Condition
High-Altitude Performance
High altitude means less available oxygen, which stresses the body above about 2500 metres until it adapts with more red blood cells, faster breathing and higher cardiac output. Iron and beetroot juice nitrates have the best evidence, rated strong and moderate respectively, and a small trial in low-oxygen air found caffeine improved muscular endurance. That caffeine study had only eight people, so it is a hint rather than a firm answer.
Sources: PMID 27600147; PMID 39519456
- Supplements studied
- 2
- Graded outcomes
- 1
- Trials
- 2
- People studied
- 23
Evidence by supplement
- Strong
- Moderate
- Limited
- Very limited
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Muscular Endurance Small Improvement | Improves (the measure goes up) | Small effect | 1 study | 8 people | ||
Studies that measured muscular endurance | ||||||
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Exercise Performance During Hypoxia | Improves (the measure goes up) | 2 studies | 15 people | |||
Studies that measured exercise performance during hypoxia | ||||||
Key findings
- Muscular EnduranceImproves (the measure goes up)
The High Altitude Performance & Acclimatization protocol
2 primary supplements · 7 supporting supplements
- IronIf deficient: 18–65 mg elemental iron daily; start before altitude exposure
- Beetroot Juice / Nitrates400–600 mg nitrate (70–140 ml concentrated beetroot juice) 2–3 hours before activity
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Studies cited
3 studies from PubMed
- Dietary nitrate improves muscle but not cerebral oxygenation status during exercise in hypoxia
- Dietary nitrate reduces muscle metabolic perturbation and improves exercise tolerance in hypoxia
- The Effect of Pre-Exercise Caffeine and Glucose Ingestion on Endurance Capacity in Hypoxia: A Double-Blind Crossover Trial.