There’s something uniquely wild about pushing your body 26.2 miles on foot. It’s part physical test, part mental endurance, and part raw stubbornness.
For anyone who’s crossed that finish line—salt-streaked, legs cramping, maybe even crying a little—there’s no doubt the marathon takes its toll.
But what’s going on upstairs during all this? More importantly, does running a marathon actually change your brain, and if so, does it last?
Let’s break it down. You don’t need a neuroscience degree to make sense of what marathon running can do to your brain. But the truth is, the effects are both fascinating and a little surprising.
Key Brain Effects Post-Marathon
Metric
Details
MWF Drop (Pontine Crossing)
Up to 28% after marathon
MWF Drop (Corticospinal Tract)
Up to 26% after marathon
Partial Recovery Time
2 weeks post-race
Full Recovery Time
2 months post-race
EEG Changes
Reduced alpha/delta waves 1–6 days post
EEG Recovery
All normalized by 13–15 weeks
Memory Effects
Explicit memory briefly reduced
Long-Term Cognitive Harm
None reported in healthy individuals
What Happens During a Marathon?
Most marathon runners know the bonk. That point—usually around mile 20—when your body says, “Nope. We’re done.” Glycogen stores are gone. You’re scraping the barrel. And your brain? It’s in survival mode.
During a marathon, the brain burns through a staggering amount of energy. It uses up to 20% of the body’s total fuel—mostly glucose.
Once that’s gone, it starts looking elsewhere. And recent research suggests the brain may turn to one of its own key building blocks for backup energy: myelin.
Myelin – The Brain’s Insulation, and Emergency Fuel?
A 2025 study published in Nature Metabolism turned heads by showing that marathon running may temporarily strip myelin from certain white matter areas of the brain. Myelin’s job is simple but vital—it wraps around nerve fibers like insulation on a wire, helping messages travel faster and more efficiently.
Here’s what the study found:
The takeaway? When pushed into extreme stress, the brain might actually consume parts of its own insulation to keep running. It’s a wild adaptive trick—but one that’s reversible.
So, Does the Brain Bounce Back?
Yes, and pretty quickly, too.
That same Nature Metabolism study tracked six runners in the weeks after the race. Two weeks post-marathon, myelin levels were already ticking back up. By two months, every runner’s MWF levels had fully returned to baseline. No damage, no lingering deficits.
This kind of recovery speaks volumes about how resilient the brain really is. Even after an event as punishing as a marathon, it knows how to heal.
What EEG Tells Us
MRI tells us about structure, but what about brain activity? That’s where EEG comes in.
A separate study published in 2025 looked at 30 runners (average age: 45) and tracked their electrocortical activity across four checkpoints: weeks before the marathon, just days before, shortly after, and months later.
Key observations:
What’s causing that temporary disruption? It could be hormones, inflammation, or plain-old exhaustion. But either way, it passes.
You might counter fatigue with proven mindfulness practices that improve focus, helping clear the post-race brain fog.
Memory Takes a Hit (But Just Briefly)
Back in 2013, a small study out of Colby College suggested something interesting: explicit memory, like recalling facts or events, can dip right after a marathon. The likely culprit is the hippocampus, which handles memory formation and is incredibly sensitive to energy deficits.
At the same time, implicit memory (skills you don’t have to consciously think about, like muscle memory or riding a bike) may actually sharpen. It’s probably a stress response. Your brain is conserving resources where it can afford to and doubling down where survival instincts live.
None of this is permanent. Give it a few days, and most runners are back to remembering phone numbers and grocery lists just fine.
What About Long-Term Harm?
Here’s the good news: there’s no evidence that marathons do any lasting damage to a healthy brain.
Researchers in both the Nature Metabolism and EEG studies were clear—any observed changes were temporary. No one suffered permanent cognitive loss, even with measurable short-term impacts.
That said, one caveat came up. The corticospinal tract (one of the most impacted brain areas) is also vulnerable in people with ALS (amyotrophic lateral sclerosis).
While no direct link has been proven between marathoning and neurological risk, it’s worth keeping in mind if you have a family history or underlying conditions. As always, personalized medical advice matters.
Running and Brain Health Over Time
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Let’s zoom out for a second. Marathon running might have some temporary effects, sure. But there’s a bigger story here—about the long-term cognitive perks of running.
Marathon training usually involves months of structured, consistent aerobic work—so you’re not just running 26.2 miles once.
You’re putting in hours of mileage, week after week. All of that contributes to a brain that’s more resilient, more plastic, and more prepared to adapt.
Even the CDC backs this up. They note that preserving myelin through regular physical activity might help protect against neurological decline later in life. So while one race might dip your myelin levels briefly, the big picture is still very much in your favor.
Mood Boosts and Mental Clarity
The “runner’s high” is real—and it’s not just endorphins. When you run, your brain releases a cocktail of feel-good neurochemicals:
All of these are beneficial beyond the finish line. Long-term runners often report better sleep, sharper thinking, and improved emotional resilience—all linked to consistent exposure to these neurochemicals.
And when you’re training for a marathon, that exposure is frequent.
Not Everyone Responds the Same Way
@dw.science Is running a marathon healthy? A group of researchers and frequent runners scanned their brains before and after running a marathon. Surprisingly the levels of white matter in the brain were significantly lower after the race. This suggests that the body uses the fatty substance as fuel to hit the finish line. So why does this matter? The white matter of the brain mainly consists of myelin, which coats the neurons and acts like an insulator. This helps to speed up the communication between the neurons. Without this insulation a pain signal takes much longer to reach its destination. And this is affecting the sensory and motor control of the body. But the good news is, the used-up myelin will be quickly replenished. And to regularly trigger this repair process could have a positive long-term effect for brain and body health. Author: Julia Lazarus #STEMTok #sciencetok #science #learnontiktok #dwscience #dwhealth #strava ♬ Originalton – DW Science
It’s worth noting that research still has limits. Many of the studies focus on healthy, middle-aged runners, most of them male.
That leaves gaps in our understanding of how women, older adults, or people with different fitness backgrounds might respond.
Here’s where we could use more research:
So if you’re someone who’s run 30 marathons, or you’re 65 and gearing up for your first one, there’s still a lot the science world hasn’t answered yet.
Summary
If you’re a healthy adult, you’ve got nothing to fear. Your brain might take a small hit right after the race—think of it as a fog or a “cognitive cooldown.” But it recovers fast, and in the long run, marathon training supports cognitive strength and emotional well-being.
The brain is incredibly adaptable. It knows how to protect itself. And when you train smart—fueling properly, recovering well, and listening to your body, you’re helping it do just that.
