Now, everyone’s gut is different, but as someone who has struggled with her stomach, my guess is that you’re open to anything that will get you closer to an answer (especially an expert opinion). So take your sneakers off and stay awhile—this news may or may not unsettle you. The jury is (somewhat) out—mainly because there are so many types of exercise and levels of intensity that there’s no way to say that all exercise will or won’t cause constipation. It also depends on the person. But most experts agree that consistently doing this one type of workout can cause tummy troubles. That workout, my friends, is our beloved HIIT. But as you know if you’ve ever done a HIIT workout, it can be very, very intense. And if you do something so intense for so long (and so often), it’s not surprising that there’s a catch. Robin Berzin, M.D., an mbg Collective member and Functional Nutrition Program instructor, has seen many patients who consistently do HIIT workouts suffer from digestive troubles. How we move, she says, is important (and often overlooked). “One patient of mine was doing high-intensity interval training almost every day, and it was actually overly stressing her body,” Berzin says. “What we know is that for the gut to move, it has to relax. And when you’re in a state of stress all day, and then you do high-intensity interval training over and over again, sometimes it never gives the gut that time to relax, digest, and move.” In other words, HIIT is tough on the body, which can be great for strength and performance, but not so ideal for digestion. If you’re doing HIIT now and experience no symptoms, that’s awesome and you should keep doing what works. But if you’re a HIIT lover struggling with constipation, it may be time to make some changes. “Incorporate more restorative exercise, more pilates, more yoga, and more walking,” Berzin suggests. “We also advised her to stop doing HIIT workouts so close to when she was eating—this would give her digestive system a chance to do its job well.” Now to be clear: We’re not advising that you stop doing HIIT altogether, forever and ever. After all, HIIT has numerous benefits, and we’re not one to tell you to ditch your workout or sacrifice stress relief. What we are saying is that constipation is a real condition with unpleasant, often painful, side effects—so why not throw a few yoga classes or weekend walks into your mix and see how you feel? At the very least, you’ll be less stressed, which, when it comes to digestion, can actually only help.