Genetic Variants Influencing Reaction Time, Decision-Making, and Neurocognitive Performance in Children
- James Walsh
- 6 days ago
- 7 min read
As someone who has been training professionally for over 17 years, I've seen a lot of different ways to develop athletes improve their strength, speed and agility and for the past 4-5 years I've noticed a decline in cognitive performance based reaction times, listening and processing habits. Read More on why I believe there's becoming a bigger issue with screentime.
Reaction time and decision-making ability emerge from a complex interplay of neural signaling, synaptic efficiency, motor planning, and emotional regulation. While environment and training exert the most powerful influence over these traits, several genetic variants have been linked to baseline predispositions. These variants do not predetermine outcomes but help explain individual differences in how children process information, regulate attention, and respond to dynamic situations in sport or daily life.
The Dopamine System: Regulating Focus, Working Memory, and Response Control
Dopamine is central to decision-making and the ability to process information efficiently. Children naturally vary in how quickly they break down dopamine in the brain, a difference influenced by a gene called COMT (catechol-O-methyltransferase).
Clinical Perspective
The COMT Val158Met polymorphism affects the speed of dopamine metabolism in the prefrontal cortex—an area responsible for working memory, cognitive flexibility, and executive control.
Val/Val carriers metabolize dopamine quickly, often resulting in fast responses but reduced stability under pressure.
Met/Met carriers metabolize slowly, often improving cognitive stability but slowing response speed.
Parent Perspective
This is why some children react instantly but get overwhelmed in chaotic moments, while others pause and think before acting. Both are normal profiles that respond well to targeted training.
Dopamine Receptor Variants: Influencing Attention and Exploratory Behavior
Two additional genes, DRD2 and DRD4, impact how the brain responds to dopamine signals.
Clinical Perspective
DRD2 variants can affect reward processing and reinforcement learning.
DRD4’s 7-repeat allele is linked to novelty-seeking, higher behavioral variability, and altered attention regulation.
Parent Perspective
Children with these traits may seem easily distracted or highly energetic, but they often thrive in dynamic, fast-moving environments. Structure and repetition help them develop consistency.
BDNF and Neuroplasticity: How Children Learn and Retain Skills
BDNF (Brain-Derived Neurotrophic Factor) is critical for synaptic growth and motor learning. A well-known variant, Val66Met, influences how efficiently BDNF is released during learning.
Clinical Perspective
Met carriers may exhibit slower early-phase skill acquisition but often retain skills well once learned due to enhanced long-term consolidation.
Parent Perspective
A child who learns slowly at first is not behind; they may simply require more repetition to establish neural patterns. With time, they often develop exceptional long-term mastery.
SNAP25 and Synaptic Timing: Coordination and Attention to Detail
The SNAP25 gene supports efficient neurotransmitter release at synapses—critical for timing, coordination, and attention regulation.
Clinical Perspective
Variants can influence attention control, action timing, and processing speed, affecting reaction latency in complex tasks.
Parent Perspective
This is why some children appear precise and coordinated, while others require additional repetitions to build timing accuracy.
ACTN3 and First-Step Quickness: The Neuromuscular Component
ACTN3 influences fast-twitch muscle fiber function and neuromuscular activation.
Clinical Perspective
The R allele supports rapid force production and explosive movement. X allele carriers lean toward endurance and may exhibit delayed initial activation.
Parent Perspective
First-step explosiveness is partly genetic but highly trainable. Early movement inefficiency does not mean lack of potential—it means the child may benefit from strength and speed training.
MAOA and Emotional Regulation Under Stress
MAOA regulates breakdown of dopamine, serotonin, and norepinephrine—chemicals that influence mood and stress response.
Clinical Perspective
Low-activity MAOA variants may predispose children to heightened emotional sensitivity and impulsive responses under stressful or chaotic conditions.
Parent Perspective
This can look like frustration, hesitation, or emotional swings during competition. With proper guidance—calm coaching, clear routines, and emotional support—these children often develop strong resilience.
What This Means for Youth Development and Training
1. Reaction time and decision-making are highly trainable
Children can dramatically improve through:
reaction drills
pattern recognition tasks
sport-specific decision-making scenarios
visual tracking and sensory integration
confidence-building environments
2. Every child has a unique processing style
Some children:
react fast but need help with accuracy
think deeply but need speed
learn quickly
learn gradually
All pathways are valid and develop well with consistent coaching.
3. Environment outranks genetics
Factors that significantly influence performance:
sleep quality
nutrition
emotional regulation
structured training
confidence
supportive adults
4. Parents play a vital role
Understanding a child’s natural tendencies reduces pressure and increases progress. Celebrate effort, allow learning curves, and focus on consistency rather than comparison.
The goal is not just to improve reaction time—it’s to build a confident, capable, adaptable athlete ready for the demands of sport and life.
Genetic traits such as COMT, DRD2/DRD4, BDNF, SNAP25, ACTN3, and MAOA are fixed variants. Supplements cannot “improve” or “change” genetic traits. What supplements can do is support healthier expression of related neurochemical pathways or optimize the physiological environment in which those genes operate.
Genetic traits such as COMT, DRD2/DRD4, BDNF, SNAP25, ACTN3, and MAOA are fixed variants. Supplements cannot “improve” or “change” genetic traits. What supplements can do is support healthier expression of related neurochemical pathways or optimize the physiological environment in which those genes operate.
Supplements Influence Pathways, Not Genes!
Supplements Supporting Neuromuscular Activation (ACTN3)
Creatine Monohydrate
How it works:Enhances phosphocreatine availability in fast-twitch fibers.
Evidence:Meta-analyses show improved sprint performance and explosive output (PMID: 12701815).
Relation to ACTN3:
Helps compensate for slower neuromuscular activation in X-allele carriers.
2. Beta-Alanine
How it works:Buffers intramuscular acid and improves high-intensity effort.
Evidence:Benefits repeated sprint performance (PMID: 17921429).
Youth caution:May cause tingling—use with professional oversight.
Pathway / Genetic Context (examples) | Goal | Conservative Nutrition/Supplement Options* | Pediatric Notes | Key Outcomes Parents Should Expect |
Dopamine turnover (COMT, DRD2/DRD4) | Maintain steady attention and decision quality under stress | Omega-3 (EPA/DHA); Vitamin D (if deficient) | Use diet-first; test vitamin D before dosing | Small to moderate gains in attention, less volatility under load |
Neuroplasticity & skill learning (BDNF Val66Met) | Support learning curves and consolidation | Creatine monohydrate; Curcumin (bioavailable forms) | Creatine only with clinician oversight; curcumin may interact with meds | Better practice tolerance; improved “stickiness” of skills |
Synaptic efficiency & timing (SNAP25) | Support working memory and timing | Magnesium L-threonate; Choline/Alpha-GPC (clinician-guided) | Avoid unsupervised cholinergics in youth | Smoother task switching; less timing “drift” when tired |
Neuromuscular activation (ACTN3) | First-step quickness, repeat sprints | Creatine monohydrate; Beta-alanine | Paraesthesia from beta-alanine is benign but uncomfortable | Faster starts; better repeat-effort quality |
Stress reactivity / emotional regulation (MAOA) | Calmer decision-making under pressure | Omega-3 (again); L-theanine; Rhodiola rosea (adolescent only, supervised) | Screen for medication interactions; avoid DIY “MAO” manipulations | Fewer “rushed” choices; more composure late in sessions |
*Always coordinate supplements for minors with a healthcare professional; prioritize sleep, whole-food nutrition, hydration, and training structure first.
Introducing Fitness DNA Testing: The Next Level of Athlete Insight
At Ground Force Strength and Conditioning Training Systems our mission is to give families the most complete and objective understanding of their athlete’s development. We’ve built the most comprehensive assessment program in North Florida—combining biomechanics, strength profiling, movement quality, sprint mechanics, cognitive reaction testing, and sport-specific performance markers. Now, we’re elevating that standard once again.
We are proud to introduce Fitness DNA Testing—a scientific tool designed to help parents and athletes gain a deeper understanding of their unique genetic tendencies. This testing does not predict success or label a child. Instead, it provides evidence-based insight into how an athlete’s body responds to training, recovers from stress, and adapts to different physical demands.
Fitness DNA results add another dimension to our assessment model by identifying predispositions—such as how efficiently the body processes dopamine, responds to training load, builds muscle, manages fatigue, or regulates stress. When combined with our on-field and in-lab testing, this information gives us the most complete performance profile available anywhere in North Florida.
For parents, it means clarity. For athletes, it means a smarter, more individualized plan. And for coaches, it means higher confidence that every training session is aligned with how the athlete’s body and brain naturally function.
This service is not about predicting outcomes. It’s about understanding the athlete at the deepest level so we can train them in the most effective, safe, and efficient way possible. Fitness DNA testing becomes one more lens through which we can see the whole athlete—helping us optimize their speed, strength, endurance, decision-making, recovery, and long-term readiness for sport.
Here is my a section of my personal overview:
Your genetic profile suggests you respond well to training strategies that emphasize moderate to fast repetition tempo and short to moderate rest intervals. These traits indicate your neuromuscular system tolerates a higher training density and benefits from consistent, rhythm-driven strength work.
You carry an ACTN3 variant associated with the absence of alpha-actinin-3 in fast-twitch fibers. This does not limit performance potential but may influence how your muscles generate explosive force. Athletes with this profile typically respond well to structured strength development, velocity-based training, and progressive sprint or power work.
Your results show gene variants connected to reduced lactate clearance (MCT1) and lower IGF-1–linked growth potential. Practically, this means you may require more strategic recovery planning and benefit from consistent strength exposure over time, rather than aggressive short-term loading.
Your mTOR-related hypertrophy potential is reported as intermediate. With well-designed programming, you can build muscle effectively using correct intensity, frequency, and progressions.
Nitric oxide pathways appear unrestricted, indicating no genetic hindrance to muscle growth from this mechanism.
Your TNF-α markers suggest an average response to muscle damage. You neither under-recover nor display elevated sensitivity to muscle breakdown; you sit closer to normative ranges.
Finally, your profile indicates that caffeine may be beneficial for training performance, though individual tolerance should be considered.
Starting in 2026 Ground Force Strength and Conditioning will be the LEADING SPORTS PERFORMANCE PROVIDER IN NORTH FLORIDA.
Pre-Oder your DNA Fitness Kit by submitting your request here.
References
DRD4 7-repeat allele & Reaction Time
Szekely A, et al. Genetic factors of reaction time performance: DRD4 7-repeat allele. Hum Genet 2011;130(2):193-201.Found that “slower responses characterized the group with the 7-repeat allele” in reaction time tasks (n = 245). PubMed
Gilsbach S, et al. Effects of the DRD4 genotype on neural networks in children/adolescents. Dev Cogn Neurosci 2012;2(Suppl 1):S165-S171. ScienceDirect
COMT Val158Met polymorphism & Cognitive / Decision-Making
BDNF Val66Met polymorphism & Motor Learning / Neuroplasticity
Egan MF, et al. The BDNF val66met polymorphism affects activity-dependent BDNF release and human memory/hippocampal function. Cell 2003;112(2):257-69. [classic study]
Kleim JA, et al. The BDNF val66met polymorphism appears to affect motor cortex plasticity in humans. J Neurosci 2006;26(40):10107-11. (see PMC) PMC+2Journal of Neuroscience+2
Sugiura L, et al. Age-dependent effects of COMT Val158Met polymorphism on brain structure in children. Cereb Cortex 2017;27(1):104-16. OUP Academic
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