Category: Health & Safety | Reading time: 7 min
Altitude sickness is the topic that comes up in every pre-trek conversation and the one most people secretly hope does not apply to them. It applies to everyone. Not necessarily in a serious way, not necessarily in a way that will affect your trek, but the physiology of reduced oxygen at high altitude does not make exceptions for fitness levels, age, experience, or optimism.
The good news is that altitude sickness on the Salkantay is almost always manageable with the right preparation. The people who have genuinely bad experiences are almost always the ones who ignored the acclimatization advice, rushed to altitude too quickly, or failed to recognize early symptoms before they became serious ones. This article covers what you actually need to know, without the alarmism and without the false reassurance.
When you ascend to high altitude, the air pressure decreases and with it the amount of oxygen available in each breath. Your body responds by breathing faster and working harder to deliver oxygen to your organs and muscles. This adjustment takes time. When you ascend faster than your body can adapt, the result is Acute Mountain Sickness, known as AMS.
Cusco sits at 3,400 meters. The first Salkantay campsite at Soraypampa sits at 3,900 meters. The Salkantay Pass sits at 4,630 meters. You will be spending time at all three of these altitudes within the first two days of the trek. That progression is manageable with proper preparation and becomes genuinely difficult without it.
AMS is not the only altitude-related condition worth knowing about, but it is by far the most common on the Salkantay. The two more serious conditions, High Altitude Pulmonary Edema and High Altitude Cerebral Edema, are rare but require immediate descent and medical attention if they occur. Understanding the difference between mild AMS and these more serious conditions is important.
Mild AMS presents as a headache, usually described as a dull pressure rather than a sharp pain, combined with one or more of the following: fatigue beyond what the day’s walking would normally cause, nausea with or without vomiting, dizziness when standing or changing position, difficulty sleeping, and a general feeling of heaviness and reduced motivation. Mild AMS is common in the first day or two in Cusco and does not automatically mean your trek is in jeopardy. It means your body is adapting and needs time.
Moderate AMS involves the same symptoms but more pronounced, with the headache becoming more persistent and less responsive to standard pain relief, increasing nausea, and a noticeable reduction in coordination or balance. At this level, ascending further is not advisable until symptoms improve.
Severe AMS, HACE, and HAPE are the conditions that require immediate descent. Symptoms that indicate a serious problem include loss of coordination that makes walking in a straight line difficult, confusion or unusual behavior, a persistent cough producing pink or frothy mucus, severe breathlessness at rest, and an inability to keep fluids down. Any of these symptoms in a trekking group are a medical emergency. Every guide at Salkantay Horizons is trained to recognize and respond to them.
Acclimatization is the only reliable prevention for altitude sickness. Everything else on this list, the medication, the coca tea, the hydration, is supportive. Time at altitude is the mechanism.
Arrive in Cusco at least two full nights before your trek begins. Not one night. Not the night before. Two nights minimum, three if your schedule allows. Spend those days moving at a reduced pace, making short walks rather than long days of sightseeing, and paying attention to how your body is responding. If you arrive in Cusco feeling fine on Day 1 and wake up on Day 2 with a mild headache and low energy, that is normal and it does not mean you are going to have a bad trek. It means the acclimatization process is working.
The worst thing you can do is fly into Cusco from sea level and attempt the Salkantay the following morning. People do it. It rarely ends well.
Hydration Drink significantly more water than you normally would from the moment you arrive in Cusco. Dehydration and AMS share many symptoms and compound each other. A useful benchmark is that your urine should be pale yellow throughout your time at altitude. Dark urine at altitude is a warning sign worth taking seriously.
Food and alcohol Eat light meals in the first 24 hours in Cusco, particularly on arrival day. Your digestive system slows at altitude and heavy food adds discomfort to discomfort. Avoid alcohol for the first two nights. Alcohol dehydrates you, disrupts sleep, and impairs the physiological adaptation process in ways that are measurable and genuinely significant at altitude. One beer on the night before the trek is a different situation from two bottles of wine on your first night in Cusco.
Sleep Your body does the majority of its acclimatization work during sleep. Disrupted or shortened sleep at altitude sets back the process. Go to bed at a reasonable hour during your acclimatization days, even if the energy of Cusco makes that feel counterintuitive.
Pace on the trail The Quechua phrase poco a poco, little by little, exists for a reason in this part of the world. On Day 1 and the ascent on Day 2, walk at a pace where you can hold a conversation without significant effort. Your guide will set a pace appropriate for the group. If you feel the urge to push ahead, resist it. The pass will still be there whether you arrive at a sprint or a steady walk, and the difference in how you feel when you get there will be significant.
Coca leaf tea has been used by Andean communities for centuries as an aid for altitude symptoms and it remains the most widely consumed remedy in Cusco. It is legal in Peru, available at virtually every restaurant and hotel, and mildly effective at reducing the symptoms of mild AMS, particularly headache and nausea.
It works partly through mild stimulant properties that improve circulation and partly through a direct effect on the gastric system that reduces nausea. The active alkaloid content in the tea is low enough that it does not produce any significant stimulant effect beyond what you might expect from a moderate cup of coffee.
Drink it regularly during your acclimatization days in Cusco and it will help. Do not treat it as a substitute for proper acclimatization time. It is an aid, not a solution.
Coca leaves can also be chewed directly, which is the traditional method and slightly more effective than the tea. A small wad of leaves held against the inside of the cheek releases the active compounds gradually over 20 to 30 minutes. Many guides carry coca leaves on the trail and offer them to trekkers on the Day 2 ascent.
Diamox, the brand name for acetazolamide, is a prescription medication that accelerates acclimatization by stimulating faster breathing, which increases blood oxygen levels. It is widely used by high-altitude trekkers and genuinely effective at reducing the incidence and severity of AMS.
If you are considering Diamox, consult your doctor before traveling. It is not suitable for everyone, particularly people with sulfa drug allergies, and it has side effects including increased urination and mild tingling in the hands and feet. The standard protocol is to begin taking it 24 hours before ascending to significant altitude.
Diamox does not eliminate the need for acclimatization time. It reduces the risk of AMS and makes the adaptation process smoother, but people who take it and still rush to altitude without adequate acclimatization can still develop symptoms.
Mild symptoms: Tell your guide. This is the most important thing. Guides at Salkantay Horizons are trained in altitude medicine and will assess your symptoms, adjust the group pace if needed, and monitor your condition through the day. Mild AMS symptoms often improve with rest, hydration, and time. Do not attempt to push through moderate or severe symptoms without speaking to your guide first.
If symptoms worsen: The treatment for worsening altitude sickness is descent. There are no exceptions to this rule. A descent of even 300 to 500 meters can produce rapid improvement in symptoms. Your guide carries emergency oxygen on all departures above 4,000 meters, which can provide temporary relief while descent is organized. Emergency evacuation protocols are in place for all our departures.
Do not ascend if you have moderate or severe symptoms. The Salkantay Pass will be there next time. The decision to descend rather than push through serious symptoms is always the right one and always reversible. The decision to ignore serious symptoms and continue ascending is sometimes neither.
Some people acclimatize quickly and feel minimal effects even at 4,630 meters. Others with equivalent fitness and experience struggle on the same mountain on the same day. There is a genuine genetic component to altitude tolerance that no amount of training or preparation eliminates. This is not a reason to be anxious. It is a reason to take the acclimatization advice seriously regardless of how fit you are or how well you did at altitude on a previous trip. Previous altitude experience does not guarantee the same response next time.
All Salkantay Horizons guides carry a satellite communication device on routes above 4,000 meters. Emergency oxygen is standard equipment on every departure. Our operations team in Cusco maintains 24/7 contact with all active trek groups and evacuation protocols are tested and in place. You will be given a full safety briefing before departure that covers altitude sickness recognition, our emergency procedures, and the contact information for our Cusco office.
If you have specific health concerns about altitude or questions about medication, we are happy to advise based on the time of year and the specific route you are considering. Get in touch before you book.
