A brain running with a backpack
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Fitness Training

This is what happens to your brain when you go running

One neuroscientist reveals nine ways in which pounding the pavement affects your mind and body.
Written by Tom Ward
4 min readPublished on
Just what happens inside your mind when you go for your 5K park run, or jog to and from the office?
We recentlyspoke to neuroscientist Ben Martynoga about the science of lacing up and heading outdoors.

1. A runner’s high is a real thing

“It’s natural to feel fatigued during a run, but if you keep going, you may feel your reward pathways, like endorphins and endocannabinoids, kicking in,” says Ben. “The body makes its own drugs in a sense. Endorphins are like opiates; endocannabinoids act on similar targets in the brain that cannabis does. This isn’t to say it’s physically addictive, but it may account for the elusive ‘runner’s high’ which makes the experience pleasurable."

2. Your brain shrinks on a long run

“Studies found that ultra-marathon runners’ brains can shrink by up to 6% following a run. Although the brain cells do come back over the following months,” Ben explains. “It seems intuitive that an exhausting run will exhaust your brain. Your brain is a small organ, but it uses 20% of the body’s calories. Putting your body through serious physical trials is likely to have some cognitive pay-back.”

3. Stress isn’t just in the mind

“If you’re having a stressful day at work, it takes effect on your body. The hypothalamus in the base of the brain sends a signal to your pituitary gland and together they signal the adrenal glands, above the kidney,” Ben explains. “As a result, your body courses with adrenaline and cortisol. Your heart rate goes up, your pupils dilate, your blood pressure and breathing rate increases. This won’t help you with the presentation you have to write. But, if you can recognise this state, you can choose to do something more productive, like going for a run.”

4. You were born to run

“If you look at our evolution it’s clear that your body wants to run,” Ben says. “And it’s a great way to regain control of your mental faculties. There’s very clear evidence that running boosts your executive function – your ability to direct your attention to what you want to do, and to shut out distractions, and solve problems. It also boosts your working memory, so a good run will actually help with that presentation.”

5. Running increases mindfulness

“Running can help induce a meditative state, a feeling of being in the moment. You focus on your breathing, your footfall, your surroundings,” says Ben. “If you’re lucky you’ll enter a kind of flow state where you’re not worried about what happened yesterday, or what’s going to happen tomorrow. You’ll arrive home unburdened by the problems of the day.”

6. The brain creates chemicals to help fight post-run inflammation

“These drug-like chemicals can give you a sense of euphoria that might carry you through to the end,” Ben explains. “People talk about how they forget the hell of a long run and just remember the positives afterwards, and this could be why. Psychologically, we give more weight to positive memories – such as a sense of achievement – than the negative. In some cases these chemicals can also help you fight through the pain of inflammation post-run.”

7. Running can increase your memory

“Some of these affects – including boosting attention and memory – last after you’ve stopped running,” says Ben. “Your body winds down after a run, but we think these effects are cumulative. The best studies are in children and older people. There’s evidence that building up exercise over months can increase the size of the hippocampus, and that goes along with improvements in certain types of memory function.”

8. The lazier your body, the lazier your brain

“Sitting around all day is dangerous,” says Ben. “It’s not just bad for your body, it’s bad for your mental state. Your ability to deal with the world. It doesn’t have to be extreme, but getting active will benefit us, and there’s very little cost to it.”

9. But the first step is the hardest...

“Starting is the hardest bit," Ben reveals. “Part of that is making the decision to commit to taking the initial step, and deciding to shut out demands on your time." This leads to a mini conflict in your brain, but, Ben adds, if you do block out your inner stick-in-the-mud, "you won’t regret it.”