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How ACE (rs4343) Affects Endurance and What You Can Do About It

Endurance is the ability to sustain physical activity for long periods by efficiently using oxygen and maintaining muscle function. The ACE gene plays a role in endurance by helping regulate blood pressure and supporting capillary growth inside muscles, which improves oxygen delivery during exercise. Variants at rs4343 in ACE influence how well your body adapts to endurance training. Below we explain what each genotype means and provide practical guidance on diet, supplements, training, hydration, recovery, and testing to help you make the most of your genetic predisposition.

Two effect alleles (AA genotype) — higher natural endurance potential

Your AA genotype at rs4343 means you carry two copies of the A allele, sometimes called the I or insertion variant. This pattern is associated with a favorable endurance profile. People with AA often show enhanced aerobic capacity and a tendency to respond well to long-duration aerobic training.

How this may affect you

  • Better capillary growth and oxygen delivery to muscle during prolonged exercise
  • Potentially stronger adaptations to endurance training such as improved VO2 max
  • May excel at long-distance running, cycling, swimming, and other aerobic sports

Recommended focus

  • Prioritize aerobic volume: build weekly mileage or time gradually with a mix of steady-state and long sessions
  • Include tempo runs, threshold rides, and aerobic base work to maximize endurance adaptations
  • Maintain strength training to protect muscles and improve economy
One effect allele (AG genotype) — moderate endurance advantage

With the AG genotype you carry one copy of the A allele. This gives a balanced profile that supports both endurance and power traits. Your physiology may respond well to both aerobic and mixed training, offering versatility across different types of exercise.

How this may affect you

  • Balanced capacity for endurance and power based activities
  • Good responsiveness to a combination of aerobic and higher-intensity work
  • Potential for strong improvements with structured, varied training

Recommended focus

  • Combine base endurance work with interval sessions to advance both aerobic and anaerobic systems
  • Use polarized training models: most volume at easy pace plus one or two high-quality sessions per week
  • Keep regular strength and mobility sessions to support performance and reduce injury risk
Zero effect alleles (GG genotype) — lower natural endurance predisposition

People with the GG genotype carry two copies of the non-effect allele. This pattern is commonly associated with a lower natural predisposition for endurance adaptations and a relative advantage for power-based activities.

How this may affect you

  • May be naturally better suited to shorter, higher-intensity, power-focused activities
  • Endurance adaptations are still possible but may require more structured training and consistency
  • Performance is influenced by many factors beyond genetics including training, nutrition, sleep, and recovery

Recommended focus

  • Emphasize progressive aerobic training with careful dose management to build endurance over time
  • Include longer slow runs or rides to increase capillary density and mitochondrial efficiency
  • Use strength training to improve power and support endurance sessions; consider technique and pacing work

Nutrition to Support Endurance

A balanced diet that supports energy demands and recovery is essential for all genetic backgrounds. Focus on whole foods, steady carbohydrate availability for training, and nutrients that reduce inflammation and oxidative stress.

  • Carbohydrates: prioritize complex carbohydrates around training for sustained energy. Include whole grains, potatoes, oats, fruits, and legumes.
  • Protein: aim for 1.2 to 1.8 g/kg body weight per day depending on training load for muscle repair and adaptation. Include lean meats, fish, dairy, eggs, legumes, and plant proteins.
  • Healthy fats: include omega-3 rich sources such as fatty fish, walnuts, and flax to support cardiovascular health and reduce inflammation.
  • Antioxidant and anti-inflammatory foods: colorful vegetables, berries, leafy greens, turmeric, and green tea help manage exercise-induced oxidative stress and support recovery.
  • Timing: consume carbohydrates and protein within a 30 to 120 minute window after longer training sessions to replenish glycogen and support muscle repair.

Supplements That May Help

Supplements can complement diet and training, particularly when nutrient intake is incomplete or training load is high.

  • Omega-3 fatty acids: may improve blood flow and reduce inflammation. Typical doses range from 1 to 3 g combined EPA and DHA daily.
  • Beetroot juice or nitrate supplements: can enhance blood flow and improve oxygen delivery to muscles, which may boost endurance performance.
  • Iron: monitor if you are at risk for deficiency, especially female athletes or those with heavy training loads. Only supplement after testing and under provider guidance.
  • Electrolyte formulations: useful during long sessions to maintain hydration and muscle function.
  • Vitamin D and magnesium: support muscle function and recovery when deficient.

Training and Lifestyle Recommendations

  • Progressive overload: increase duration and intensity gradually to promote capillary growth and mitochondrial density without overtraining.
  • Mix training types: combine long steady sessions, tempo work, and intervals to develop both aerobic base and race-specific fitness.
  • Strength training: 1 to 2 sessions weekly to improve muscular endurance, joint resilience, and running or cycling economy.
  • Sleep and recovery: prioritize 7 to 9 hours of quality sleep, active recovery, and periodized rest weeks to allow adaptations.
  • Hydration: maintain fluid balance before, during, and after exercise to support blood volume and performance.

Tests and Monitoring

  • VO2 max or lactate threshold testing: useful to track endurance capacity and guide training intensities.
  • Iron studies and vitamin D testing: identify deficiencies that impair endurance and recovery.
  • Resting heart rate and heart rate variability: simple daily metrics to monitor training load and recovery status.
  • Performance logs: track training volume, perceived exertion, and recovery to detect progress or early signs of overtraining.

Putting It Together

Your ACE rs4343 genotype provides one piece of the endurance puzzle. Whether you have AA, AG, or GG, consistent, well-structured training plus targeted nutrition, hydration, recovery, and appropriate supplementation will help you reach your goals. Use your genetic information to tailor emphasis and expectations, not to limit what you can achieve. Everyone can improve endurance with the right plan and commitment.

PlexusDx does not provide medical advice. This information is educational only and is not a substitute for professional medical evaluation, diagnosis, or treatment. Always consult your healthcare provider or a qualified professional before starting new supplements, making major changes to your diet, or beginning a new training program.