AMS in Cusco

This will actually be my third post on this subject, but as new information comes to light, I do my best to update my posts. As altitude sickness or AMS can lead to more serious conditions, I thought that it was time to make a new post with updated information, and rather than refer back to my old posts or try and update them, I have decided to delete the information, and my old posts will now just link to this more current post.

Let me start this with some background information on myself, I am not a doctor, nor do I have any medical training, the information I will be sharing below is based on information found on the web (I will provide links), conversations with medical personnel, as well as some personal observations and opinions. Additionally I have been living here in the Cusco region and own and operate GringoWasi, which is a bed and breakfast located 30 minutes West of Cusco, and at about the same altitude, so some of my thought and opinions are based on our past guest experiencec.

So what is AMS? (Acute Mountain Sickness), aka altitude sickness or soroche. The short answer is, it is your bodies reaction to a reduction in oxygen, due to an increase in altitude. The CDC {1} describes altitude sickness as follows:

Symptoms are those of an alcohol hangover: headache is the cardinal symptom, sometimes accompanied by fatigue, loss of appetite, nausea, and occasionally vomiting. Headache onset is usually 2–12 hours after arrival at a higher altitude and often during or after the first night. Preverbal children may develop loss of appetite, irritability, and pallor. AMS generally resolves with 24–72 hours of acclimatization. .”

What are the symptoms of AMS and how do I prevent it? This is likely one of the most important questions that travelers should know the answer to, according to the most recent study done in 2010 {2}, 70.9% of travelers received no pre-travel advice on AMS prevention, and it also mentioned that trekkers aware of symptoms and prevention are less likely to develop AMS, so I would also think that tourist that are aware of the symptoms and prevention, would also be less likely to develop AMS.

The symptoms of AMS are generally considered to be Headache with one or more of the following additional conditions, following a recent gain in altitude;

  • Gastrointestinal symptoms
  • Fatigue &/or weakness
  • Dizziness/lightheadedness
  • Difficulty sleeping

Although difficulty in sleeping has been called into question in 2014 {3} as people often sleep poorly at altitude for common reasons other than AMS e.g. late night/early morning start, snoring, sleeping in a strange location, etc. A good guide or gauge for how you are doing can be the Lake Louise Scoring System (LLSS) {4} which has been designed to evaluate adults for symptoms of acute mountain sickness, This scoring system was used in the latest study in Cusco {2} and is commonly used for high altitude trekking as well. The LLSS is easy to use and interpret, and if you print a copy to bring with you on your trip, it will also give you a record of how you are doing , and let you know if you are improving each day.

The best way to prevent AMS is a slow accent, and according to the CDC {1}, when traveling from a lower altitude, it is not advised to ascend to a sleeping altitude above 9,000ft (2,750m) in one day. Once above the 9,000ft (2,750m) it is not advised to increase your sleeping altitude more than 1,600ft (500m) in one day. Other recommendations include

  • Using acetazolamide {7} to speed acclimatization, if abrupt ascent is unavoidable.
  • Avoiding alcohol for the first 48 hours.
  • Limit your activity to mild exercise for the first 48 hours.
  • Spending 2 or more nights at high altitude, 9,000ft (2,750m) or higher within 30 days of your trip can be useful.

What are the risks I will get AMS? This is likely one of the more difficult questions to answer as doing any realistic testing can be difficult, if not impossible, due to the large number of variables, but the most recent study {2} indicated that AMS was reported by 48.5% and 17.1% had severe AMS. Now a fellow poster on the Trip Advisor forums loves to point out when I share this information that the risk is likely higher as 30.5% of participants visited high altitude in the previous 2 months and 16.6% of participants used acetazolamide for prevention These of course are variables, but so is the fact that for the study, they were questioning the participants as they were departing Cusco, so the participants were asked to recall how they felt as much as 15 days prior to filling out the questionnaire. The symptoms for AMS are also the same as many other illnesses like food poisoning, severe fatigue, and a hang over, so some of those in the study that were determined to have had AMS, may have actually had some other condition.

I did contact one of the doctors involved in this most recent study to address these questions, as well as the fact that in our 4 years of running our bed and breakfast, we have maybe had only a couple of guests suffer from severe AMS, so based on what we have seen here, it would seem that the numbers would be much lower. The doctors replies to my inquiries were;

“You are right, there is no way to ascertain with a questionnaire several days after the illness if the symptoms were caused by AMS. However, in Cusco any traveler that develops severe headache + one or more of the other LLS symptoms in the first 48 hours should be regarded as having AMS in the absence of other symptoms like fever, sore throat, diarrhea, etc (this is the most prudent approach).”

“There are factors that may make subjects underestimate their symptoms (like … I just arrive to Cusco, don’t want to miss a second of my time at the doctors’ office) or overestimate them (they may recall them as worse than they really were or may not recall the date of onset well).”

Additionally the doctor also indicated;

“we have a prospective study in Cusco and we are finding a lower incidence of AMS, but not as low as the one you described.”

At this current date and time, I do not believe they have published anything, but I look forward to seeing new information. Until new data is published, I will just refer to the 17.1% risk of Severe AMS.

The risk of mild AMS is high as most people traveling to Cusco fly in, making it difficult to actually follow the recommended slow increase, which is why acetazolamide {7} is generally recommended for travelers coming directly to Cusco, and why some travelers opt to arrive and the travel directly to the Sacred Valley to acclimate. The good news if you are planing to travel directly to Cusco and not start in the Sacred Valley is that acetazolamide does appear to be effective, and most people function fine and do not feel the need to modify their plans even when effected by mild AMS, based on past guest experiences.

Worst Case – AMS can progress in to either HAPE {5} or HACE {6}which can be fatal if not treated, although it would appear that these are both uncommon conditions here in Cusco. I have tried to find some actual numbers on HAPE and HACE cases in Cusco, in a given year, but have been unable to do so. I can tell you that we rarely see anything in the news here about evacuations due to altitude sickness, with maybe a half dozen reports in a year. If any of my readers happen to find some reliable data on this, please comment and I will update this paragraph.

My thoughts – For starters I think it will be difficult to get any real accurate numbers for prevention or medications, because having any kind of control group is likely going to be impossible. In my previous career of Industrial Engineer, I became quite familiar with testing and analyzing data, my job was all about problem solving and numbers. When we found a problem, we would create a hypothesis as to the cause, and then design and preform tests to prove or disprove our theories. The same process is normally applied to medical testing and research, for example when there is a new drug, say for pain control, they would normally start with a group of people that have some sort of predictable pain, as they know that with no medication these people will be in a predictable amount of pain. The group is then divided into subgroups with some receiving the new medication, some receiving a proven medication, some receiving a placebo and maybe some that receive nothing. Based on the data they receive, usually over multiple tests, they can say that the new drug preformed better, or worse, than existing medication, nothing or a placebo.

This same process could also be applied to altitude, except for the fact that there is no guarantee that a return trip to high altitude, will produce the same effect as any previous trip, in any one individual. Because of this you never know how someone will react to altitude until they are actually here, and then once here, the experience is not likely to be replicated on following trips. So a person that visits and travels directly to Cusco, and then suffers from AMS, has no way of knowing if they would have been better if they started in the Sacred Valley. Likewise someone traveling to Cusco and starting in the Sacred Valley and not suffering any AMS effects, has no idea if they would also have not suffered AMS effects, had they gone straight to Cusco.

Despite these issues, it does seem as though acetazolamide (Diamox) {7} works well for prevention, as none of our past guests that have used it have suffered more than a mild headache. Other remedies like Coca tea, Muna tea, Herbal supplements like chlorophyll or other altitude mixes, and the common Soroche Pills that are widely available here, all seem to be hit or miss. Guests that have used these methods have reported a mix of results, from feeling much better to no help at all. Out of these alternative options the coca tea does seem to get the most favorable results from previous guests, but this could just be a placebo effect as there is no clinical evidence that coca tea is beneficial.

I also believe that reports on travel forums are not indicative of actual numbers, unfortunately people who suffer from AMS are much more likely to leave comments about their bad experience on travel forums, than those that do not suffer any ill effects, because of this the travel forums tend to contain almost nothing but bad reports of altitude effects, and if one would judge the risks solely by this, you would think that 90% or more of travelers are suffering severe AMS, which is defiantly not true.

My recommendations – If you are planning a visit to Cusco, here are some of my recommendations.

1 – Start Low: If you have time and are planning to visit multiple locations like Cusco, Puno and/or Arequipa, consider the altitude of each of these locations when planning. Starting your trip in Puno would not be wise, but visiting Arequipa, Cusco then Puno is.

2 – Take acetazolamide (Diamox): If you do not have the time to ascend slowly and will be traveling directly to Cusco, or maybe you are doing a trek and have to be at Cusco altitude before starting it, or feel the need to start in Cusco for any other reason. Taking acetazolamide is advisable, just remember to consult your physician or a travel doctor to make sure there will not be any issues for you.

3 – Start with Machu Picchu: While probably one of the easiest ways to reduce the risk or AMS, not everyone is a fan of this plan. Personally I do not like to move around a lot when traveling as it take me a few days to get used to a place and get any good sleep, and I would not want to see the best site first. For those of you that don’t mind moving around, are opposed to taking drugs, have had previous bad experiences with altitude, or for any other reason do not want to start in Cusco, then arriving and heading directly to the Sacred Valley, or even Machu Picchu for the first couple of nights, would be a good way to reduce your risk.

4 – Avoid, or greatly limit, alcohol for the first couple of days: Yes I know, for may of us a cold beer in the afternoon really hits the spot, but there are several reasons for this with the primary one being that alcohol may limit your bloods ability to absorb oxygen, additionally if you have too much, it can produce symptoms similar to AMS, maybe leading you to ignore them which could be bad. Additionally some side effects when taking acetazolamide {7} may be increased, so drinking alcohol while taking acetazolamide is not recommended.

5 – Limit activity the first couple of days: This does not mean that you have to sit on your but wasting time for the first few days, but do not plan any big hikes, treks, or any other strenuous activities for the first few days. Limit your exploration to short level walks and take extra breaks.

6 – Know the symptoms of AMS {1}: as I mentioned above, having a copy of the LLSS {4} can be helpful and allow you to actually track your symptoms, knowing the symptoms will tell you if you should stay at your current elevation a little longer, or let you know it is okay to ascend, which can be an important step in avoiding the more severe HAPE {5} and HACE {6}.

7 – Don’t be afraid to see a doctor: If you are scoring Severe AMS, or your symptoms are not improving or even getting worse, do not just tough it out. Ask your accommodation to recommend or call a doctor, or have some contact information ready just in case. If you have travel insurance the company may have a preferred provider, but if not, there are several tourist clinics in Cusco that are familiar with altitude and other travel issues, and may also have doctors on staff that speak your language. For reference here is a clinic that a past guest used and gave us good feed back on

In short I think that AMS is not something to be scared of, but it is something to be educated about, with a little preparation and information, you should be able to have a safe, enjoyable visit to Cusco, whether you start in the Sacred Valley or in Cusco itself.










About Lyle

I love travel and currently own and operate a Bed and Breakfast called GringoWasi with my beautiful Peruvian wife, the property is located in the small town of Huarocondo, and about 30 minutes West of Cusco Peru.
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2 Responses to AMS in Cusco

  1. Evangelina07 says:

    I was in Peru for a week and took the meds prescribed. They didn’t do a thing for me. I still got AMS and it was not fun.

    For me the only thing that helped was taking it easy and drinking lots and lots of water.

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