Race Season Is Here: Why Long Runs Wreck Your Gut — and What Marathoners Should Know About Hemorrhoids

September 18, 2026

Author: George Edward

If you're training for a fall marathon, this is the hard part. Berlin goes off on September 27, Chicago and New York follow in the next few weeks, and runners everywhere are deep in peak mileage — the 18- and 20-mile long runs that make or break race day.

Nobody posts about what those runs do to your gut. Coaches call it "runner's trots." Gastroenterologists call it exercise-induced GI distress. Either way, if you've ever cut a long run short to sprint for a porta-potty, you know. And what most training plans never mention: the same forces that upset your gut on long runs are the ones that irritate hemorrhoids — right when you can least afford to be miserable in a pair of running shorts.

Why long runs hit the gut so hard

A few things happen on a long run, and they stack. Your body shunts blood away from the digestive tract toward working muscles, so the gut gets less oxygen and gets cranky. Two-plus hours of pounding physically jostles the intestines. Sweat losses lead to dehydration, which irritates the gut further. And race fuel — gels, sports drinks, caffeine — is a concentrated sugar load hitting a stressed digestive system. The result for a lot of runners is urgency, cramping, and loose stools during or right after long efforts.

That's not a fringe complaint. GI distress is one of the most common reasons runners report bad races, and it's the reason experienced marathoners "train the gut" — practicing race-day fueling on training runs so their stomach learns to handle it.

What this has to do with hemorrhoids

Hemorrhoids are swollen veins in and around the rectum, and everyone has the underlying vascular cushions — they become a problem when they're swollen and irritated. A heavy training block can push on them from several directions at once:

  • Repeated diarrhea and urgency. Frequent loose stools mean frequent wiping and constant irritation of the anal area. Diarrhea is a well-known hemorrhoid aggravator, same as constipation.
  • Dehydration on the other end. Runners who under-drink on non-run days often swing the opposite way — hard, dry stools and straining. Straining is the classic driver of flare-ups.
  • Friction and sweat. Two hours of chafing in sweat-soaked shorts leaves the skin around the area raw, which makes any existing hemorrhoid itch and burn more.
  • Race travel. Flying or driving hours to a race means long stretches of sitting — more pressure on the same veins — plus disrupted bathroom routines and unfamiliar food.

To be clear: running itself isn't bad for hemorrhoids. Regular exercise helps keep bowel habits regular, and that's a net win. It's the extremes around a marathon build — the diarrhea, dehydration, and long sitting — that cause trouble.

Getting through peak weeks without a flare-up

Train your fueling, not just your legs

Don't try a new gel, new sports drink, or a bigger caffeine dose on race day. Use your remaining long runs to rehearse exactly what you'll take, and drop anything that reliably sends you to the bathroom. Many runners also learn which foods to avoid the night before a long run — high-fat, high-fiber, and spicy meals right before a hard effort are common triggers.

Drink like it's part of the plan

Hydration does double duty here: it lowers your odds of GI distress during the run and keeps stools soft between runs so you're not straining on the toilet. If your urine is dark by the afternoon, you're behind.

Clean up gently after rough runs

If a long run ends with urgency, the wiping that follows often does more damage than the run. Dry toilet paper on irritated skin scrapes; scrubbing makes it worse. A hygienic cleansing lotion lets you clean the area gently and completely without the sandpaper effect, which matters a lot when you're going several times a day.

Make the sitz bath your recovery tool

Runners ice their knees and foam-roll their quads, then ignore the part of their body that's actually burning. A 10–15 minute warm soak with a sitz bath soak after a long run calms irritated tissue, eases that swollen, pressured feeling, and takes almost no effort — you can do it while you scroll your training log.

Have symptom relief on hand for race week

If a flare-up shows up anyway, you want relief that doesn't require a pharmacy run in a strange city. An advanced hemorrhoid cream with 5% lidocaine and phenylephrine temporarily numbs pain and helps shrink swelling so you can sit, sleep, and get to the start line. For sharp pain that's mostly about sensation — sitting on a plane, the post-race drive home — a max-strength 5% lidocaine numbing cream is the more targeted tool. These relieve symptoms; they don't cure the underlying vein, so use the calm they buy you to fix hydration and bathroom habits.

One thing runners shouldn't shrug off

Rectal bleeding in a runner is usually chalked up to hemorrhoids, and often that's right. But don't self-diagnose bleeding you've never had checked — especially if it's dark, mixed into the stool, or comes with weight loss or a real change in bowel habits. And if a hard race brings on bloody diarrhea, fever, or pain that keeps getting worse, that's a doctor visit, not a cream situation.

Peak weeks are supposed to hurt — in your legs. Handle the gut side deliberately and your backside can make it to the finish line in better shape than your quads.

This article is for informational purposes only and is not medical advice. Talk to your doctor about any persistent symptoms, rectal bleeding, or questions about your health.


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