If you are going to run a marathon visit the toilet first

An Olympic marathoner pooped himself and collapsed,here's why marathons wreak havoc on your body

    NBC

Evidence of Diniz's severe gastrointestinal issues — including video of the athlete apparently attempting to soak up leaking fecal matter using a sponge — has surfaced on NBC.

The French Olympic race walker Yohann Diniz was leading Friday's 50K — until he collapsed on the side of the track shortly after apparently defecating mid-walk.

And while Diniz's problems are severe, it's not unusual for athletes to experience gastrointestinal problems while competing in long-distance events.

If your running and have to go , there is no fun to it.

    Here Diniz is holding it in with what apparently  sems like a sponge  NBC

According to the Mayo Clinic, scientists still aren't sure exactly what causes runner's diarrhea, but they have some compelling theories. Some suggest it's a result of the severe physical jostling a marathon can impose on your internal organs. Others think it happens after prolonged periods of decreased blood flow to your intestines.

Among all of these theories, one thing is clear from studies on long-distance athletes: Food simply moves more quickly through your system when you're an athlete training for a strenuous event.

    Ueeek! NBC

Aside from diarrhea, many long-distance runners and race-walkers experience other health issues during or after training, including acid reflux — a condition with effects like heartburn, indigestion, coughing, hoarseness, and asthma.

There's even some evidence to suggest that prolonged, intense exercise — like the kind you'd do in the weeks and months before a marathon and during the race — can negatively affect your immune system by reducing the body's natural ability to fend off upper-respiratory infections including colds and the flu.