Mountain sickness: quick, practical guide

Feeling dizzy, having a pounding headache or breathless after going up a mountain? That could be mountain sickness (also called altitude sickness). It can start at moderate heights—around 2,400 m (8,000 ft)—and get serious fast if you ignore it. Here's what to watch for and what to do that actually helps.

Symptoms and when to act

Early signs are headache, nausea, poor sleep, fatigue, dizziness, and reduced appetite. If the headache is strong and won't go away with painkillers, or you feel confused, unsteady, or very short of breath at rest, treat it as an emergency.

There are three main forms:

• Acute Mountain Sickness (AMS): headache plus fatigue, nausea, or trouble sleeping.
• High-Altitude Cerebral Edema (HACE): severe confusion, loss of coordination, and behavior changes. This is life-threatening.
• High-Altitude Pulmonary Edema (HAPE): persistent cough, breathlessness at rest, and a feeling of choking. Also life-threatening.

If you suspect HACE or HAPE, descend immediately and get medical help. Oxygen and evacuation save lives.

Prevention and simple treatments

Plan your ascent. Gain no more than 300–500 m (1,000–1,600 ft) of sleeping elevation per day once above 3,000 m. Follow the "climb high, sleep low" rule: hike higher during the day but sleep lower. Build an extra rest day every 600–900 m of gain.

Hydrate and eat regular, easy-to-digest meals. Avoid alcohol and heavy exertion during the first 24–48 hours at a new altitude. If you’ve had altitude problems before, take extra care—past AMS raises your risk.

Medications people commonly use:

• Acetazolamide (Diamox) can help you acclimatize. Talk to a doctor about dosing and side effects before your trip.
• Ibuprofen or paracetamol can ease headache but don’t treat the cause—descent does.
• Dexamethasone is used in severe cases (HACE) to reduce brain swelling; it’s a short-term emergency drug and needs medical oversight.
• Oxygen and drugs like nifedipine are used for HAPE along with descent and medical care.

If symptoms are mild, stop going higher and rest. If symptoms improve within 24 hours, you might continue slowly. If they worsen or include confusion or breathlessness, descend at least 500–1,000 m and seek help.

Packing tips: bring a pulse oximeter (useful but not definitive), a basic first-aid kit, acetazolamide if your doctor prescribes it, and a plan for evacuation. Know the nearest clinic and transport options.

Quick checklist before you go: plan gradual ascent, tell someone your route, pack layers and emergency gear, avoid alcohol, and consult a doctor if you have lung or heart disease. Mountain sickness is common but manageable when you recognize it early and act fast.