Altitude Adaptation
Better performance and acclimatization at high elevations.
TL;DR
Altitude adaptation is driven by ascent rate and time at elevation. Acetazolamide and iron sufficiency have the strongest evidence; most marketed "altitude" supplements do not prevent acute mountain sickness.
Why It Matters
Above roughly 2,500 m, falling arterial oxygen triggers ventilatory acclimatization and, over days to weeks, erythropoietin-driven red cell mass expansion. Acute mountain sickness affects 25-50% of unacclimatized travellers at 3,500 m. Iron availability is rate-limiting for the haemoglobin response, so low ferritin blunts adaptation. HAPE and HACE are medical emergencies whose only reliable treatment is descent.
How to Measure
Track resting SpO2 and morning heart rate daily at altitude, and score symptoms with the Lake Louise questionnaire. Before travel, check ferritin, transferrin saturation and haemoglobin. A falling SpO2 with worsening breathlessness at rest, ataxia or confusion means descend immediately.
Biomarkers
Optimization Protocol
1. Plan the ascent profile first: above 3,000 m, raise sleeping elevation 300-500 m/night with a rest day every 3-4 days. 2. Repair iron status 8-12 weeks out if ferritin is low. 3. Discuss acetazolamide 125 mg twice daily starting the day before ascent with a clinician for rapid ascents or prior AMS. 4. Hydrate to thirst and avoid alcohol on the first two nights. 5. Reduce training intensity for the first 3-5 days. 6. Never ascend further with active AMS symptoms.
Lifestyle Levers
- •Graded ascent profile
- •Rest days
- •Avoid alcohol on arrival
- •Adequate carbohydrate intake
- •Reduce early exercise intensity
- •Sleep low, climb high
Supporting Supplements
Cordyceps
Traditional use at altitude is long-standing, but controlled human trials do not show improved acclimatization or fewer AMS symptoms.
Iron
Iron sufficiency is required for the haemoglobin response to hypoxia, so correcting low ferritin measurably supports acclimatization.
Supporting Research
Frequently Asked Questions
Typical Timeframe
Ventilatory adaptation begins within 24-48 hours; haemoglobin and red cell mass gains take 2-4 weeks at elevation.
Research Summary
My Notes
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This information is for educational purposes only. Always consult a healthcare professional before starting any supplement regimen.