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How EPAS1 Shapes Power and Endurance

Power and endurance are two sides of athletic performance. Power is about short bursts of high intensity. Endurance is about sustaining activity over time. The EPAS1 gene helps the body respond to low oxygen by controlling red blood cell production and oxygen delivery to muscles. Small differences in this gene can change how efficiently your body uses oxygen during exercise, which can influence both power and endurance.

What this means for your training and health

Genetics is only one factor. Your training habits, nutrition, sleep, environment, and overall health also matter. Regardless of your EPAS1 variant, you can take practical steps to support oxygen delivery and performance: eat a balanced diet with iron and antioxidants, stay well hydrated, get regular aerobic and strength training, and monitor important blood markers. Below are targeted interpretations based on the rs11689011 genotype and actionable recommendations to help you make the most of your fitness potential.

Two effect alleles (CC) — Reduced oxygen efficiency

Genetic interpretation

If you have the CC genotype at rs11689011, you carry two copies of the effect allele. This pattern is associated with reduced efficiency in oxygen utilization during exercise. EPAS1 influences red blood cell production and oxygen delivery. With this genotype your body may struggle more than average to deliver oxygen to active muscles during both short, intense efforts and prolonged activity.

Implications

  • Potential for lower natural power output during maximal sprints or lifts.
  • Possible decreased endurance capacity for long duration efforts, especially in low oxygen or high altitude environments.
  • Increased importance of optimizing oxygen delivery through lifestyle and nutrition.

Practical recommendations

  • Diet: Prioritize iron rich foods such as lean red meat, poultry, fish, legumes, and dark leafy greens. Pair plant iron with vitamin C rich foods to enhance absorption.
  • Antioxidants: Include berries, citrus, dark chocolate in moderation, nuts, and green tea to support recovery and protect blood vessels.
  • Hydration: Maintain consistent hydration before, during, and after training to support blood volume and circulation.
  • Training: Emphasize a mix of aerobic base training and interval work. Include progressive overload in strength training to improve muscular efficiency and oxygen extraction.
  • Altitude and heat: Be cautious with high altitude exposure. If traveling to altitude, allow extra time for acclimation and consider staged increases in training load.
  • Supplements: Consider iron supplementation only if testing shows deficiency. Other options to discuss with your provider include vitamin C, B12 if needed, and general multivitamins to support energy metabolism.
  • Monitoring: Check hemoglobin, hematocrit, ferritin, and vitamin B12 levels periodically, especially if you train heavily or notice symptoms like excessive fatigue.
One effect allele (CT) — Moderate influence on oxygen use

Genetic interpretation

If you have the CT genotype at rs11689011, you carry one copy of the effect allele. This suggests a modest alteration in how EPAS1 regulates red blood cell production and oxygen delivery. The effect on performance is typically smaller than with two effect alleles, but it may still influence both power and endurance to some degree.

Implications

  • A slight tendency toward reduced oxygen efficiency during maximal or prolonged efforts compared with some other genotypes.
  • Performance remains highly modifiable through targeted training and nutrition.

Practical recommendations

  • Diet: Include regular servings of iron rich foods and support iron absorption with vitamin C. Maintain a nutrient dense pattern to fuel training and recovery.
  • Antioxidants: Regularly include fruits and vegetables high in antioxidants to reduce oxidative stress from training.
  • Hydration: Focus on daily fluid balance and electrolyte replacement during long sessions.
  • Training: Blend aerobic endurance work with high intensity intervals to improve mitochondrial efficiency and oxygen utilization. Continue regular strength training to increase muscle oxygen extraction capacity.
  • Supplements: Test before supplementing iron. Consider vitamin D, B vitamins, and omega 3 if diet is low in these nutrients and after discussing with your healthcare provider.
  • Monitoring: Periodic blood tests for ferritin, hemoglobin, and other markers can help you fine tune diet and supplementation.
No effect alleles (TT) — Typical EPAS1 function

Genetic interpretation

If you have the TT genotype at rs11689011, you carry two copies of the non-effect allele. This is associated with typical EPAS1 function, meaning your body regulates red blood cell production and oxygen delivery in a standard manner. This supports both power and endurance capacities under normal conditions.

Implications

  • Generally normal oxygen utilization during exercise and at moderate altitudes.
  • Performance outcomes will depend more on training, nutrition, and other non-genetic factors.

Practical recommendations

  • Diet: Maintain a balanced diet with adequate iron sources and antioxidants to support training and recovery.
  • Training: A balanced program with aerobic conditioning, interval training, and strength work will support both power and endurance goals.
  • Hydration: Keep consistent daily hydration and adapt fluid intake to workout intensity and climate.
  • Supplements: Routine supplementation is not required based solely on genotype. Use testing and clinical context to guide any additions.
  • Monitoring: Run bloodwork if you experience unexplained fatigue, performance drops, or if you plan prolonged altitude exposure.

Common blood tests to consider

  • Complete blood count with hemoglobin and hematocrit to assess oxygen carrying capacity
  • Ferritin to assess iron stores
  • Serum iron, transferrin saturation when indicated
  • Vitamin B12 and folate if diet is restricted
  • Vitamin D if you have limited sun exposure or recovery concerns

Training tips to maximize oxygen use

  • Build an aerobic base with long steady sessions to improve capillary density and mitochondrial function.
  • Use high intensity interval training to raise maximal oxygen uptake and power output.
  • Include strength training to increase muscular efficiency and support high power efforts.
  • Allow adequate recovery and sleep to support red blood cell turnover and repair.
  • If training at altitude, use gradual acclimation and reduce intensity until adapted.

Nutrition and supplement summary

  • Iron: Prioritize dietary iron. Supplement only after lab confirmation of deficiency and under professional guidance.
  • Vitamin C: Helps non heme iron absorption when eaten with plant based iron sources.
  • B Vitamins: Support energy metabolism. Test and supplement if levels are low.
  • Antioxidants: Daily fruits and vegetables provide protection and aid recovery.
  • Hydration and electrolytes: Tailor fluids to workout duration, sweat rate, and environment.

Final notes and important disclaimer

PlexusDx provides education about genetic predispositions and how genes like EPAS1 can influence traits related to power and endurance. This information is for educational purposes only and is not medical advice. Always consult with your healthcare provider before making changes to your medications, supplements, training plan, or if you have concerns about blood tests or health conditions. Your genotype is one piece of the puzzle. Combining genetic insight with professional medical guidance, personalized testing, and consistent lifestyle habits will give you the best chance to achieve your fitness goals.