HSA | FSA CARDS ARE NOW ACCEPTED

Last reviewed: May 12, 2026 Last updated: May 12, 2026

Written by: Jay Hastings , CEO of PlexusDx

Jay Hastings is the CEO of PlexusDx, a precision health company focused on genetic testing, blood biomarker insights, and personalized wellness recommendations. He has more than 20 years of experience across healthcare innovation, genomics, laboratory operations, healthcare investing, and strategic finance. His work has included scaling healthcare startups, leading CLIA lab integrations, and helping expand consumer access to precision health tools.

Medically reviewed by: Jayden Lee, PharmD, EMBA

Jayden Lee, PharmD, EMBA, is the PlexusDx Medical Science Liaison with a PharmD and MBA specializing in pharmacogenomics and clinical product development, with a proven ability to bridge the gap between genomic research and practical patient outcomes. Dr. Lee has more than 10 years of professional experience in clinical pharmacy, academia, and research.

How EPAS1 Affects Power and Endurance

Power and endurance are two key components of athletic performance. Power governs short, intense bursts like sprints and lifts. Endurance supports sustained activities like long runs, cycling, or team sports. The EPAS1 gene helps your body sense low oxygen levels and adjust red blood cell production to improve oxygen delivery to working muscles. That oxygen sensing system can influence how well you perform during both high intensity and prolonged exercise.

Why EPAS1 Matters

When muscles need more oxygen during exercise, your body signals to produce more red blood cells and change how it uses oxygen. EPAS1 is part of that oxygen sensing network. Variations in this gene can mildly change how efficiently oxygen is detected and delivered. That difference may affect stamina, recovery, and short-term power output, but it is only one factor among many. Training, nutrition, sleep, hydration, and overall health often have larger effects on athletic performance.

Practical Recommendations to Support Oxygen Use and Performance

Regardless of your EPAS1 genotype, these strategies help optimize oxygen transport, muscle function, and recovery. They are safe, practical steps you can discuss with your healthcare provider and include in your fitness routine.

Diet and Nutrition

  • Prioritize iron rich foods: lean red meat, poultry, fish, beans, lentils, tofu, fortified cereals, leafy greens. Iron supports hemoglobin and red blood cell production.
  • Include vitamin C with iron sources: citrus, bell peppers, strawberries, or kiwi to improve iron absorption from plant foods.
  • Eat antioxidant rich foods: berries, dark leafy greens, nuts, seeds, and colorful vegetables help manage oxidative stress from intense training.
  • Balance macronutrients: adequate carbohydrates fuel high intensity and endurance sessions; protein supports recovery and muscle repair.
  • Time meals around training: a light carbohydrate and protein snack 1 to 3 hours pre-exercise and a recovery meal within 45 to 90 minutes after training help performance and adaptation.

Supplements to Consider (Talk to Your Provider)

  • Iron: only if tests show low iron or iron deficiency. Unnecessary iron can be harmful.
  • Vitamin C: supports iron absorption and antioxidant capacity.
  • Beetroot juice or nitrates: may improve blood flow and exercise efficiency for some people.
  • Creatine: supports short term power and strength performance.
  • Omega 3 fatty acids: support recovery and overall cardiovascular health.

Training and Lifestyle

  • Combine aerobic and strength training: aerobic sessions build endurance and oxygen use, strength work improves power and muscle efficiency.
  • Include interval training: high intensity intervals improve both power and oxygen delivery systems.
  • Progress gradually: increase training load, volume, or intensity slowly to reduce injury and allow physiological adaptations.
  • Prioritize sleep: recovery and red blood cell production are supported by consistent, sufficient sleep.
  • Hydration: maintain fluid balance before, during, and after exercise to support blood volume and circulation.
  • Avoid sudden exposure to high altitude without acclimation: allow days to weeks for adaptation when traveling to higher elevations.

Blood Tests and Monitoring

  • Complete blood count (CBC): checks hemoglobin and hematocrit to evaluate oxygen carrying capacity.
  • Serum ferritin and iron studies: determine iron stores and detect deficiency.
  • Discuss testing frequency with your healthcare provider if you train intensely, feel unusually fatigued, or suspect iron deficiency.

EPAS1 Genetic Interpretations

2 effect alleles (GG) — two copies of the effect allele

If your genotype is GG for rs1867785, you carry two copies of the effect allele. This variant may modestly influence how efficiently your body senses low oxygen levels and produces red blood cells. Some people with this genotype report more challenge in oxygen transport during both intense and prolonged exercise. That can translate to slightly reduced endurance during long efforts and marginally lower power during short maximal efforts.

Actionable tips if you are GG:

  • Monitor iron status regularly and treat deficiency if present under clinician guidance.
  • Emphasize aerobic conditioning and interval training to enhance oxygen delivery and utilization.
  • Consider moderate altitude exposure only with gradual acclimation; avoid abrupt high altitude training without supervision.
  • Include nitrate rich foods like beetroot and consider a trial of beetroot juice under provider guidance to support blood flow.
  • Stay well hydrated and prioritize antioxidant rich foods to support recovery.
1 effect allele (AG) — one copy of the effect allele

If your genotype is AG for rs1867785, you carry one copy of the effect allele. This is associated with a mild variation in oxygen sensing and red blood cell regulation. You may experience a small difference in endurance or power compared to individuals without this variant, but for most people the effect is modest.

Actionable tips if you are AG:

  • Maintain a diet with sufficient iron and vitamin C to support red blood cell production.
  • Combine steady state aerobic workouts with higher intensity intervals to boost oxygen efficiency.
  • Use hydration, sleep, and recovery strategies to support performance on training and race days.
  • Consider monitoring ferritin and hemoglobin periodically if you train heavily or feel fatigued.
0 effect alleles (AA) — no effect alleles

If your genotype is AA for rs1867785, you carry two copies of the non-effect allele and have typical EPAS1 function. Your oxygen sensing and red blood cell production are expected to operate within the common range. This provides a normal baseline for power and endurance.

Actionable tips if you are AA:

  • Continue balanced training with both aerobic and strength elements to maximize performance.
  • Maintain iron rich foods and antioxidants to support recovery and oxygen use.
  • Monitor health indicators and blood work as needed, especially if you increase training load or experience symptoms like persistent fatigue.

Putting Your Genes in Context

Genetic results like EPAS1 provide one piece of the performance puzzle. Lifestyle factors frequently have larger impacts. You can often overcome modest genetic challenges through focused training, nutrition, sleep, hydration, and smart recovery. Use your genetic information to personalize your approach, not to limit your goals.

Important Disclaimer

PlexusDx provides educational information about genetic predispositions and potential strategies to support health and performance. PlexusDx does not provide medical advice. Always consult your healthcare provider before making changes to your diet, supplements, training program, or medical care. Your provider can help interpret genetic results alongside clinical history and lab tests to create a safe, effective plan tailored to you.

If this genetic variant is present in your PlexusDx results, the following tests and reports are commonly used to explore it further:

🧬 Genetic Tests:

🧪 Blood Tests:

📄 Genetic Report:

Frequently Asked Questions About Power and Endurance and EPAS1 rs1867785

How does EPAS1 rs1867785 affect power and endurance?

EPAS1 helps your body sense low oxygen and regulate red blood cell production to improve oxygen delivery to working muscles. Variations in EPAS1 (rs1867785) can mildly change how efficiently oxygen is detected and delivered, which may influence stamina, recovery, and short-term power output—though training, nutrition, sleep, hydration, and overall health usually have a larger impact.

What should I eat to support EPAS1-related oxygen use during training?

Prioritize iron-rich foods (lean red meat, poultry, fish, beans, lentils, tofu, fortified cereals, leafy greens) to support hemoglobin and red blood cell production, and include vitamin C with iron sources (citrus, bell peppers, strawberries, kiwi) to improve absorption. Add antioxidant-rich foods (berries, dark leafy greens, nuts, seeds, colorful vegetables) to help manage oxidative stress from intense training, and balance carbs and protein to fuel sessions and support recovery. Timing matters too: a light carb + protein snack 1–3 hours pre-workout and a recovery meal 45–90 minutes after can support performance and adaptation.

Should I take supplements for EPAS1, and what tests can confirm my needs?

Only consider iron if blood tests show low iron or deficiency—unnecessary iron can be harmful. Vitamin C can support iron absorption, and beetroot/nitrates may improve blood flow and exercise efficiency for some people. Creatine can support short-term power and strength, and omega-3s support recovery and cardiovascular health. For monitoring, ask your healthcare provider about a CBC (hemoglobin/hematocrit) and serum ferritin/iron studies to evaluate oxygen-carrying capacity and iron stores, especially if you train intensely or feel unusually fatigued.

What tests can help me learn more about Power and Endurance and EPAS1 rs1867785?

The Functional Health Genetic Test delivers over 750 personalized genetic insights across 10 in-depth genetic reports to support whole-body, systems-level health understanding. The Fitness and Injury Genetic Report translates your results into personalized, actionable guidance. Your healthcare provider can also recommend targeted blood tests based on your specific pathway results and health history to complement your genetic insights with current biomarker data.

Medical and Editorial Standards

Medical review process: This article was reviewed for medical accuracy, scientific clarity, evidence alignment, and appropriate discussion of genetics, medications, supplements, biomarkers, and health-related claims.

Sources and evidence: PlexusDx educational content is developed using peer-reviewed research, clinical literature, reputable medical references, and, where applicable, public health or regulatory guidance. References are included at the end of the article when scientific, medical, or health-related claims are discussed.

Commercial transparency: PlexusDx offers genetic testing, blood biomarker testing, personalized supplement recommendations, and related precision wellness services. Product mentions are intended to help readers understand available options and should not be interpreted as medical advice.

Important disclaimer: PlexusDx educational content is for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about medications, supplements, genetic testing, lab testing, or health-related care.