I've never been to altitude before. What should I worry about in going there?

Nothing ! Going to altitude is a pleasurable experience providing you don't ascend too quickly. Do pay attention to changes in your functioning; monitor how tired you are and your recovery time from an activity. If you're not doing so well, don't raise your sleeping altitude until you are feeling better. If this doesn't work, go down to the altitude at which you first noticed any symptoms of altitude illness.

Is good physical fitness protective for altitude illness ?

No. Individuals may experience more altitude illness because they can go higher more quickly. Fit people find it easier to enjoy activities at altitude. They should not try to compete with high altitude natives such as Sherpas, who are in their element.

What is a good pace at altitude ?

One that does not exhaust you allows you to walk all day without extreme fatigue. A common beginner mistake is to walk too quickly and make frequent rest stops. Follow a rate of activity that does not require you to rest every fifteen minutes or half an hour. Learn the rest step for climbing: Advance your foot, and after placing it on the hill, before bearing weight on it, rest briefly. Then shift your weight and repeat. Synchronize your breathing with your climbing. Whether you're low down on steep ascents or higher, inhale on one step and exhale on the next. At extreme altitudes, take two or three breaths with every step at a rhythm that you can continue without stopping to rest. Repeat a verse of a song or a mantra in synchrony with your feet and lungs. Vary the pace depending on the trail and conditions of the climb. Speed up on easier sections, slow down on more strenuous. Begin the day's journey slowly, and as the muscles and cardiovascular system have "stretched", increase the pace. Toward the end of the day, slow down as the machine is more fatigued.

The other less common mistake people make is to walk too slowly, which is fatiguing in itself. Walk at your pace and not that of the person in front of you. A certain level of discomfort in exercising at altitude (and at sea level) must be tolerated.

What is the safe daily rate of ascent at altitude ?

No rate is safe for all. Published itineraries for groups going to high altitude on commercial to private trips will be too fast for perhaps 10 to 20 percent of the participants. Not raising the sleeping altitude more than 1000 feet (300 meters) a day above 10,000 feet (3050 meters) is offered as a safe rate of ascent if a stopover day is thrown in every 2000 or 3000 feet (610 or 910 meters). On the stopover day climb as high as you like but return to the previous night's altitude to sleep. Some people will find this too fast, so if they get AMS, they should slow down.

If I have altitude illness, does that mean that I will never be a successful high altitude climber?

No. It is OK to have altitude illness. Many Everest summiteers have had HAPE and HACE. It is not OK to die from altitude illness, which is a totally preventable condition that if diagnosed and treated early enough results in complete recovery.

I had HAPE at 14,000 feet (4270 meters). Does that mean I will always get it at this altitude ?

No, it varies with each excursion to altitude. If you ascend slow enough, you will not get it.

I've tried to climb Mount Rainier numerous times and find that I always can't go higher than 12,000 feet (3660 meters). Is there a ceiling for certain individuals at altitude?

Perhaps. Try acetazolamide before and during the ascent, and spend an extra day or two at the lower camp before attempting the summit.

Are men more likely to get altitude illness than women?

More victims are male, but more men go to altitude. Women tend to breathe more at altitude than men suggesting they may be less susceptible to HAPE. Menstruation in women is probably not a risk factor for getting altitude illness. Also they are less macho and more silent and goal oriented. Men and women are equally at risk.

Should I take birth control pills at altitude ?

Yes, if you need them for contraception or menstrual regulation to prevent excess bleeding. There is no evidence that it is harmful to take them at altitude, although on theoretical grounds, estrogen-containing oral contraceptives may increase the risk of blood clots higher. Certain individuals with a history of blood clots or a family history of clotting problems (i.e., having a susceptible genetic makeup) may be at an increased risk for blood clot complications. These are more likely to show up in the first year of oral contraceptive use. So beginning the estrogen-containing drugs with no previous history of use and going to altitude soon after is probably risky.

Is consuming alcohol bad for acclimatization at altitude ?

Probably. The early symptoms of altitude illness resemble those of a hangover. By imbibing, it may be difficult to tell whether you are suffering from altitude illness or from the effects of alcohol. Alcohol depresses respiration during sleep. Avoid alcohol until you are well acclimatized and not going higher.

Can judgment be impaired at altitude ?

Yes. Psychometric studies on individuals at high altitude show a loss of performance.

I'm going to altitude with a commercial group that is carrying a hyperbaric bag. Doesn't that lessen my chances of having problems with serious altitude illness ?

No. It is unclear whether a group carrying a hyperbaric bag is less likely to have problems. Among trekkers to high altitude destinations in Nepal, those traveling independently are less likely to experience a fatality resulting from altitude illness. Such people may be more flexible in their schedules and less likely to be influenced by peer pressure. The bag may not change that (see Shlim and Gallie 1992). Aggregate statistics do not distinguish between groups with experienced, competent leaders and those without. Travelers with commercial groups should assess the competence of their leaders as there are no regulatory standards.

I feel myself suffocating and not sleeping well at altitude. I catch myself falling asleep and suddenly waking up and feeling claustrophobic in the tent. What should I do ?

Avoid sleeping pills and take Acetazolamide at bedtime.

I live at sea level. Are my chances of getting AMS greater than someone who lives at 5000 feet (1525 meters ) or higher ?


What is the finger test for altitude ?

The finger test is a term refereed to in measuring the oxygen saturation of the arterial blood using a device called a pulse oximeter in which a sensor is attached to the end of a finger. The reading represents the percentage of hemoglobin that is saturated with oxygen in the arterial blood. As one climbs higher, less oxygen is available to fill the oxygen-binding sites on the hemoglobin molecule. There is an expected range for oxygen saturation in the normal individual at particular altitudes and in the person that is acclimatized to that altitude. Newcomers will have lower readings that will increase after a stay at that altitude. Individuals with HAPE will have lower readings. At sea level the normal reading is 96 percent or above, while at 15,000 feet (4570 meters) it is around 86 percent, dropping to about 76 percent around 20,000 feet (6100 meters). At the summit of Everest 29,029 feet (8850 meters )it drops to approximately 58 percent.

Some groups at altitude carry a pulse oximeter (today's models are small and light in weight) in an attempt to gauge how well individuals are acclimatizing and hoping to diagnose HAPE if necessary. Cold fingers as well as exercise can give falsely low readings. And readings may be normal with carbon monoxide poisoning. I feel carrying such a device is unnecessary, but in these technological times, a number of groups do.

Up high I lose all my sexual drive. Is this normal ?

Yes, although others report an increased libido, and erotic hypoxia.

17. I'm going to altitude. Should I take Acetazolamide to prevent altitude illness ?

No, unless you have predictably and repeatedly had altitude illness before and are contemplating another venture up high, or if you are on specific time-cramped itineraries or flying to high-altitude destinations such as Lassa, Tibet. Use of this agent in our pharmaceutical culture is becoming more common. One individual said, "I feel totally diamoxalized" on a 5000 – meter pass. Consider whether this is how you want to remember your affair with thin air.

At what altitude should I start to take Acetazolamide for preventing altitude illness, given that I have decided to take it ?

Just before any abrupt increase in altitude above 8000 feet (2450 meters) beginning the day you ascend.

What dosage of Acetazolamide should I take when using it for prevention ?

Take 125 mg. (half a tablet) twice a day, morning and night, if you are ascending slowly to modest altitudes. On the other hand, if you are being transported to significant altitudes, double the dose.

Can taking Acetazolamide mask the symptoms of altitude illness ?


I'm allergic to sulfa drugs. Should I take any other drug for preventing altitude illness ?

Allergic reactions to Acetazolamide are rare. People ascribe many different symptoms of allergies. If you are supposed allergy to sulfa drugs, consults your doctor. Consider taking a test dose of acetazolamide under the controlled clinical situation to determine whether or not have a true allergy. Dexamethosone is not recommended for preventing altitude illness in routine situations. Consider it for rescue situations to high or extreme altitude requiring rapid ascent by air transport. Take nifedipine if you have had HAPE before.

Will I get rebound altitude illness if I stop taking Acetazolamide?

No It actually aids acclimatization. Stopping dexamethasone, the other prophylactic, can result in rebound.

I read the package insert on acetazolamide. So many side effects are listed. Which ones are commonly reported at altitude ?

Every side effect ever reported is listed in the manufacturer's statement. Tingling of the lips, fingers, and toes is common as well as urinating more often. While it changes the taste of carbonated beverages, many people don't report this. On rare occasions people do have serious reactions.

Acetazolamide, by your accounts, is a great drug. Why not recommend everyone take it at altitude ?

I believe in avoiding drugs if there are equally effective and potentially safer alternative such as slow ascent for altitude. If you believe in a pill for every ill, you may want to act differently. Many people find the tingling that it causes annoying.

My doctor suggested I take a sleeping pill since restful sleep is said to be hard to come by at altitude. Is there anything wrong with that ?

Yes, sleeping pills were routinely prescribed by doctors a few decades ago to ensure a good sleep at altitude. Because they depress respiration, a critical factor in acclimatization, taking sleeping pills, sedatives,or tranquilizers is generally not recommended. That said there are some studies on agents such as temazepam that imply that they do not depress respiration at altitude. Temazepam stays in the blood a long time, and could have and effect on energy levels and motivation. On a climb to 7500 meters that I participated in, two individuals who took a similar drug at altitude were very sluggish the next day, and one climber did not have enough drive to get to the summit. Very short-acting agents have not been studied, but they might also be effective.

Now that there is a drug to treat HAPE, isn't altitude illness a less serious problem ?

No. Nifedipine has received attention because of its reported ability to help symptoms of HAPE. It has proven very useful in preventing HAPE on rapid ascents of Monta Rosa in the Alps and in studies done by Oswald Oelz and Peter Bartsch, among others. The treatment effect does not appear to be as dramatic in HAPE that comes on during slower ascents in the Himalaya. People have died, presumably from HAPE, after taking nifedipine.

Aspirin has been touted as panacea for extending life and preventing heart attacks. Should I take it at altitude ?

Maybe. If you take it on a regular basis at home, then continue taking it at altitude. Whether or not aspirin really is beneficial in sojourners to altitude is unknown. There are theoretical grounds for taking it, at least at extreme altitude (above 18,000 feet, 5590 meters), but it doesn't make sense for everyone at altitudes below that. Discuss this with an altitude-savvy doctor.

What about taking furosemide and other potent diuretics at altitude ?

Don't. Initial studies supported their use in preventing altitude illness, but they have not been repeated successfully to justify using them at present. Significant side effects, including dehydration and fainting, result from their use. Faced with a serious case of HAPE, most clinicians who carry the drug will likely administer it.

Do antacids prevent altitude illness ?

No. Experiments conducted to test the hypothesis did not show any effect

My friends are trying to get me to take dexamethasone whenever we climb above 14,000 feet (4270 meters). They say it makes them feel great and perform better. What do you think ?

Some people feel dexamethasone, a steroid, is a wonder drug. The controlled, double-blind studies did not show it to be so wonderful. It does prevent AMS but does not aid acclimatization, as Acetazolamide does. Acetazolamide both prevents and treats AMS. Steroids can cause euphoria or depression. In addition, if your pills were to get lost or avalanched off, you would be in dire straits. The side effect profile does not warrant even thinking of using this drug routinely. Competitive athletes are disqualified for using this pharmacologic agent; should climbers be any different ?

In early expedition accounts, climbers carried amphetamines and other stimulants to help when something bad happened or when they were extremely exhausted. Is this a good idea?

The above points about "doping" with steroids apply here. Use of stimulants is hazardous, especially in critical situations requiring good judgment. Studies at low altitudes demonstrate users having poor judgment and being more likely to have a serious automobile accident. Amphetamines have caused death through a variety of mechanisms and produce tunnel vision, which can be hazardous in mountain environment. Modafinil, which has been touted as a modern drug to ward off sleepiness, appears to be difficult to self-monitor (how well you perform) after sleep deprivation. These agents might increase pulmonary artery pressure and lead to HAPE, but there are no studies of any such agents at altitude. The so-called Triple D (dexamethasone, dextroamphetamine, and Daimox) is used by some climbers, just as heroin used to be taken by famous surgeons. I used to carry dextroamphetamine in my medical kit years ago and never used it. Now I don't carry it at all. Use of such agents has been presumed to be the cause of death in some climbers when it affected their judgment, causing them to do something stupid. One climber described having to consciously prevent himself from flying off the mountain while on amphetamines. My sense is that there is considerable use of these agents and likely considerable harm, including death as a result. I speculate that if climbing at altitude was safe, there would be a different population who did the activity. Adding other potential risks may not matter that much for some.

Is there a special diet that is to be recommended at altitude ?

While on theoretical grounds, a low fat, high carbohydrate, low salt diet could be best, there are few dietary options for those visiting high altitudes and eating locally produced foods, which usually include meat and potatoes. Eating very salty foods has been reported to increase the risk of altitude illness. A good appetite is a sign of adaptive acclimatization at altitude but can't be relied upon to exclude altitude illness. Eat what appeals to you and is easy to prepare. The widely touted high-energy foods may not be palatable up high and thus not get eaten. Thin people welcome some fat in the diet to help keep insulation from melting away. Garlic may be beneficial.

Will keeping well hydrated prevent altitude illness ?

Hydration by itself will probably not prevent altitude illness. One can easily get dehydrated at high altitude because the ambient air is so dry, and activity increases insensitive loss. Dehydration may increase the risk of developing altitude illness. Drinking enough water requires effort at altitude –melting snow or purifying a liquid source – but trip leaders report that keeping well hydrated is an important factor for success. In some parts of the world people are advised not to drink water during the day's activities but to hydrate before and after. The timing of hydration has not been adequately studied, but I advise frequent hydration. Like any advice, it can be overdone and people have died from drinking too much water.

Soup mixes, drink powders, instant eggnog, cider, cocoa, and herbal teas make water more palatable and easier to consume in quantity at altitude.

All this talk about hydration when the syndromes to be feared most are excess water in the brain and the lungs. Shouldn't we be drinking less?

No. The waterlogging of the brain or lungs is not a problem of water overload but of leakage from spaces where water is to spaces where is shouldn't be. The lack of oxygen in cells causes this, not an excess of water.

I'm incredibly thirsty at high camp, but I lost my water purification materials. Can I drink the water here anyway ?

Yes. Treating significant dehydration when it occurs takes precedence over the cleanliness of the water source. Melted snow is safe enough as are mountain water sources without a population center or animals nearby. There are heavily trafficked areas such as the staging area on Denali or the foot of the Khumbu Icefall, where I advise caution. Do not wait for thirst to signal the need to drunk as this mechanism may not work well up high.

I went on a trek to altitude in Nepal and wasn't feeling well. I don't recall the details, but a helicopter was called and I was evacuated. When I arrived in Kathmandu, I felt perfectly fine. I would not be liable to pay the rescue bill, since I really wasn't sick there. Isn't it up to the agency and the trek leader to pay for it ?

You should gratefully pay for being alive. Such common stories indicate the person had a form of altitude illness requiring descent that was promptly carried out resulting in a rapid response and a survivor. The leader should be thanked for exercising conservative judgment, which is prudent at altitude. There are too many situations where people waited too long, and bodies were evacuated. Ask your travel agent about rescue insurance before you leave.

I feel so awful, but it's getting dark. Can't I wait until morning to get down ?

No. You are faced with a difficult decision. There are too many cases where a corpse was found in the morning to even suggest waiting.

I walked slowly from Lukla to Namche Bazaar, and I still got altitude illness. What should I do differently on my next trip to altitude ?

It is not the speed of your walking, but the amount that you raise your sleeping alftitude that counts. Sleep at Lukla the first night and at Jorsale the next before ascending to Namche. Do not carry a loaded pack the next time to limit exertion, as those who exercise at a more rapid rate may be more inclined to get AMS and HAPE.

Couldn't my breathing condition, cough, and fever be pneumonia at altitude ? Shouldn't I wait to see if the antibiotics work ?

No. It's best to treat all suspected cases of pneumonia at altitude as if they were HAPE and add an antibiotic to the regimen.

My Sherpa, Lhakpa, has rapid breathing, lethargy, and a cough. A high altitude native, he couldn't have HAPE, could he ?

Yes. He could have HAPE and will need to be treated as any other person with the same symptoms. Some lowlanders in Nepal call themselves Sherpa to get the business.

Could my diarrhea be a symptom of altitude illness ?

Unlikely. Your water losses will be greater at altitude so hydrate more.

I've had a cold that started before coming to altitude. Now the trip leader is concerned that I have HAPE. My symptoms seem the same. Could she be right ?

Yes. Others are often more capable than you to notice changes in signs of altitude.

The trek leader listened to my lungs and told me she heard rales. Does this mean I have HAPE ?

No, rales (a particular sound, also called crackles, heard with a stethoscope on listening to the chest) are common at altitude and do not by themselves mean a person has HAPE. If crackles persist after several deep breaths, HAPE or pneumonia could be present. Look for other signs and symptoms.

My companions tell me I have HAPE. I have descended a thousand feet to where I first began to feel the extreme shortness of breath. Now I feel a little better. Shouldn't I spend the night here and see how I feel in the morning ?

No. Such a scenario has proven fatal. When you have serious symptoms of altitude illness, you should descend to below the altitude at which you first had any symptoms of altitude illness, even mild ones. You may not improve significantly before doing so.

Everyone in my group, except me, got up several times last night to pee. I feel fine, what should I do? Drink more?

Yes. you may well be dehydrated. Check for other symptoms of altitude illness as well, and act accordingly. Alert your companions that you are not urinating as much as they are. Ask that the watch you for possible signs of developing altitude illness.

We were all short of breath ascending to the high point. Why all this fuss about me, continuing to be short of breath ?

It seems you didn't improve with rest, which is the key point. Those short of breath with activity should quickly get better with rest.

I've climbed ten fourteen-thousanders in Colorado. That means I'll have no problems with altitude going to Everest Base Camp ? Right ?

Unfortunately not. Response to altitude is variable from person to person, and for an individual from time to time. There are many Everest summiters who have since had serious symptoms of altitude illness at much lower elevations.

I'm a doctor. I know what's going on, and I do not have altitude illness !

The mortality rate for doctors at high altitude is disproportionately greater.

I notice that George in the next tent is short of breath all the time, even when resting. He eats very little at meals. He says he's fine. Should the rest of our group be concerned or take action ?

Yes. It could be altitude illness denial. Go through the protocol and act accordingly, or get George down a few thousand feet and see if he improves.

Sandra has been getting worse at altitude for the last few days. The leader says it's because she has the flu, is dehydrated, and hasn't been practicing her meditation exercises properly. What should we do ?

Act on humanitarian grounds and get the leader to agree to have her descend without delay to see if she improves. If the leader refuses, consider going against the decision.

Jeremiah died of presumed altitude causes in Dolpo. Shouldn't we do all we can to get the body back to his home ?

No. Recognize how difficult it is to transport a corpse on carriers in many countries, impossible in some. Consider a proper traditional disposal of the remains according to the local customs. You will need to deal with local authorities and other survivors. Write down what happened, photograph everything, and save as many personal effects as possible.

I'm pregnant and want to go on a high altitude adventure. Is this wise ?

We do not know about the effects of altitude on pregnancy to either the lowlander mother or the fetus. If there was a mishap in the pregnancy outcome that could be attributed to altitude, would you blame yourself? Then limit altitude exposure to 10,000 to 12000 feet (3050 to 3660 meters) and ascend slowly, so you don't seriously compromise the amount of oxygen carried in the blood. A miscarriage in a remote area would be scary for most women.

Should I take my children to high altitude with me ?

As more and more parents venture to altitude, children accompany them to altitudes of 18,000 feet (5500 meters) or so, without ill effect. A leisurely itinerary is important. Children aged three and seven have hiked to the top of Kala Pattar (18,450 feet, 5620 meters). A three-and a half year old was successfully treated for symptoms of lethargy in a hyperbaric bag. It is difficult to identify symptoms and signs of altitude illness in children. Altitude localities are cold and remote, making evacuation worrisome. Consider any questionable behavior at altitude to be altitude illness. Descend quickly and few problems should result.

Does it make sense to postpone the trip to altitude for a few years until we know more about the scourage of altitude illness ?

We know what we need to know to prevent deaths from altitude illness.

I have heart disease and a number of other medical problems, and I have had coronary bypass surgery. I take medicines for high blood pressure. My doctor tells me I shouldn't even think of going to Khumbu to see Mount Everest, though it has been a lifelong dream of mine. Should I listen to him ?

The answer depends on the benefits that you will gain from attaining your goal, weighed against the increased risk of being in a place where full-service emergency care is not minutes away. The chance of dying from heart disease does not appear to increase at altitude. If you decide to go, find a doctor who can advise you in modifying your blood pressure drugs at altitude if necessary. Travel with a group that includes altitude savants.

Are individuals with migraine headaches more inclined to migraine headaches at altitude ?

Perhaps. Some people report an increased frequency, others greater severity with symptoms not seen lower down. Treat them as any other headache at altitude, checking for ataxia, rapid breathing, and so on. Don't ascend, and try pain medicine if there are no ominous findings.

Himalayan Rescue Association Nepal

Dhobichaur, Lazimpat (North Gate of the Royal Palace)
P.O. Box No. 4944,
Kathmandu, Nepal
Phone: +977-1-4440292 / 4440293
Fax: +977-1-4411956
E-mail : hra@mail.com.np

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