Does Your Brain Bonk After a Marathon?
Plus-Why women use Strava; 'cognitive warm-ups'; running stiffness; hydrogel carbs; and what we can learn from elite Ethiopian runners about training blocks.
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Does a Marathon Temporarily Change the Brain?
Every marathon runner knows the body feels different after 26.2 miles. The legs are trashed, the stairs become personal enemies, and the appetite can turn feral. A new study asks what happens to the brain.
This is not just a metaphorical “marathon brain” question. The authors had previously shown that marathon running was associated with reversible reductions in myelin content in specific areas of the brain (I covered the study in a previous RLRH newsletter). Myelin is the fatty insulation around nerve fibers that helps signals travel efficiently. That earlier finding naturally raised a big concern—if myelin temporarily decreases after a marathon, does brain function suffer?
The researchers studied marathon runners and non-running controls before the race, within 48 hours after the race, and again one month later. They combined neurophysiological testing, which looks at how quickly and strongly nerve signals travel, with cognitive testing across several domains.
The first major finding was that neural signal transmission appeared preserved. The researchers checked whether signals still moved normally through motor pathways, sensory pathways, visual pathways, and auditory pathways after the marathon. The answer was yes.
The cognitive results were more nuanced. Marathon runners did not show global “cognitive collapse” after the race. But they did show selective, temporary changes. On a test that measures processing speed, non-runners improved after repeat testing (because of practice), but runners showed a smaller immediate improvement after the race, suggesting the marathon blunted normal practice-related gains.
On a test that measures your ability to suppress an automatic response and stay focused on the correct one, non-runners again improved after repeated testing, while runners showed a temporary increase in interference after the marathon (they got a worse test score). By one month, the effect had normalized. Meanwhile, visuomotor speed, attention, and cognitive flexibility were all largely preserved after the race.
What this means for runners
A marathon does not appear to cause broad short-term brain dysfunction, but it may temporarily reduce your highest-level sharpness.
After a marathon or ultra, it is probably wise to treat the brain like the legs—functional, but not fully recovered. Don’t schedule your hardest work presentation, most complex decision-making, or emotionally charged life admin for the day after a major race if you can avoid it. Prioritize sleep, carbohydrates, hydration, and recovery because your brain has just helped coordinate an enormous metabolic event. This study also reinforces that endurance performance is a whole-body challenge, and the brain is not just along for the ride.
Does Strava Promote Unhealthy Training Habits?
Strava is not simply a fitness-tracking app. It is part training log, part social network, part scoreboard, part identity machine. And a new study suggests, for competitive female runners, that combination can be both motivating and psychologically messy.
The researchers wanted to understand why competitive female runners use Strava and how they perceive its effects on motivation, self-image, comparison, pressure, and well-being. Rather than running an intervention or collecting performance data, they conducted a qualitative study: 19 competitive female runners completed semi-structured interviews, and the researchers analyzed those conversations. The participants included professional runners, Olympic Trials qualifiers, and athletes actively trying to qualify. They ranged from 25 to 42 years old, averaged about 16 years of running experience, and reported nearly 47 miles per week in the month before the interview.
The big finding was that Strava carried three overlapping meanings for these runners.
First, Strava helped define their “running self.”
The athletes described the app as a kind of digital training diary, a place to document progress, reflect on workouts, track shoes and mileage, and look back before races for evidence that the work had been done.
Second, Strava created the experience of “being seen and seeing others.”
Participants described the platform as a meaningful way to stay connected to teammates, friends, competitors, and the broader running community. Kudos and comments were small forms of validation, and Strava sometimes prompted offline support, like texting a teammate after a big workout. But because everyone can see the run, the workout, the pace, the distance, and sometimes the heart rate, runners felt exposed. Several participants described worrying about what others would think if they struggled, ran slowly, took downtime, or appeared less fit.
The third theme may be the most interesting: runners curated the image of the “good runner.”
Even though many participants described Strava as more authentic than other social media platforms, they still admitted to managing what others saw. Some hid heart rate data if it looked too high for an easy run. Some made captions explaining why a run was slow. Some separated warm-ups and workouts or avoided posting certain runs altogether.
What this means for runners
Strava can be a great tool, but it needs boundaries. Use it as a training log, confidence file, and connection point, but be honest about when it starts making decisions for you.
If seeing other people’s workouts pushes you to run when you’re sick, injured, exhausted, or supposed to be recovering, the app is no longer serving your training. It is hijacking it. I’d encourage runners to periodically ask: “Would I still do this run if nobody could see it?” and “Am I posting this to reflect my training or to manage how people perceive me?” (These are questions I’ve asked myself as of late). There’s nothing wrong with sharing big workouts, race breakthroughs, or even the occasional humblebrag. But the healthiest runners are usually the ones who can keep the private purpose of training louder than the public performance of training.
Can a ‘Mental Warm-Up’ Make You Faster?
Warmups are meant to raise core temperature, loosen the hips, wake up the calves, and they might even include a few strides so race pace doesn’t feel like a shock. But a new study asks whether a warm-up is also about getting the brain ready.
Researchers tested whether combining cognitive tasks with a standard physical warm-up could improve 1-mile performance in recreational runners. The participants were 25 experienced recreational runners, 11 men and 14 women, with an average 5K personal best of about 23:31 and weekly mileage of around 20 miles/30 kilometers. Each runner completed three separate testing sessions:
One with a physical-only warm-up.
One with a physical warm-up plus low-load cognitive tasks.
One with a physical warm-up plus high-load cognitive tasks.
After each warm-up, they ran four laps of a 400-meter track as fast as possible, with their watch face covered so they had to rely on feel rather than constant pace feedback.
The physical warm-up included a 1200-meter easy jog, 800 meters alternating 100-meter jogs and 100-meter strides, and three minutes of active stretching drills.
In the cognitive warm-up conditions, runners completed four three-minute cognitive tasks before and between the physical warm-up components. These tasks targeted mental functions like switching between tasks, inhibiting responses to stimuli, decision-making, and memory—they were doing short bursts of focused mental work designed to activate the brain without exhausting it.
Compared with the physical-only warm-up, runners were faster after both cognitive-plus-physical warm-ups. The low cognitive-load condition improved 1-mile time by about 8 seconds, or 2.03%, while the high cognitive-load condition improved performance by about 11 seconds, or 2.80%.
Even more interesting, the runners did not appear to be simply muscling their way to faster times.
Their perceived effort was lower after the combined warm-ups, and their average heart rate during the time trial was also lower.
Readiness to perform was higher, meaning runners felt more prepared to run hard.
Cadence and stride length did not meaningfully change, suggesting the performance boost was not explained by obvious mechanical changes.
What this means for runners
The practical takeaway is not that you need to download a cognitive testing app and start doing mental arithmetic before every workout. But this study does suggest that the best warm-up may prepare both the body and the mind.
Before short, hard efforts like mile repeats, 3K/5K races, track sessions, or time trials, it may be useful to add a small cognitive “activation” layer that includes short reaction tasks, quick decision-making drills, coordination games, fast feet with visual cues, or even structured focus routines that force you to engage attention before you start running hard. The important point is dose. A few short mental tasks intermixed with jogging, strides, and drills may help you feel sharper and more ready, but a long, mentally draining task probably does the opposite. For most runners, I’d think of this as sharpening the nervous system rather than “training the brain.” Keep it brief, keep it engaging, and test it in workouts before trying it on race day (as with all things).
