A University of Victoria dissertation reveals that running longer than 90 minutes alters specific cognitive functions and brain activity after exercise.
On September 14, 2026, the University of Victoria scheduled Katherine Boere’s neuroscience PhD defense, presenting new findings on how prolonged endurance exercise impacts the brain. The dissertation, titled "The Effects of Prolonged Running on Cognitive Performance and Brain Activity," examines aerobic efforts lasting more than 90 minutes. Under the supervision of Dr. Olav Krigolson, Boere used electroencephalography alongside cognitive tests to map domain-specific neural shifts. The research provides emerging evidence that extreme workouts differentially impact distinct mental functions based on task difficulty and energy availability.
Exercise science has extensively documented the cognitive benefits of short training sessions. However, Boere’s research specifically targeted running durations exceeding the 90-minute threshold. The methodology paired behavioral tests with electroencephalography, or EEG, to detect underlying neural changes. This dual approach allowed researchers to observe whether brain activity changed even when outward performance appeared completely stable.
The dissertation separated cognitive performance into distinct domains rather than treating mental clarity as a single metric. By measuring working memory, executive control, and reward sensitivity, the experiments revealed nuanced responses to intense physical fatigue. Researchers assessed participants across multiple extreme endurance contexts to gather diverse, real-world data. These specific testing scenarios included a two-hour treadmill run, a full marathon, and a 50-kilometre ultramarathon.
Each context provided a unique lens on how prolonged energy expenditure alters the brain. The inclusion of field-based races helped capture the true physiological toll of extreme endurance events. In the first experiment, participants completed a two-hour treadmill run followed by intensive 24-hour recovery testing. Performance on a 2-back working-memory task remained entirely unchanged.
However, EEG readings showed that frontal-theta activity increased one hour after the exercise concluded. The dissertation uses this frontal-theta increase as a measurable marker of greater cognitive effort. This indicates that the brain worked significantly harder just to maintain basic baseline performance. For ambitious professionals, balancing these physical efforts is essential for sustainable executive performance.
The research quantified how pushing past the 90-minute mark alters processing speed and response accuracy. In the second experiment, Boere assessed executive function before and after a grueling 50-kilometre ultramarathon. Athletes demonstrated faster reaction times following the race. Yet, this speed came with a severe cost, as their responses showed 14% greater variability.
Simultaneously, EEG measures associated with inhibitory control and attentional allocation, specifically N2 and P3 event-related potentials, measurably declined. The third experiment evaluated low-load and high-load working memory in female participants around a marathon event. Reaction times again improved, but accuracy on the more demanding 3-back task decreased. Frontal-theta activity increased during both low-load and high-load testing conditions.
These findings highlight a critical disconnect between feeling physically energized and actually processing complex information accurately. Faster behavioral responses do not inherently equal better analytical reasoning. Energy availability played a clear role in shaping these measured cognitive outcomes. The dissertation reports that the risk of chronic low energy availability predicted measurable declines in working-memory accuracy.
Furthermore, lower carbohydrate intake during the race and longer race durations predicted greater cognitive effort. In a fourth experiment on reward sensitivity, lower in-race carbohydrate intake was associated with larger post-race increases in neural sensitivity to feedback. This neural sensitivity was measured through reward-positivity amplitude, showing a direct link between physical fueling and brain activity.
Many leaders rely on long weekend runs to build their baseline energy and physical performance. The findings from the University of Victoria suggest we must treat exercise exceeding 90 minutes as a distinct cognitive state. While shorter exercise bouts generally support immediate mental focus, prolonged efforts demand highly careful scheduling. Executives should avoid placing major negotiations or complex strategy sessions immediately after an extreme endurance workout.
Instead, professionals must wait until they understand their own unique recovery patterns. During the toughest quarter of my career, I noticed that my ability to handle stress was directly tied to my cardiovascular fitness, not my mindset. I was trying to meditate my way out of a physiological deficit. Once we started looking at the data connecting aerobic capacity to emotional regulation and executive function, everything clicked.
Physical capacity is the absolute foundation of mental resilience. However, this new research reminds us that building that baseline capacity exacts a temporary cognitive tax. Leaders must build a reliable daily structure that accounts for this acute recovery window. Relying on perceived productivity is insufficient when high-load reasoning is required for strategic business decisions.
Track practical cognitive markers after long sessions, noting any distractibility, decision errors, or unusual effort required for routine analysis. Organizations should also consider placing structured recovery time between extreme endurance events and high-consequence corporate work. If an endurance event is necessary before critical work, treat fueling as a primary cognitive defense strategy. Prioritize adequate carbohydrate intake to support your wider nutrition and metabolic performance.
Separate the subjective feeling of being mentally clear from the objective reality of high-load reasoning capacity. The dissertation makes it clear that you can feel fast and responsive while simultaneously struggling with complex working memory. True executive functioning relies on accuracy and consistency, not just speed.
The University of Victoria explicitly characterizes these findings as tentative evidence. As a dissertation defense summary, the available data does not represent a full peer-reviewed journal publication. Complete methodologies, statistical models, and confidence intervals are not yet publicly available for independent review. Readers should view these insights as preliminary research rather than finalized scientific doctrine.
The experimental contexts were highly specific, focusing on a two-hour treadmill run, a marathon, and an ultramarathon. These extreme scenarios cannot automatically be generalized to every long workout or every professional operator. Furthermore, the experiments featured different samples and testing conditions across the multiple studies. The marathon working-memory experiment utilized an all-female sample, and the reward-sensitivity study included participants disproportionately at risk for low energy availability.
It is vital to avoid using this dissertation to justify aggressive supplementation or specific carbohydrate targets. The university summary notes statistical associations rather than establishing definitive physiological causation. ExecuFuel prioritizes clear evidence over assumed rules, and this research should inform personal tracking rather than universal medical conclusions. Operators should focus on understanding their own baseline performance before making drastic changes to their fueling strategies.
Sports neuroscience is clearly shifting away from treating mental performance as a single, uniform outcome. Future clinical trials will likely separate working memory, executive control, and reaction speed into distinct testing variables. This granular approach prevents researchers from missing underlying cognitive costs that simple reaction-time tests completely overlook. This represents a significant step forward for professionals who demand precise data to manage their cognitive capacity.
As mobile EEG technology becomes more sophisticated, we expect to see more field studies during actual athletic events. The role of energetic context will also drive upcoming investigations into human performance. Research is beginning to clarify exactly how low energy availability impacts concentration and high-stakes judgment. Future studies may establish precise recovery windows, helping operators understand exactly when high-load reasoning reliably returns to baseline.
Until then, leaders should prioritize cautious scheduling and careful self-monitoring to manage the transition from extreme endurance training to demanding executive work. The goal is to build physical resilience without compromising the cognitive bandwidth required to lead effectively.
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