Beyond relentless physical preparation and intense mental drills, an expanding body of research points to a deeper factor at play: a shared personality trait shaped not by résumés or training records, but embedded in human DNA.
What strength and stamina fail to explain
When people picture special forces or elite military units, familiar traits come to mind: exceptional fitness, unshakable focus, and strict discipline. These qualities are essential. Elite soldiers must run farther, think faster, and endure more than most individuals ever will.
However, a recent study published in Physiology & Behavior, examining members of US special operations forces, indicates that physical power and intelligence alone do not fully explain who survives the most demanding selection programs.
The findings reveal that elite soldiers consistently share a measurable trait: extraordinary resilience under pressure, closely associated with specific genetic patterns.
This resilience goes beyond the vague idea of “mental toughness.” It appears in how the brain regulates stress, how hormones are released, and how the body manages sleep loss, fear, pain, and high-stakes decision-making.
Inside the research: genes, data, and extreme stress
The research involved approximately 800 male soldiers with an average age of 25, all enrolled in an exceptionally punishing selection course for elite roles. Blood samples were taken to analyse each participant’s genetic profile.
Researchers concentrated on 47 genes already linked to:
- Brain function and cognitive performance
- Sleep cycles and circadian rhythms
- Hormone regulation and stress response
These genetic markers were compared against performance under intense physical and psychological strain. Scientists monitored cognitive tasks, emotional stability, physiological signals, and overall effectiveness throughout the selection process.
The results showed clear associations between certain genetic variations and differences in cognitive ability, psychological resilience, and physiological stress response.
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Put simply, some individuals appear biologically better equipped to adapt to the extreme demands of special forces selection.
Resilience as the defining genetic advantage
The most prominent trait identified was resilience: the capacity to sustain performance, sound judgment, and emotional control despite severe fatigue and stress.
Highly resilient soldiers were less likely to mentally collapse when deprived of sleep, injured, or under threat. They maintained focus, processed information efficiently, and continued making decisions while others froze or panicked.
Several genes were strongly associated with this heightened resilience:
- COMT – Regulates dopamine levels, influencing motivation, focus, and pressure tolerance
- TPH2 – Supports serotonin production, affecting mood stability and anxiety regulation
- PER3 – Linked to circadian rhythms, influencing performance during disrupted sleep
These genes do not act independently, nor do they create elite soldiers on their own. The study suggests that certain genetic variations may provide a natural advantage when facing prolonged, high-intensity stress.
Genes and training: how elite performance really develops
The findings raise an important question: if resilience has a genetic component, are elite soldiers born rather than developed? The researchers urge caution.
Genetics appear to shift the odds, not determine outcomes. Training, experience, and mindset remain critical. A person who trains consistently, manages stress effectively, and develops strong coping strategies can achieve high performance even without an ideal genetic profile.
However, individuals who combine rigorous preparation with favourable genetics may maintain peak performance longer, especially under extreme conditions. This helps explain why two equally fit and motivated soldiers can respond very differently to the same ordeal.
During identical sleep-deprived exercises, one may stay calm and focused, while the other begins to make errors, lose emotional control, or shut down mentally.
Improving resilience beyond genetic limits
Although genes influence baseline resilience, they do not set fixed limits. Military psychologists and performance specialists often strengthen resilience through targeted approaches.
Mental conditioning techniques
- Breathing exercises to stabilise heart rate and calm the nervous system
- Visualisation to rehearse high-stress scenarios in advance
- Cognitive training to sharpen focus and decision-making
- Gradual stress exposure with increasing intensity
Physical and biological support
Structured sleep routines, proper nutrition, hydration, and rest all affect how the brain manages dopamine and serotonin, and how hormonal systems respond to stress. Even individuals with less favourable sleep-related genes, such as certain PER3 variants, can reduce fatigue through disciplined habits.
Social and emotional foundations
Strong bonds within a unit, supportive leadership, and a clear sense of purpose all reinforce resilience. Soldiers who feel connected and supported often tolerate hardship more effectively, regardless of genetics.
How genes translate into everyday behaviour
To non-specialists, gene names like COMT and TPH2 may seem abstract, yet they relate directly to daily experiences.
A well-regulated dopamine system can help someone stay motivated during chaotic deadlines. Stable serotonin balance may support quicker emotional recovery and better control of fear or anger. Flexible body-clock genes can reduce cognitive decline during irregular sleep schedules.
In elite military environments, these subtle advantages accumulate. They can determine the difference between a clear-headed decision and a costly mistake under pressure.
Why these findings matter beyond the military
The same biological systems that support special forces performance also affect civilians. High-pressure professions such as emergency medicine, firefighting, aviation, and law enforcement face similar demands: rapid decisions, limited sleep, and sustained stress.
Recognising natural differences in resilience may influence how organisations approach training and support. It suggests more personalised strategies that align roles, schedules, and resources with individual strengths.
This research also raises ethical concerns. Genetic screening for high-pressure roles introduces questions about privacy, fairness, and discrimination. While most militaries reject genetic selection, scientific progress is making these debates increasingly relevant.
A practical illustration under extreme conditions
Imagine two candidates on a selection march: 40 kilometres, heavy packs, minimal food, and almost no sleep. Both trained extensively. Both are equally determined.
As night temperatures drop and exhaustion deepens, one begins misreading maps and snapping at teammates. The other, equally fatigued, maintains clarity, communicates calmly, and keeps the group organised.
The difference may not appear in fitness tests or motivation. At a molecular level, however, their brains process stress differently, shaped in part by subtle genetic variations highlighted in this study.
For anyone facing intense pressure, the message is not about destiny, but margins. Genes may influence starting position, but training choices, daily habits, and support systems determine how far someone ultimately goes.
