Altitude sickness prevention

Overview

Altitude sickness is a set of symptoms that can happen when you go to a high altitude too quickly, without giving your body time to adjust to the lower oxygen levels. It is also called acute mountain sickness (AMS).

Altitude sickness is very common among people who travel to high mountains for hiking, skiing, or climbing. Over half of people who go above 3,500 meters may get mild symptoms.

It can affect anyone, even very fit people. Your risk depends on how fast you climb, how high you go, and your personal body response.

Symptoms

Common symptoms

• Headache
• Nausea or vomiting
• Dizziness or lightheadedness
• Fatigue and weakness
• Loss of appetite
• Trouble sleeping

Symptoms in children

• Fussiness or crying more than usual
• Refusing to eat or drink
• Complaining of headache or stomachache
• Acting very tired or sleepy

Symptoms in older adults

• Same symptoms as adults, but may be mistaken for other health conditions
• Increased confusion or feeling unsteady
• Worsening of existing heart or lung problems

Causes

Main causes

• Rapid ascent to high altitude without giving the body time to adapt (acclimatize)
• Lower oxygen levels at high altitudes cause blood vessels in the brain and lungs to leak fluid

Risk factors

• Climbing too fast (gaining more than 300–500 meters per day above 2,500 meters)
• Previous history of altitude sickness
• Living at or near sea level before traveling to high altitude
• Dehydration
• Overexertion (exercising too hard)
• Drinking alcohol or taking sleeping pills at high altitude

When to see a doctor

See a doctor urgently if:

• Any symptoms that get worse despite resting and drinking water
• Signs of HACE (confusion, loss of coordination) or HAPE (breathing trouble, cough)

Book a routine appointment if:

• If you plan to travel above 3,500 meters and have a heart or lung condition, talk to your doctor before you go
• If you have had altitude sickness before and want advice on prevention

Diagnosis

Doctors diagnose altitude sickness based on your symptoms and your recent travel history (how fast you went up and how high). There is no single test.

Tests that may be done

• Pulse oximetry (a small clip on your finger to measure oxygen in your blood)
• Listening to your lungs with a stethoscope
• In severe cases, a chest X-ray or CT scan of the brain

What to expect at your appointment

Your doctor will ask about your climb, your symptoms, and your medical history. They may check your oxygen level. If symptoms are serious, they may recommend going to a lower altitude right away.

Treatment

The main treatment for altitude sickness is going down to a lower altitude (descending) as soon as possible. Rest and extra oxygen also help. For mild symptoms, you may recover just by stopping your climb and waiting.

Self-care at home

• Stop climbing and rest at the same altitude until symptoms improve
• Drink plenty of water — dehydration makes symptoms worse
• Avoid alcohol and tobacco
• Use over-the-counter pain relief for headache, but only if you are sure you don't have severe altitude sickness

Medical treatments

Doctors may prescribe medications that help the body adjust to altitude or reduce swelling in the brain or lungs. Oxygen therapy is often used if available. For severe forms, descent and medical emergency care are essential. Always follow your doctor's advice.

When is surgery considered?

Surgery is not used to treat altitude sickness.

Living with this condition

If you have had mild altitude sickness, you can usually return to normal activities once you descend. Most people recover fully in a day or two.

Lifestyle tips

• When traveling to high altitudes, plan a slow ascent with rest days
• Keep yourself well hydrated
• Avoid overexertion the first few days
• Consider using portable oxygen if available

Diet and exercise

Eat a light, high-carbohydrate diet at altitude. Avoid heavy meals. Exercise should be gentle at first — let your body adjust before doing strenuous hikes.

Mental health and emotional wellbeing

Mild symptoms can be scary, but knowing what to expect can help reduce anxiety. If you feel very anxious or panicked, tell your travel partner or guide. Severe altitude sickness can affect thinking and mood.

Prevention

Yes, altitude sickness can often be prevented by going up slowly, staying hydrated, and giving your body time to acclimate. For some people, medication taken before and during the climb can help — ask your doctor about it.

Screening programmes

There is no routine screening test. Talk to your doctor if you have a medical condition and plan to travel to high altitude.

Complications

If left untreated

• High-altitude cerebral edema (HACE) — swelling in the brain, which can cause confusion, coma, and death
• High-altitude pulmonary edema (HAPE) — fluid in the lungs, which can cause severe breathing problems and death

Long-term outlook

The outlook is excellent if you recognize symptoms early and descend. Most people recover completely with no lasting effects. Severe cases can be life-threatening, but quick action saves lives.

Find support

Local organisations

• NHS (UK) · UK

External links open third-party websites. Ruqelo Health is not responsible for external content. Listing an organisation does not imply endorsement.