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That pre-race poop will help you run fast and smarter, new research says

Your morning trip to the bathroom even more important than you think

porta potty

For many of us, that pre-race dash to the washroom is essential to our race plan. But does your bathroom trip also improve your cognitive function during your race? In a recent study published in the journal Sports Medicine and Health Science, researchers at the University of Taipei discovered that having a bowel movement before a race helped participants make significantly better, faster decisions on the course. Here’s what you need to know.

stomach pain GI distress

The study

“Constipation is correlated with diminished cognitive function, revealing a possible rectum-brain connection,” the researchers explain. Their study had 13 elite athletes taking part in a Stroop test to assess their cognitive function and executive control. (The Stroop test is a cognitive challenge based on the phenomenon that it is difficult to name the ink colour of a colour word if there is a mismatch between ink colour and the word for that colour—try one yourself, here. The Stroop test was conducted by all athletes under three conditions: not defecating, defecating with a magnesium oxide supplement and defecating without the supplement, with a week between tests.

The theory researchers were exploring is that the brain requires an intense amount of blood flow to sustain high-intensity exercise, something that constipation inhibits.

Chia-Hua Kuo, one of the study authors and an exercise physiologist with the University of Taipei in China, explains in Triathlete magazine. “When you do exercise, especially long-distance exercise, your brain is going to be sending high amounts of commands to the muscles,” Kuo says. “Whether or not you can sustain muscle contraction is not really depending on whether your muscle has wrung out the energy, it’s whether your brain is able to challenge your muscle.”

woman running on bridge

An impressive improvement

A remarkable 100 per cent of the athletes improved their Stroop test scores after taking magnesium oxide and defecating, while 69 per cent (9 out of 13) showed improvement after defecating without the supplement. Interestingly, full-body PET (a type of imaging test) scans showed that the butt region was just as active as the brain during the Stroop test—take a look here.

What does this mean?

While there’s clearly more research to be done, the study suggests an intriguing, previously unexplored link between rectal state and cognitive performance. The researchers propose that magnesium supplementation to aid rectal emptying could be a novel strategy for optimizing cognitive function in athletes. For us regular folk—try to schedule that poop pre-race—ideally, 60-90 minutes before you toe the line.

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