Let’s face it: Constipation sucks, even when you’re not training for an epic race of athletic event. But when you’re headed to the starting line, feeling weighed down, lethargic, and cramped isn’t just a bummer, it can directly interfere with your training progress, leading your pace to drag and your endurance to sputter. 

“Constipation may also signal to your brain via the gut-brain axis that there is an imbalance," Kelly Jones MS, RD, CSSD, LDN, says. "This may cause the body to continue to release hormones to the digestive tract rather than to your muscles to support exercise." 

And that means you won’t be at your best. The gut-brain relationship can also impact your stress level, making it harder to zone in and do your thing. 

What’s Behind the Back Up: Why Are You Constipated? 

Any number of things can cause constipation, making it hard to consistently prevent it.

“Constipation can be a symptom of a digestive disorder, or it can be due to low fluid intake, low fiber intake, reduced activity level, too little sleep, changes in schedule due to traveling, high stress, and many medications,” Jones says.

Related: Healthy Snacks for Traveling: How to Curb On-the-Go Munchies

If you’re racing in a new city, arrive as many days early as you can to give your system time to acclimate.

“It’s also helpful to train at the time you’ll be racing, so your body is primed for racing versus digesting at that time of day,” she says. 

Get Your System Rolling Before the Race

If you need to get things moving and have at least a day, generously increase your water intake. Constipation is often due to low fluid intake, keeping food from moving through the digestive tract effectively.

“If your body doesn’t have access to the water it needs, it will pull it from the food waste in your large intestine, which results in harder stools that are difficult to pass,” Sam Presicci, MCN, RD, LD, CPT, Lead Registered Dietitian at Snap Kitchen, says.

Women should aim to take down at least 90 ounces of water daily, and men should shoot for about 120 ounces. And as a general rule, be sure to eat plenty of fibrous foods, like grains, greens, apples, and beans.

Related: 5 Post-Workout Fuel Mistakes You're Probably Making

“Both soluble and insoluble fiber help prevent constipation,” Presicci says. “Soluble fiber helps to make your stool softer, larger, and easier to pass, and insoluble fiber adds bulk, which helps fecal material move through the gut easier.”

But there's a caveat: If you’re not used to eating fiber and suddenly load up, you’ll become more constipated while your body adjusts, so skip this tip. High-magnesium foods like nuts, grains, leafy greens, and seeds also get things moving, as does a magnesium supplement.

“I recommend one that is NSF certified for sport or Informed-Choice certified the night before the race," Jones says. "A bonus is that magnesium also helps some people fall asleep."

And sleep itself makes a difference, too.

“Rest helps stress hormones stay in balance, which can impact digestive function,” Jones says.

Aim for 7-8 hours of sleep the whole week before the race.

What to Do if You're Constipated

The morning of a race or competition, you can’t beat adequate fluid intake, a healthy breakfast, and — if it’s your usual habit, a nice big cup of coffee — which has laxative abilities. Finally, grab an apple on your way out the door.

Related: Avoid These 5 Race-Day Breakfast Mistakes to Finish Strong and Fast

“Apples offer fiber, but they also contain pectin, which is fermented by bacteria in the gut to form short chain fatty acids that bring water into the colon, soften stool and decrease transit time,” Presicci says.