Are you built for distance or speed?

Monday, April 23, 2018. Author Alex Auld

Unzipping My FitnessGenes: ACE

This blog series highlights and discusses the individual results of FitnessGenes Partnership Program manager and multi-event endurance athlete, Alex Auld.

Now that we’ve established how DNA regulates protein production, we can look at which proteins are produced by which genes, and the impact they have on exercise, nutrition and physiology.

This blog will look at ACE, the first gene that was shown to influence aspects of fitness and therefore one of the most widely researched genes to date.

ACE: A gene for endurance

For some people, continuous aerobic training is as far from a good time as they can imagine: hours upon hours of repetitive movement in all weathers and across all terrains, constantly having to battle against physical and mental fatigue. Why would you put yourself through it?

Others love it and almost seem built for it. I’m part of the latter group.

Natural preference for endurance exercise and activity can be, in part, explained by unlocking your ACE gene.

ACE is a gene associated with aerobic capacity and muscle fiber type, with one of the ACE variants (alleles) commonly found in elite endurance athletes.

ACE and Angiotensin II

The ACE gene regulates the production of the ACE (Angiotensin Converting Enzyme) protein, which in turn is responsible for the production of Angiotensin II.

The presence of Angiotensin II causes blood vessels to constrict, increases blood pressure and encourages fluid retention; all things that negatively impact endurance performance.

Having low levels of ACE protein, and consequently Angiotensin II, is therefore seen as a real advantage for endurance performance and response to continuous training.

People who carry two copies of the ACE 'I' allele have been shown to produce the lowest levels of ACE, while those who carry two copies of the ACE ‘D’ allele produce the highest levels.

My result: ID

The two alleles (or genetic variants) of ACE are:

  • I = Endurance
  • D = Power/strength 

Similar to my UCP2 (a gene for metabolism) result, I am heterozygous for ACE and carry one of each allele. This suggests that I produce intermediate levels of ACE protein and have a natural propensity for both endurance and power/strength-based events. My ID genetic make-up or ‘genotype’ for the ACE gene is also shared by 46% of the global population.

My result also suggests that, by carrying one copy of each allele, I have an even distribution of slow and fast-twitch muscle fibers and would respond well to both high volume/low intensity and low volume / high-intensity training methodologies.

This result was a real surprise for me, as I was certain that I would carry two copies of the endurance allele given my training background!

Other gene combinations: II and DD


As previously mentioned, people with two I alleles of the ACE gene produce the lowest levels of ACE and Angiotensin II. In complement to this, they have also been shown to carry a higher percentage of fatigue resistant slow-twitch muscle fibers and have a higher anaerobic threshold compared to those with ID and DD genetic makeups.

If you have the II genotype, you are therefore more likely to respond positively to continuous aerobic training or high volume / low-intensity resistance training. So, plenty of sets and reps per workout!


Conversely, and due to their increased ACE and Angiotensin II activity, people with the DD genotype are at a genetic disadvantage with regard to endurance capacity.

They do, however, have a higher percentage of fast-twitch muscle fibers, providing them with an advantage over II and ID genotypes when it comes to speed or power-based activity.

DD individuals are most likely to respond best to low volume / high-intensity workouts when looking to build muscle, or interval training over continuous training when looking to increase aerobic capacity.

Which variation do you carry?

By understanding how you are genetically engineered to respond best to certain types of training, you can structure your workouts accordingly. It may even be the case that those long hours on the treadmill or pounding the road are actually slowing your progress if it doesn’t suit your genotype!

Are you built for distance or speed? ACE is just one of the 41 genes we analyze at FitnessGenes. Click here to purchase your DNA Analysis or Genetic Workout System.

Need help choosing a plan?

Use our Plan Advisor to determine which genetically tailored diet and exercise program best fits your needs.

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