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
83 studies from PubMed
- Dietary nitrate improves muscle but not cerebral oxygenation status during exercise in hypoxia
- Effects of 1,3-dimethylamylamine and caffeine alone or in combination on heart rate and blood pressure in healthy men and women
- Ergogenic effect of varied doses of coffee-caffeine on maximal aerobic power of young African subjects
- The effect of caffeine ingestion on mood state and bench press performance to failure
- Effect of Caffeine on LT, VT and HRVT
- Metabolic effects of caffeine ingestion and physical work in 75-year old citizens. A randomized, double-blind, placebo-controlled, cross-over study
- Dose response effects of a caffeine-containing energy drink on muscle performance: a repeated measures design
- Acute caffeine ingestion increases voluntarily chosen resistance training load following limited sleep
- Effects of caffeine on the metabolic and catecholamine responses to exercise in 5 and 28 degrees C
- Caffeine ingestion reverses the circadian rhythm effects on neuromuscular performance in highly resistance-trained men
- Effect of two doses of caffeine on muscular function during isokinetic exercise
- Dose effect of caffeine on testosterone and cortisol responses to resistance exercise
- The effects of low-dose caffeine on perceived pain during a grip to exhaustion task
- Caffeine increases sweating sensitivity via changes in sudomotor activity during physical loading
- Effects of caffeinated and decaffeinated coffee on biological risk factors for type 2 diabetes: a randomized controlled trial
- Caffeine and sprinting performance: dose responses and efficacy
- Effects of caffeine on prolonged intermittent-sprint ability in team-sport athletes
- Caffeinated chewing gum increases repeated sprint performance and augments increases in testosterone in competitive cyclists
- The effects of different doses of caffeine on endurance cycling time trial performance
- Effect of caffeine ingestion on time trial performance in cyclists: a systematic review and meta-analysis.
- Effect of ambient temperature on caffeine ergogenicity during endurance exercise
- The influence of a CYP1A2 polymorphism on the ergogenic effects of caffeine
- Caffeine ingestion, affect and perceived exertion during prolonged cycling
- Effect of caffeine intake on pain perception during high-intensity exercise
- Caffeine as an analgesic adjuvant for acute pain in adults
- Caffeine for the prevention of injuries and errors in shift workers.
- Caffeine enhances working memory for extraverts
- Comparing the benefits of caffeine, naps and placebo on verbal, motor and perceptual memory
- Subjective, behavioral, and physiological effects of acute caffeine in light, nondependent caffeine users
- Effects of caffeine and glucose, alone and combined, on cognitive performance
- Effects of acute caffeine consumption following sleep loss on cognitive, physical, occupational and driving performance: A systematic review and meta-analysis.
- Effect of caffeine on reactive agility time when fresh and fatigued
- Effects of Nutritional Interventions on Accuracy and Reaction Time with Relevance to Mental Fatigue in Sporting, Military, and Aerospace Populations: A Systematic Review and Meta-Analysis.
- Effect of caffeine on target detection and rifle marksmanship
- Association of the anxiogenic and alerting effects of caffeine with ADORA2A and ADORA1 polymorphisms and habitual level of caffeine consumption
- Caffeine: a double-blind, placebo-controlled study of its thermogenic, metabolic, and cardiovascular effects in healthy volunteers
- Caffeine can decrease insulin sensitivity in humans
- Effects of caffeine on glucose tolerance: a placebo-controlled study
- Caffeine ingestion decreases glucose disposal during a hyperinsulinemic-euglycemic clamp in sedentary humans
- Caffeinated coffee does not acutely affect energy intake, appetite, or inflammation but prevents serum cortisol concentrations from falling in healthy men
- Influence of caffeine on perception of effort, metabolism and exercise performance following a high-fat meal
- Impact of acute caffeine ingestion on endothelial function in subjects with and without coronary artery disease
- Caffeine and opening the eyes have additive effects on resting arousal measures
- Effects of diurnal variation and caffeine consumption on Test of Variables of Attention (TOVA) performance in healthy young adults
- Caffeine supplementation and multiple sprint running performance
- Effects of caffeine on repeated sprint ability, reactive agility time, sleep and next day performance
- Genetic determinants of blood pressure responses to caffeine drinking
- Caffeine and Physiological Responses to Submaximal Exercise: A Meta-Analysis
- Wake up and smell the coffee: caffeine supplementation and exercise performance-an umbrella review of 21 published meta-analyses
- Effects of acute ingestion of caffeine on team sports performance: a systematic review and meta-analysis.
- Caffeine for asthma.
- The Effect of Consuming Caffeine Before Late Afternoon/Evening Training or Competition on Sleep: A Systematic Review with Meta-Analysis.
- The effect of caffeine on subsequent sleep: A systematic review and meta-analysis.
- The Prophylactic Effect of Acetaminophen and Caffeine on Post Dural Puncture Headache after Spinal Anesthesia for Cesarean Section: A Randomized Double-Blind Clinical Trial.
- The Effect of Pre-Exercise Caffeine and Glucose Ingestion on Endurance Capacity in Hypoxia: A Double-Blind Crossover Trial.
- Dietary nitrate reduces muscle metabolic perturbation and improves exercise tolerance in hypoxia
- Dietary nitrate supplementation reduces the O2 cost of walking and running: a placebo-controlled study
- Dietary nitrate supplementation improves team sport-specific intense intermittent exercise performance
- Influence of dietary nitrate supplementation on human skeletal muscle metabolism and force production during maximum voluntary contractions
- Effect of beetroot juice on lowering blood pressure in free-living, disease-free adults: a randomized, placebo-controlled trial
- Absence of an effect of high nitrate intake from beetroot juice on blood pressure in treated hypertensive individuals: a randomized controlled trial
- Effect of inorganic nitrate supplementation on blood pressure in older adults: A systematic review and meta-analysis
- Effects of short-term dietary nitrate supplementation on blood pressure, O2 uptake kinetics, and muscle and cognitive function in older adults
- Nitrate Derived From Beetroot Juice Lowers Blood Pressure in Patients With Arterial Hypertension: A Systematic Review and Meta-Analysis.
- Whole beetroot consumption acutely improves running performance
- The effects of dietary nitrate supplementation on endurance exercise performance and cardiorespiratory measures in healthy adults: a systematic review and meta-analysis.
- The Effect of Dietary Nitrate Supplementation on Endurance Exercise Performance in Healthy Adults: A Systematic Review and Meta-Analysis.
- Nitrate supplementation improves physical performance specifically in non-athletes during prolonged open-ended tests: a systematic review and meta-analysis.
- Factors that Moderate the Effect of Nitrate Ingestion on Exercise Performance in Adults: A Systematic Review with Meta-Analyses and Meta-Regressions.
- The Effect of Dietary Nitrate on the Contractile Properties of Human Skeletal Muscle: A Systematic Review and Meta-Analysis.
- Effect of dietary nitrate on blood pressure, endothelial function, and insulin sensitivity in type 2 diabetes
- Pharmacokinetic study of amaranth extract in healthy humans: A randomized trial
- Plasma nitrate, dietary nitrate, blood pressure, and vascular health biomarkers: a GRADE-Assessed systematic review and dose-response meta-analysis of randomized controlled trials.
- Regulatory effect of dietary nitrate on blood pressure: a meta-analysis of randomized controlled trials.
- Effect of dietary nitrate on human muscle power: a systematic review and individual participant data meta-analysis.
- Does Nitrate Supplementation Improve Muscle Strength, Power, and Sprint Performance in Females? A Systematic Review and Meta-Analysis.
- Effects of Dietary Nitrate Supplementation on Back Squat and Bench Press Performance: A Systematic Review and Meta-Analysis.
- The Effect of Dietary Nitrate Supplementation on Isokinetic Torque in Adults: A Systematic Review and Meta-Analysis.
- Dietary nitrate supplementation to enhance exercise capacity in patients with COPD: Evidence from a meta-analysis of randomized controlled trials and a network pharmacological analysis.
- Evaluating the impact of short-term nitrate-rich dietary supplementation on endothelial function in COPD: A randomized crossover study.
- Efficacy of dietary nitrate-rich beetroot juice supplementation in patients with chronic obstructive pulmonary disease (COPD): A systematic review and meta-analysis.
- Efficacy and safety of nitrate supplementation on exercise tolerance in chronic obstructive pulmonary disease: A systematic review and meta-analysis.
- Effect of nitrate treatment on functional capacity and exercise time in patients with heart failure: a systematic review and meta-analysis.