of cyclists would still need to acclimatize at high altitude. However, there are cases of very fit individuals suffering from worse AMS than their less fit traveling companions, who may be pushing them to ascend in order to reach their destination and then ignoring early symptoms of AMS in order to continue their trip.
Aerobic training enables someone to move at altitude in the best possible manner; in no way does it enable someone to go up at high altitude without acclimatizing properly. Trekkers must plan their schedule as if they were less fit than they actually are.
The first-trip recommendation
For a first trip to altitude above 3,500m:
Plan your trek so that it has built-in acclimatization days – such as found on most commercial Everest Base Camp treks or other higher altitude treks, but few independent itineraries. Arrive at your trailhead one day prior to your trek and spend the time at moderate elevation (2,500 – 3,000m). This will allow your body to begin acclimatization for your impending high altitude adventure. Add an extra rest day to your itinerary to allow for altitude sickness should it occur. Small bottles of ibuprofen and a thermometer for monitoring a sickness of high altitude are things that you should take with you on your trip. Report to your guide or fellow trekkers any signs of sickness. It is far more common for a trekkers to need to emergency descend due to hidden illness than for them to admit to their guides and fellow trekkers that they are not feeling well.
The honest summary
High altitude hiking is one of the most rewarding kinds of mountain travel. Firstly, the landscapes above 4,000m are exceptional, and offer scenery that is far beyond other mountain environments at lower elevations. Secondly, high altitude hiking requires a lot of effort, therefore for most people, it demands a lot of attention as they progress slowly up a mountain. This attention given to each step, to each breath, to each headache and to each bit of fatigue creates an opportunity for a really deep and rewarding experience.
The respect for altitude that once kept these places to themselves has, in the end, made them accessible to us all. High altitude hiking is one of the most rewarding kinds of mountain travel. There’s nothing quite like the landscapes, the effort, the slow traveling, and the vast scales of high altitude places. Done right, they are some of the most memorable experiences of any mountain travel.
