At times, it can sound like snake oil, only there’s no oil, pills, syrup or powder.

Claims for “inversions” — purposely going upside down for a minute or more to reverse the pull of gravity on the body — can sound like a cure-all and include relieving back pain, depression and arthritis aches, improving muscle strength and heart health, stimulating immune strength and even creativity.

With the rise in the popularity of yoga in the past decade, the subject of inversions, both its benefits and risks, likewise is starting to work its way into the mainstream.

Yoga postures include handstands, headstands and shoulder stands, or suspending from a cloth hung from the ceiling in aerial yoga. Other inversion options include inversion tables and gravity boots, made famous by Richard Gere in the movie “American Gigolo” in 1980.

Lack of studies

Yet studies providing scientific evidence of the benefits of inversions haven’t caught up with the growth of yoga, which has grown from 4 million Americans practicing in 2001 to 22 million in 2011, according to the latest data from the Sporting Goods Manufacturers Association.

Locally, more than 20 yoga studios have opened in the Charleston area in the past decade. That growth does not include gyms and recreation centers offering yoga.

Yoga’s popularity has grown faster than the research providing evidence for its effects, particularly with inversions, on practitioners.

A small-scale Swedish study, published in February and filed in the National Institutes of Health library, on the effects of inversions on “heart rate variability” and blood pressure noted the lack of evidence. “Yoga exercises are known to decrease stress and restore autonomic balance. Yet knowledge about the physiological effects of inversion postures is limited.”

The study found an improvement in heart rate variability, a sign of a healthy heart, and subsequent “restorative effect on the automatic nervous system,” but not on blood pressure (likely due to participants already having healthy blood pressure levels).

Benefits and risks

Several local physicians who were asked to be interviewed on the subject of inversions declined, citing a lack of knowledge about it.

Orthopedic surgeon Dr. Michael Wildstein of The Wildstein Center, says that overall the benefits of yoga and inversions, when done properly, outweigh the risks.

“There was a decent study last year or two that compared yoga instructors’ MRI scans with regular people’s MRIs, and it found the yogis to have fewer degenerative changes overall compared to the normal population,” says Wildstein.

Still, Wildstein noted the lack of study, other than risks for glaucoma patients, on the benefits of inversion poses for sufferers of back and neck pain.

One posture gives him pause. “Shoulder stands could in theory exacerbate upper extremity symptoms of a herniated disc in their neck, although there are no case studies and I have never seen this,” says Wildstein.

“I personally recommend for people with long-standing neck issues, or serious nerve impingement, that come to see me in my practice to avoid axial loading of their necks with ‘sirsasana’ (supported headstand) and similar poses, as this tends to worsen their pain just as running on an arthritic knee worsens pain, but that’s fairly common sense, I guess.”

As for inversion tables, Wildstein says using them are “great for lower back pain and even, sometimes, sciatic pain.”

Physical therapist and certified personal trainer Sarah Ellis says while she likes passive inversion tables for spine health, she has some reservations about two yoga inversion poses: headstands and shoulder stands.

“I’ve found few people in the general exercise public that have strong enough scapula (shoulder blade) strength to do a headstand correctly, which can then be counterintuitive if you are compressing the cervical spine instead of lengthening it,” says Ellis, a former collegiate pole vaulter and avid kiteboarder.

“Mechanically, it seems that there is no way a shoulder stand could possibly be good for the neck.”

The up side

Cortney Ostrosky, a certified yoga instructor at Jivamukti Yoga Charleston and Charleston Power Yoga, offers two or three “inversion workshops” every year, in part because she loves the challenges and benefits of poses.

She says those benefits not only include “decompressing your joints” and “flushing metabolic wastes” out of feet and legs,” but for her, being able to control your mind and body when “your world is flipped upside down.”

“Getting into my yoga practice, the inversion aspect of the practice resonated with me because it was a challenge. It takes on the perfect balance of hard work and playfulness, of holding on and also letting go, and of strength but also flexibility,” says the 29-year-old.

“It also helps you get over the fear factors of falling down and looking silly. You can let go of your ego. For many people, it’s the most intimidating thing about yoga. It’s completely disorienting. Up is down. The pull of gravity is different on your body.”

She adds, too, that while doing a handstand, headstand and other inverted poses takes skill and practice, even beginners can benefit from inversions either by using a wall to balance against or just propping their legs up against the wall.

For those with risk factors such as neck impingement or high blood pressure, she says inversions can be modified to avoid problems.

“That’s why I’m adamant about explaining how to do the postures correctly so that you’re not impinging on the neck. If you’re in perfect alignment, there shouldn’t be impingement on the neck. In a headstand, for example, your head should be touching minimally,” says Ostrosky.

Ideally, she adds, beginners or those who wanted to advance their inversion practice would take one-on-one sessions with her or other qualified yoga instructor.

No-impact version

Aerial yoga offers the ability to go upside down without touching the ground by hanging off large cloths suspended from the ceiling.

Jordan Anderson of Aerial Yoga and Aerial Silks in North Charleston considers inversions to be healing because it’s “so much fun and so empowering.” She said some people she’s instructed have been helped with anxiety issues.

“Inversions bring out our childlike nature and allow us to see the world from a different perspective. The feeling of being upside-down, as an adult, is truly freeing. It has been shown that laughter and smiling have health benefits, and inversions are great for that same reason.”

Still, Anderson said they are not for everyone. Moderation is the key.

“Anything overdone can be damaging, and even in aerial yoga, we invert in moderation. I see no reason to stay upside down for any extended length of time, but going upside down a little bit each day or week can have great benefits.”