Five things that happen to your body when you run a marathon

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With the first ever Stirling marathon less than 24 hours away, we here at Brig want to not only wish all participants the best of luck, but also offer insight on what happens to the body during this 26-mile event.

But as I’ve never completed a full marathon (I have done a half though, if that makes you feel any better) nor studied the inner workings of the body, this insight was kindly provided by one of our resident sport science experts, Dr. Angus Hunter, a much more qualified source.

Dr Angus Hunter
Dr. Angus Hunter. Photo credit: University of Stirling

Dr. Hunter’s top five tips (complete with lesser qualified interjections):

1. You burn a day’s worth of calories

“Runners can expect to burn a day’s calories in the process of a marathon. This means your body rapidly depletes its fuel stores which, if not replenished, can cause premature fatigue. Anyone training for a marathon needs 40 to 60 additional grams of carbs per hour of exercise to help their performance: that’s why it’s so important to plan your nutrition in the run-up to the event.”

2. Your muscles work incredibly hard

“Evidence suggests that the quadriceps and calf muscles are worked the hardest during a marathon. Our bodies cope with the hard work through appropriate pacing – gained through experience – and adequate hydration to meet the body’s requirements. Keeping on top of this will help your legs propel you around the course.”

Lesser qualified side note: While hydration is key, just keep in mind that the bathroom opportunities often prove incredibly inconvenient and that the person before you quite literally ran in and out of there, probably hoping never to look back on the disaster that is non-flushable toilets.

3. Your pH drops

“Over a marathon, your pH will generally drop throughout – but if you start off fast, you build up acidity, and that will impair the electrical signals that run from your brain across to your muscles. So pace yourself – if you start off slow, you end up clearing more lactate than you can produce, and you won’t get an acidic build up.”

Lesser qualified side note: From personal experience, ‘pace yourself’ is the most important thought to keep with you during the race. It can be incredibly tempting to let all your hard work and training metaphorically fly out the window and instead get caught up in the excitement and hype of more than 6,000 other runners, as well as cheering spectators and music. But this is your race, your body, and your own time. I personally would rather have a slower start than a dead finish. Let the energy carry you rather than rush you, and enjoy the moment. You all have every reason to be proud of this major accomplishment.

4. You might ‘hit a wall’

“The theory is that the point where glycogen (carbohydrate) stores become depleted feels like ‘hitting a wall’. It’s something 40% competitors suffer from but can be avoided with appropriate training.”

5. It takes time to recover

“Your body can take as long as two or three months to fully recover from running a marathon, depending on the intensity you sustained on the run. One theory behind this is that your muscles have suffered low-frequency fatigue, which impairs the release of calcium – and you need calcium for your muscles to shorten – so be aware this will take a couple of months to normalize.”

Lesser qualified side note: While two or three months for a full recovery may sound like a long time, think of all the times you’ll be able to use it as a viable excuse!
“Sorry, I can’t make it – I’m recovering from my marathon.”
“Wasn’t that like two months ago?”

It’s evident that a marathon will take its toll on your body, so please look after yourselves as well as others out there, and remember to embrace the day you’ve been working so hard for!

Also, take some selfies, it’s good for the soul (as well as proving to people that you were actually there).

Liz McColgan joined University students on campus to try out the marathon route
Photo credit: University of Stirling




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