It looks a little like what you do on the beach when you're wearing a swimsuit and someone wants to take your photo, only what seems like sucking in your stomach turns into relatively extreme contortions. Dubbed "alien yoga" on social media because of the otherworldly way your abdomen looks when doing the exercise, it's actually one of the cleansing exercises of classical Hatha yoga, reports Yoga Journal.

The practice claims to help with digestion by massaging the organs through strong rolling movement of the abdominal muscles. It's not commonly taught in Western yoga classes, according to nauli.org, but in some yoga traditions, it was among the first exercises taught to new students.

Practitioners laud what nauli can do for digestion.

Los Angeles yoga instructor Lisa Wolford writes in Yoga Journal, "The Hatha Yoga Pradipika states that nauli stimulates the digestive fire, thereby removing toxins, indigestion, and constipation. It is considered a Shat Karma, which is an internal cleansing to aid with excess phlegm, mucus or fat."

The Gheranda Samhita, one of the three texts of classic Hatha yoga, claims that nauli "destroys all diseases and increases the bodily fire," Wolford says. "In addition, Nauli tones the abdominal muscles and massages the internal organs."

What it's like


The chief ambassador for the Yoga Alliance, Andrew Tanner has taught yoga for 15 years. He practices nauli and teaches his students uddiyana bandha, a preparatory technique for the exercise. It translates to "naval lock" and it's kind of a frozen pose.

"It's like nauli without moving things around," Tanner tells MNN.

To do it, you breathe out all the air in your lungs, then keeping your mouth and nose closed, you draw your innermost abdominal muscles up and in, bringing your organs up under your ribs.

"It looks like all the stuff in your belly, your inner organs, are drawn up under your rib cage," Tanner says. "That's why you have to have no air in your lungs."

The next level of challenges is the ability to relax and contract the muscles in the front of your abdomen.

"Think of it as if you took everything that was behind your abs and pulled them under your ribs, but your muscles are still there and it creates a wavelike appearance," Tanner says.

The feeling is odd, and even a bit frightening the first few times you do it, he says.

"At first, when you're not used to it, it can feel like you're being slightly suffocated. It's not exactly comfortable, especially if you have a lot of toxins in your body and a lot of tensions in your abdomen and chest and throat," Tanner says. "You actually feel like the air is being sucked out of your throat. It can be scary. Once you get used to it, it can feel very pleasurable."

Who should and shouldn't do it

Nauli can be taught to people of any age, says nauli.org, but it's considered a difficult and advanced exercise. Because you can hurt yourself if the exercise isn't done correctly, it's safest if you learn how to do it with a well-versed yoga teacher. It often is recommended only for advanced yoga practitioners.

Tanner says it just depends on your physical health. Some people can't do it because it's too challenging. They're too stressed and can't control their breathing like they need to.

Some experts advise that you shouldn't attempt nauli if you're pregnant or if you have heart disease, high blood pressure, ulcers or other gastrointestinal issues.

"I strongly recommend finding an experienced teacher to learn this 'kriya' — cleansing," says Wolford. "As potent as it can be to cleanse, the powerful vacuum created in the abdominal and pelvic cavities can also lead to disorders."

Helping the body

Gastroenterologist Dr. Partha Nandi, M.D., host of the syndicated medical lifestyle show "Ask Dr. Nandi," is familiar with nauli and can understand why there would be gastrointestinal benefits after doing it.

"You're moving abdominal muscles and you're moving your body and becoming more active and when you're doing that, you're going to help with digestion and constipation issues," he says. "You're moving the part of your body that actually has the organs for digestion and moving the muscles surrounding them."

Just being active is a benefit, Nandi points out, because in general, people who aren't mobile tend to have more constipation issues.

Nandi also cautions that people with GI issues, such as hernias, ulcers and Crohn's disease, as well as cardiovascular issues should avoid the exercise, which could cause more problems. But if you're healthy and learn the exercise slowly with an experienced teacher (not from an Instagram video), the chances of injury are lessened.

While practitioners say nauli "massages the organs," Nandi isn't so sure that's necessary.

"I don’t think there is evidence that massaging the organs makes a huge difference," he says. "I think typically your organs don't need to be massaged."

(As an aside, there is a practice called organ massage or visceral manipulation where a practitioner does deep-tissue massage with the goal of restoring normal organ function.)

If you don't have the abs or the interest for nauli, there are other ways to help with digestive issues, like adding more fruits and vegetables to your diet to get fiber.

"There's this really revolutionary thing called drinking water," Nandi says. "I also believe that probiotics work quite a bit and also prebiotics, and then movement is going to be tremendous for people. If you're someone who doesn’t do much and sits on the couch, you'll be surprised at how much drinking water and moving helps."

Mary Jo DiLonardo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.