Understanding your personal Caffeine and endurance performance trait

Thursday, July 28, 2022. Author Alex Auld

Cyclist having a coffee bread during a bike ride

Having a hit of caffeine before a resistance-based workout, whether as a coffee or a pre-workout mix, can help to enhance exercise performance - a topic covered by our recent caffeine responsivity and building muscle trait. 

However, when taken before endurance-based training and events, not everyone benefits from caffeine in the same way. In fact, for some, consuming caffeine before a run or ride can actually have a detrimental impact on performance. 

To understand why, it’s important to first establish the impact that caffeine has on the body during exercise and the genetic factors that can influence its effect.

 

Caffeine and exercise

As well detailed in Dr Haran Sivapalan’s Caffeine and endurance performance blog, caffeine principally enhances exercise performance through the stimulation of the central nervous system. By causing the stimulation of dopamine receptors, caffeine helps to increase motivation and focus, reduce fatigue, and even lower our perception of how hard we're exerting ourselves. 

Caffeine has also been found to promote the release of calcium from muscle cells. Due to its role in facilitating muscle contraction, declining availability of calcium during exercise can cause fatigue and impair the force of muscle contractions. By promoting the release of additional calcium, this can help fight fatigue and sustain exercise performance. 

 

Caffeine and endurance performance genes

CYP1A2

The CYP1A2 gene encodes for a protein of the same name, whose primary function is to break down or ‘metabolise’ caffeine once it’s been consumed. The rate at which you metabolise caffeine can influence how quickly you experience its stimulating effects, and for how long. 

Those who carry the CYP1A2 AA genotype have been found to have greater activity of the CYP1A2 protein and are therefore classified as ‘fast metabolisers’. The opposite is true for those who carry the CC genotype, who have reduced CYP1A2 activity and are classified as ‘slow metabolisers’. The final heterozygous genotype, AC, sits between the other two and is associated with intermediate caffeine metabolism. 

ADORA2A 

In addition to how quickly caffeine is metabolised, your genetic code can influence how sensitive you are to its effects.

Studies have found that those who carry the ADORA2A TT genotype are much more likely to be sensitive to the stimulating effects of caffeine. This therefore places them at a greater risk of its unwanted side effects, such as sleep disturbance and anxiety. 

When the interaction of these genes is considered, this gives rise to six possible caffeine and endurance performance trait bands, between which all FitnessGenes members are grouped: 

 

1. Increased performance benefits from caffeine.

The most advantageous trait band for endurance performance and overall health. Members within this band carry the CYP1A2 AA genotype and are therefore classified as a fast metaboliser of caffeine.

Taking 3-6 mg of caffeine per kg of bodyweight can increase endurance performance by up to 8%.

 

2. Increased performance benefits from caffeine, high sensitivity. 

This band is also comprised of ‘fast metabolisers’ as a result of the CYP1A2 result and therefore experience greater endurance performance in response to caffeine consumption.

However, members within this band have also been identified as having high sensitivity to caffeine, which can increase their risk of sleep disturbance and anxiety if it is consumed at inappropriate times or in excessive quantities.

 

3. Smaller performance benefits from caffeine. 

Carriers of the CYP1A2 AC genotype and therefore classified as ‘intermediate metabolisers’ of caffeine. As a result, those grouped in this trait band are likely to experience smaller improvements in endurance performance compared to AA carriers.

However, as a result of their ADORA2A gene, this band is not at an increased risk of sleep disturbance or anxiety.

 

4. Smaller performance benefits from caffeine, high sensitivity. 

This band is also comprised of members who carry the CYP1A2 AC genotype and therefore are likely to experience smaller improvements in endurance performance when consuming caffeine relative to AA carriers.

With high sensitivity to the effects of caffeine, this band is at an increased risk of sleep disturbance and anxiety if caffeine is consumed at inappropriate times or in excessive quantities.

 

5. No performance benefits from caffeine. 

Members grouped within this trait band are classified as slow metabolsiers of caffeine as a result of carrying the CYP1A2 CC genotype. Consuming caffeine before endurance exercise may fail to improve, and can even worsen, exercise performance.

One randomised control trial found that cyclists with the CC genotype worsened their 10km time by 13.7% after consuming caffeine. 

 

6. No performance benefits from caffeine, high sensitivity. 

Members within this final trait band have the double disadvantage of decreased endurance performance in response to caffeine and an increased risk of sleep disturbance and anxiety.

Those within this trait band are advised to focus any caffeine consumption away from workouts and to avoid caffeine at least seven hours before going to sleep. 

 

Learn more about Caffeine and endurance performance

If you have already received your personal FitnessGenes results, your Caffeine and endurance performance trait, insights and actions are now live in your members’ area. Login in to learn more. 


Not yet a FitnessGenes member and want to discover if you should be taking caffeine before your endurance workouts or events? Purchase your DNA analysis or DNA upload from our website to access all 125+ traits currently available on truefeed, as well as all future releases.  

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