A University of Victoria PhD defense examines how prolonged running and race fueling affect cognitive performance, neural strain, and executive decision making.
On September 14, 2026, the University of Victoria scheduled Katherine Boere’s neuroscience PhD defense. The presentation examined the effects of prolonged running on cognitive performance and brain activity. Dr. Olav Krigolson supervised this online Medical Sciences event. The dissertation addressed a significant gap in current exercise cognition research.
Historically, most evidence centers on physical efforts lasting under sixty minutes. Studies analyzing exercise beyond ninety minutes often produce inconsistent results. Furthermore, those older studies rely almost entirely on basic behavioral tests. Boere utilized electroencephalography to track actual neural activity during and after prolonged acute exercise.
The resulting abstract provides a fascinating look into the brain of an endurance athlete.
The primary conclusion of this research fundamentally changes how we understand mental fatigue. Boere found that energetic status serves as a highly modifiable factor for brain function during endurance competition. In simple terms, the exact amount of fuel you consume dictates your mental sharpness late in a race. While these findings represent associations rather than strict causal proof, the abstract explicitly links the risk of chronic low energy availability to a measurable decline in working memory accuracy.
It also reports that lower carbohydrate intake during a race predicts greater cognitive effort. Your brain simply has to work much harder to process basic information when it lacks adequate energy. This hidden neurological effort often goes completely unnoticed if athletes only monitor their physical pacing. Basic reaction time tests can actually mask this underlying neural strain.
For example, athletes in the study recorded faster average reaction times after completing their endurance events. However, those faster initial reactions came with a significant increase in performance variability. Neural measurements proved that the brain was struggling internally even when behavioral responses seemed superficially quick. The combination of faster responses and greater variability complicates the assumption that a quick reaction indicates sharp cognition.
The researchers utilized electroencephalography to accurately measure brain activity across four distinct endurance environments. This advanced technology allowed the team to track neural changes that standard behavioral tests routinely miss. The experiments varied in distance and intensity to capture a broad picture of endurance fatigue.
The first experiment specifically tested working memory before and after a two hour treadmill run. Researchers then followed up with additional cognitive testing during the subsequent twenty four hours. Performance on a standard 2-back working memory task did not change at all. However, frontal theta activity increased significantly exactly one hour after the exercise concluded.
The dissertation uses this frontal theta activity as a direct measurement of cognitive effort. This distinction is incredibly important for long distance runners. It proves that a stable cognitive test score does not guarantee a fully rested brain. Neural measures can detect increased cognitive demand long before an obvious behavioral deficit appears.
The second experiment measured executive function around the demands of a fifty kilometre ultramarathon. After crossing the finish line, the participating athletes demonstrated noticeably faster reaction times. Yet, those faster reaction times showed 14 percent greater variability across the testing protocol. The post race results also highlighted specific reductions in the N2 and P3 event related potentials.
The abstract directly associates these reduced potentials with diminished inhibitory control and attentional allocation. A faster trigger finger simply does not equal better executive decision making under extreme fatigue.
The third experiment assessed female participants immediately before and after a standard marathon distance. Researchers utilized both low and high load working memory tasks to gauge mental fatigue. Reaction times improved once again, but accuracy dropped significantly on the high load 3-back task. The abstract notes that the risk of chronic low energy availability predicted these notable accuracy declines.
Furthermore, longer overall race durations and lower carbohydrate intake predicted substantially higher cognitive effort. The brain was forced to recruit more resources just to handle the same baseline tasks. The researchers discovered a clear inverse relationship between fueling volumes and total cognitive effort. Athletes who consumed fewer carbohydrates forced their brains to work much harder to process information.
The final experiment carefully examined reward sensitivity before and after a full marathon effort. Group level reaction times remained completely unchanged during this specific neural reward test. However, neural sensitivity to external feedback increased measurably after the race concluded. This was measured directly by observing the amplitude of reward positivity in the brain.
Lower in race carbohydrate intake was associated with much larger increases in this reward amplitude. The dissertation therefore links prolonged running to distinct changes in complex neural reward processing.
This emerging science requires ambitious older athletes to completely rethink their race day preparations. We often treat fueling solely as a physical necessity to maintain our desired goal pace. We worry obsessively about muscular cramps, glycogen depletion, and the dreaded physical bonk. Yet, Boere’s findings strongly suggest that our neural architecture also demands consistent carbohydrate delivery.
Lower in race carbohydrate intake directly correlates with greater cognitive effort. When your brain is starved for energy, your ability to focus and react smoothly deteriorates. This mental decline is exactly what causes poor tactical decisions late in very long events. A momentary lapse in focus on a technical trail descent can instantly ruin a season.
Your brain requires a steady supply of glucose to maintain high level executive function. When you force your body into a deep caloric deficit during a race, your nervous system responds by conserving energy. This conservation effort manifests as increased neural strain and a diminished ability to process complex variables. If your brain is actively starving, those critical milliseconds of reaction processing are severely compromised.
Failing to process your pacing data correctly at mile twenty will easily ruin a marathon. Hitting my forties brought a harsh reality check. The track workouts were not getting slower, but the days after them felt significantly heavier. Instead of forcing my old Tuesday and Thursday intensity schedule, I looked at the data on Masters athletes and muscle protein synthesis.
I pushed my second hard session to Friday, allowing an extra forty eight hours of low intensity recovery. My total weekly volume stayed the same, but the quality of my intervals skyrocketed. We must apply this exact same methodical adaptation to our nutritional and fueling strategies. The broader sports medicine community increasingly recognizes the severe dangers of chronic under fueling.
The 2023 International Olympic Committee consensus reviewed more than 170 original research publications on relative energy deficiency. It introduced the REDs Clinical Assessment Tool Version 2 to better manage athlete health. The consensus explicitly identifies impaired cognition and mood as potential consequences of energy deficiency in sport. Treating chronic low energy availability as a simple weight management tactic is a massive strategic error.
We need to respect the intricate connection between muscular endurance and executive function. A small crossover cycling study recently highlighted the performance benefits of proper carbohydrate fueling. It found that consuming 60 grams per hour of glucose increased cycling time to task failure by approximately 25 percent versus a placebo. While that study tracked physical task failure, the parallel to cognitive preservation is critical.
Proper fueling protects your leg speed while simultaneously preserving your essential mental clarity. This research should prompt you to build a proper race day contingency plan. Stop waiting until the final weeks to guess at your exact carbohydrate needs. Use these academic findings to justify highly individualized fueling experiments during your long training blocks.
You must establish what your brain and gut can comfortably tolerate long before reaching the start line. You can learn how to structure this appropriately by reviewing our training fueling vs race fueling framework. Ambitious athletes must begin monitoring much more than just their split times and heart rates. Start recording your perceived mental effort, pacing errors, and decision making quality after long sessions.
If you notice persistent mental fatigue, you must investigate your total energy availability immediately. This is about staying sharp enough to compete safely and effectively for several decades. Understanding the true elite fueling needs vs recreational reality is a crucial step in this process. Older athletes do not need professional carbohydrate volumes, but we absolutely require sufficient energy to protect our cognitive function.
Endurance athletes must treat adequate race fueling as a critical neurological requirement rather than just a physical tool for maintaining pace.
Follow ReEndure for practical insights on endurance training, recovery, nutrition and healthy aging. Stay connected for new articles, research led guidance and ideas to help you perform better for longer.
Read practical ideas on endurance training, recovery, nutrition and healthy aging to keep progressing for years to come.
Read the Blog