If you’ve ever noticed that constipation feels worse when you haven’t been drinking enough fluids, that’s not a coincidence.
But when you’re dehydrated, your colon shifts into conservation mode, pulling even more water from stool as it passes through, according to Rabia de Latour, MD, a therapeutic endoscopist and gastroenterologist who is an assistant professor of medicine at NYU Grossman School of Medicine in New York City and an Everyday Health medical reviewer.
“It’s the water regulator in your body. When you’re dehydrated — because you ran a marathon or you exercised and didn’t drink enough water — one of the first things it will do is try to steal some water back from stool,” Dr. de Latour says. “So if somebody’s severely dehydrated and the colon absorbs a lot of water, [stool] can become dry and hard like rabbit pellets.”
“Staying hydrated is so important to have easy bowel movements because it helps to keep things moving,” says Amanda Sauceda, RD, a registered dietitian in Long Beach, California, focused on gut health. “If you’re always dehydrated, that will show up with harder stools or you’ll find yourself pooping less often,” she says.