Altitude Sickness in Mexico City: Symptoms and How to Adjust
Mexico City is over a mile high. What the CDC says about altitude illness at this elevation, who should talk to a doctor first and how to ease the first few days.
Mexico City sits at 2,250 meters (7,382 feet), according to the US Centers for Disease Control and Prevention (CDC). Many new arrivals notice headache, breathlessness on stairs and poor sleep at first. Serious altitude illness is uncommon at this elevation, but people with heart or lung disease should get medical advice before moving.
How high is Mexico City compared with other high places?
Mexico City is just below the elevation where the CDC starts to count travelers as at risk of acute mountain sickness. The CDC Yellow Book chapter on high-altitude travel says anyone who is not acclimatized and sleeps at 2,450 meters or higher, “and sometimes lower,” is at risk.
| Place | Elevation (CDC figures) |
|---|---|
| Mexico City | 2,250 m (7,382 ft) |
| Vail, Colorado (lodgings) | 2,480 m (8,150 ft) |
| Cusco, Peru | about 3,350 m (11,000 ft) |
| La Paz, Bolivia | about 3,650 m (12,000 ft) |
The CDC’s Mexico chapter notes that healthy travelers from lower elevations, and people with heart and lung conditions, might need an acclimatization period in the capital.
What are the symptoms of altitude sickness?
Headache is the main symptom of acute mountain sickness, usually with at least one of these: loss of appetite, dizziness, fatigue, nausea or, less often, vomiting. The CDC compares it to a hangover. Symptoms usually start 2 to 12 hours after arrival, often during or after the first night, and generally clear within 12 to 48 hours if you do not go higher.
Symptoms that begin more than three days after arrival, with no further climb, should not be put down to altitude, the CDC says. A fever, chills or muscle aches point to an infection rather than altitude. At Mexico City’s elevation, many people notice only milder effects: breathlessness when walking uphill or climbing stairs, a faster heartbeat, dry eyes and lips, and lighter, broken sleep.
Who is more at risk?
Fitness does not protect you. The CDC says training and physical fitness do not change the risk, children are as susceptible as adults, and people over 50 have slightly less risk. How you reacted on earlier trips to similar heights is the best guide.
People with these conditions should see a doctor familiar with altitude before moving or traveling, even if the condition is well controlled:
- Coronary artery disease or heart failure.
- Chronic lung disease, including COPD, or low blood oxygen at sea level.
- Obstructive sleep apnea.
- Sickle cell disease or sickle cell trait.
- Pregnancy with complications.
Well-controlled asthma, controlled high blood pressure and diabetes appear in the CDC’s list of conditions with likely no extra risk. Mexico City’s air pollution adds a separate strain on the lungs, especially in the dry winter months; our guide to air quality and environmental contingencies explains the alerts.
How long does it take to adjust to Mexico City’s altitude?
The main acclimatization happens over the first three to five days, according to the CDC. Breathing deepens, blood oxygen improves and sleep gets better. Some adjustment continues for weeks to months, which is why runners and cyclists often find exercise harder for longer than a week.
The CDC’s checklist for high altitude includes advice that also helps in Mexico City:
- Avoid alcohol for the first 48 hours.
- Keep exercise mild for the first 48 hours.
- If you drink coffee every day, keep drinking it, so a withdrawal headache does not get confused with altitude.
- Do not take sleeping pills or other drugs that depress breathing without medical advice.
Drink water regularly, since the CDC lists dehydration among the conditions that can be mistaken for altitude illness, and use sunscreen: ultraviolet radiation is stronger at high altitude.
When should you see a doctor?
See a doctor if a headache gets worse despite rest and ordinary pain relievers, or if you are short of breath while resting, have a cough with chest tightness, are confused or walk unsteadily. The CDC lists breathlessness at rest and loss of coordination as warning signs of high-altitude pulmonary and cerebral edema. Both are rare at Mexico City’s elevation, but they are emergencies: call 911. Our page on emergency numbers in Mexico City lists other lines to save.
Some people take acetazolamide to speed adjustment before trips to much higher places. It needs a prescription in Mexico; our guide to pharmacies and prescriptions explains the rules. This page summarizes CDC guidance and is not medical advice; a doctor should assess your own risk.
Does altitude matter for day trips from Mexico City?
It can. Volcanoes and national parks near the capital, such as Nevado de Toluca and Iztaccíhuatl, reach far higher than the city. The CDC advises against going from low altitude to a sleeping altitude above 2,750 meters in one day, and says most risk comes from where you sleep. A few days in the city first helps; an overnight stay high on a mountain is a bigger step than a day visit.
Bottom line
Plan an easy first two or three days after arriving: light activity, no alcohol, regular water and early nights. If you have heart or lung disease, sleep apnea or sickle cell trait, talk to your doctor before the move, and bring enough of your usual medicines with a Spanish-translated prescription.
FAQ
Is Mexico City high enough to cause altitude sickness?
It can, mostly in mild form. Mexico City is at 2,250 meters, just below the 2,450-meter level the CDC uses for clear risk, and the CDC says illness sometimes occurs lower. Most people adjust within a few days.
Does altitude sickness affect children?
Yes. The CDC says children are as susceptible as adults. Young children may show it as loss of appetite, irritability and pale skin rather than complaining of a headache.
Why do I sleep badly in Mexico City?
Lighter, broken sleep is common in the first nights at altitude because blood oxygen is lowest during sleep. It usually improves as you acclimatize; avoid alcohol and sedatives as sleep aids.
Should I take medicine to prevent altitude sickness before flying to Mexico City?
Usually not. The CDC puts a first night below 2,750 meters in its low-risk group, for which preventive medicine is not indicated. Ask your doctor, especially if you had altitude illness before or plan to go much higher soon after arriving.