How to Prevent Altitude Sickness Before You Go

A headache after landing in the Andes can be unsettling, especially when you are far from your usual doctor. The good news is that most cases are preventable. To prevent altitude sickness, plan for a slower ascent, recognize early symptoms, and avoid pushing through discomfort simply because your itinerary is full.

For travelers and digital nomads, the challenge is often practical: a late flight, an early mountain tour, a celebratory drink, poor sleep, and a desire to make the most of a short stay. At altitude, those small decisions can add up. A thoughtful first 24 to 48 hours gives your body time to adapt and helps you tell the difference between normal travel fatigue and a problem that needs care.

What altitude sickness is and when it happens

Altitude sickness, also called acute mountain sickness or AMS, occurs when the body has not yet adjusted to lower oxygen levels at higher elevations. It is most common after rapid ascent above about 8,000 feet, or 2,500 meters, though individual sensitivity varies widely. Being young, fit, and experienced in the outdoors does not guarantee protection.

Symptoms often begin within six to 24 hours of arriving at a higher elevation. A mild headache is the classic first sign, usually paired with one or more of the following: nausea, reduced appetite, dizziness, unusual fatigue, poor sleep, or a general flu-like feeling.

Medellín sits at roughly 4,900 feet, or 1,500 meters. Most visitors do not develop true altitude sickness there, even if they arrive from sea level. Still, the city’s elevation, warm days, travel fatigue, dehydration, and alcohol can leave some people feeling off during their first day or two. The greater concern is usually a rapid onward trip to significantly higher destinations, such as mountain hikes, high-altitude cities, or remote areas of the Andes.

How to prevent altitude sickness before and during ascent

The most reliable strategy is gradual ascent. If your plans take you above 8,000 feet, spend a night at an intermediate elevation when possible. Once you are above 10,000 feet, a commonly used rule is to increase your sleeping elevation by no more than about 1,000 to 1,600 feet per night, with a rest day every few days. This is not always realistic on a short trip, but even one extra acclimatization day can make a meaningful difference.

Your daytime route can be higher than where you sleep. In fact, hiking or traveling higher during the day and returning to a lower sleeping elevation is often useful for acclimatization. The key is not to keep gaining sleeping altitude quickly when symptoms have started.

Arrive with a lighter first-day plan. Choose a walk around your neighborhood instead of a demanding hike, eat regular meals, and make sleep a priority. If you have just flown in, your body is already adapting to disrupted sleep, dry cabin air, time changes, and a different routine. Treat the first day as part of the trip, not wasted time.

Hydration helps, but it is not a cure for altitude illness. Drink consistently enough that you are not thirsty and your urine is pale yellow. Avoid forcing large amounts of water, which can make you feel worse and, in rare cases, create its own medical risks. Eat normally, favoring familiar meals with carbohydrates and adequate salt rather than skipping food because you feel mildly nauseated.

Alcohol and sedating medications deserve extra caution during the first day or two at a new elevation. Both can worsen sleep quality and breathing overnight, while also masking developing symptoms. One drink may be fine for some people at moderate elevations, but if you are heading higher the next morning or already have a headache, it is sensible to skip it.

Do fitness and supplements help?

Good fitness improves your ability to enjoy an active trip, but it does not prevent AMS. A marathon runner can become sick after a fast ascent, while a less athletic traveler may acclimatize without difficulty. Your personal history matters more: if you have had altitude sickness before at a similar elevation and rate of ascent, your risk is higher on a comparable trip.

You may hear that coca tea, garlic, electrolyte packets, or various supplements prevent altitude sickness. Some can be comforting, and electrolytes can be useful after sweating, vomiting, or diarrhea. But none replaces gradual ascent, and evidence for most supplements is limited. Do not rely on a tea or powder as permission to ascend faster than your body can handle.

When preventive medication makes sense

For people with a history of AMS or an itinerary that requires rapid ascent, a clinician may recommend acetazolamide. This prescription medication supports acclimatization by changing the way your body regulates breathing and acid-base balance. It is typically started before ascent or on the day of ascent, depending on the plan.

Acetazolamide is not necessary for every traveler, and it is not right for everyone. A medical professional should review your allergy history, kidney concerns, pregnancy status, current medications, and trip details before prescribing it. Common side effects can include tingling in the fingers or toes, more frequent urination, and altered taste, especially for carbonated drinks.

Dexamethasone may be used in select situations, but it is not a casual substitute for acclimatization. It can suppress symptoms without allowing the same degree of natural adaptation, so it should be used only under clear medical guidance. If you are planning a high-altitude trek on a fixed schedule, arrange a pre-travel consultation rather than making medication decisions after symptoms appear.

Do not ignore symptoms that are getting worse

Mild symptoms call for a pause, not a test of willpower. Do not go higher until you feel better. Rest, hydrate normally, avoid alcohol, eat what you can tolerate, and reassess. If a headache is mild and isolated, it may be related to travel, dehydration, caffeine withdrawal, or tension. But a headache combined with nausea, dizziness, fatigue, or poor coordination after ascent should be treated as possible AMS.

The most effective treatment for worsening altitude sickness is descent. Going down, even by a relatively modest amount, can improve symptoms quickly. Supplemental oxygen and certain medications may also be appropriate, but neither should delay descent when serious symptoms are present.

Seek urgent medical help immediately if you develop shortness of breath while resting, chest tightness, a persistent cough, confusion, severe weakness, fainting, difficulty walking in a straight line, blue or gray lips, or a severe headache that does not improve. These may signal high-altitude pulmonary edema or high-altitude cerebral edema, which are medical emergencies.

It is also wise to seek care if vomiting prevents you from drinking fluids, symptoms are not improving after rest, or you are unsure whether your symptoms are altitude-related. Travelers sometimes assume every headache at elevation is AMS, when infection, migraine, dehydration, medication effects, or another condition may be involved.

A practical plan for travelers in Medellín

If Medellín is your only destination, give yourself a calm arrival day, stay hydrated, eat regularly, and do not panic over mild fatigue or a light headache. The city’s elevation is moderate, and most healthy visitors adjust comfortably. If you feel unwell, avoid self-diagnosing after a long flight, especially if fever, respiratory symptoms, significant vomiting, or severe pain are part of the picture.

If Medellín is the first stop before a higher-altitude itinerary, use your time here strategically. Recover from travel, confirm your route and sleeping elevations, and speak with a clinician before leaving if you have prior altitude problems or a tight ascent schedule. Equilibrium Urgent Care can provide English-speaking medical guidance for visitors who want a clear plan before traveling farther into the mountains.

A well-paced itinerary may not look as ambitious on paper, but it usually feels far better in real life. Give your body time to catch up, and you will have more energy for the views, the work, and the experiences that brought you there.