Free safety tool
Altitude sickness self-check
Rate four symptoms using the Lake Louise score to gauge whether you might have acute mountain sickness - and see exactly what to do next. Educational only, never a substitute for descending or getting help.
This is an educational self-check based on the Lake Louise AMS score - not a medical diagnosis. When in doubt, stop ascending and descend. If anyone shows severe symptoms, treat it as an emergency.
TrekGuard runs this exact self-check offline at altitude, reminds you to re-check as you climb, and pairs it with your live altitude and SOS tools - so you catch AMS early when it matters.
Get TrekGuard freeHow the Lake Louise score works
The Lake Louise Acute Mountain Sickness score is the standard self-report tool used in altitude research and by rescue posts in Nepal. The 2018 revision rates four symptoms from 0 to 3: headache, gastrointestinal upset (appetite loss, nausea or vomiting), fatigue or weakness, and dizziness or light-headedness. The older sleep item was dropped because poor sleep at altitude is common in people who are otherwise well.
A score counts as AMS only when headache is present and the total is 3 or more. Totals of 3 to 5 are mild, 6 to 9 moderate, and 10 to 12 severe. Symptoms without a headache do not meet the definition, but they are not a green light either: recheck in a few hours and treat any new headache as AMS.
What each result means
- Mild: do not go higher. Rest at the same altitude, drink, treat the headache, and recheck in six hours and again before sleeping. Most mild AMS settles within a day or two if you stop ascending.
- Moderate or severe: descend now, with company, and keep going down until symptoms clearly improve. Do not wait for morning.
- Emergency signs: confusion, drowsiness, or losing balance when walking heel to toe suggest high-altitude cerebral edema. Breathlessness at rest, a wet cough or blue lips suggest high-altitude pulmonary edema. Either overrides the score entirely: descend immediately and get help.
Using it on the trail
Score yourself every evening above 2,500 m, and again in the morning if anything scored, because a score that is rising through the day means something different from a single reading. Compare it against your schedule in the acclimatization planner, read the fuller guide to the Lake Louise score and the notes on preventing altitude sickness, and keep the safety guide available offline. This tool is educational and is not a diagnosis; a clinician, a rescue post or descent always comes first.