Holly Widdowfield can laugh now. And she does so freely, while she leans back on a lounge chair in a dim room that can only be described as otherworldly.

The floors, walls and steeple-shaped window frames are all covered in a blizzard of three tons of white Dead Sea salt. The air is filtered outside and cleansed every 45 minutes, kept between 40 and 60 percent humidity and infused with tiny particles of crushed up salt.

It’s the Salt Spa Colorado in Boulder, the only dry aerosol therapy facility in the state and one of fewer than a dozen in the nation.

The premise is simple: Inhale the salt particles, and you’ll breathe better.

Advocates say this nearly century-old therapy is backed by research, Eastern and Western medical principles and an almost innate common sense. we spray saline in our noses and eyes, and we gargle salt water when we have a sore throat. Hospitals use saline drips. And think about how it feels to breathe ocean water. for advocates, a salt spa — even if the room does look like a mystical scene from a C.S. Lewis book — is an obvious and logical treatment.

Still, more traditional medical professionals don’t recommend it, noting there is no credible scientific evidence that it works. Skeptics chalk up anecdotes, like Widdowfield’s, to another point for the placebo effect.

Earlier this year, whenever 65-year-old Widdowfield would laugh, her lungs would crash into an unstoppable coughing fit. It might seem small, but that’s the worst part of having Chronic Obstructive Pulmonary Disease from a lifetime of smoking, says the Boulder County resident.

“I couldn’t laugh,” she says. “And I like to laugh.”

Today is Widdowfield’s 24th visit since April. It took a few sessions for her to start feeling a change in her breathing, but today, she says the air gets so much deeper into her lungs.

She sits in one of eight chairs in one of two salt rooms, across from Mari Anne Kacy, who drives to Boulder’s salt spa twice a week from Fort Collins.

Kacy has suffered with severe asthma for 45 years and tried “every medicine known to mankind,” to no avail, she says. She says she was willing to try anything, and halotherapy made sense to her.

After three sessions, she didn’t feel any noticeable difference. but then she hit rock bottom. She was hospitalized and doctors put her on an oxygen tank 24/7. then, at her next salt spa session, she says something happened.

“I came in here, sat for 15 minutes and shut my oxygen off. I couldn’t believe I could sit here and not use oxygen. Something is working. Something is right,” Kacy says. “Today, I’m oxygen free.”

Nita Desai, the salt spa’s co-owner — who is a western family physician, as well as holistic medical doctor and certified Ayurvedic practitioner — says those kind of results are common.

In fact, she says, one study of halotherapy found that close to 80 percent of patients experienced reduced or no symptoms after 14 to 24 treatments. These people didn’t need any additional therapy for a six-month average.

In other words, Desai says, many people “can do 14 treatments and go six months without another asthma attack.”

How it works

The trick? The salt is slightly negatively charged, and mucus membranes are positively charged. The negative molecules stick to the positive, or the salt affixes to the mucus, drawing out the water and liquefying the mucus, so the body can expel it, according to Allen Tawa, co-owner of the salt spa.

Advocates say salt has an anti-inflammatory effect on mucus, increasing ciliary activity to help liquefy and bring up mucus in your airways. It claims to clear pollens, viruses, pollutants and toxins out of the lungs, sinuses and nasal passageways.

Advocates claim it can help people with asthma, allergies, respiratory irritations and inflammations, bronchitis, cystic fibrosis, chronic cough, sore throat, congestion or a runny nose, snoring, tonsillitis, chronic rhinitis, skin conditions (eczema, psoriasis, acne) and children with ear infections, as well as prevent illnesses, reduce stress and anxiety and regulate sleep patterns.

An added bonus, Tawa says, is the negatively charged atmosphere has a calming effect on the nerves and body (like the salty beach air, but 10 times as concentrated), and it filters out pollens and irritating particles in the air. Some air filters use this “negative ion technology.”

Plus, Tawa says, salt is antibacterial, antiviral and anti-inflammatory.

The real player is the “halogenerator” machine, which grinds salt to one tenths of a micron in size — small enough to penetrate into the lowest depths of the lungs, Tawa says. The salt on the ground and walls only plays a 5 percent role in the treatment, but it helps create that negatively charged environment, he says.

In a sense, Desai says, a salt spa is like you are sitting in a Neti Pot, which flushes out the nasal cavities with saline water.

But she says it won’t affect your blood pressure; after one hour in the salt room, you only consume as much salt as one potato chip.

The idea came from salt caves in Eastern Europe. Salt miners weren’t suffering respiratory and pulmonary problems, and people began investigating the connection between salt and health. this led to “speleotherapy,” or cave therapy. Patients descend into salt caves for several hours daily for several weeks.

Boulder’s center opened about a year and a half ago. but halotherapy has now been used in Eastern Europe and Russia for more than a decade.

In fact, most of its research comes from Eastern Europe. Desai cites more than 200 articles on the topic by the head of the Clinical Research Respiratory Center in St. Petersburg, Russia.

In 2006, the new England Journal of Medicine published an article showing how hypertonic saline (extra-salty, sterile water) had a positive impact on the lung function in cystic fibrosis patients. The patients also had fewer lung infections. The study was funded by the Cystic Fibrosis Foundation.

But still, critics say, there are no clinical studies in the United States.

And the Salt Spa Colorado doesn’t advertise as a “medical treatment.”

National Jewish Health, the nation’s top respiratory hospital, does not recommend salt spas for patients, says William Allstetter, the director of media and external relations.

He says the only published studied he’s aware of are three small ones from “obscure Russian medical journals.”

“We could not possibly ask our patients to inhale a potentially irritating substance based on such meager evidence,” Allstetter says, adding that National Jewish has no plans to study halotherapy or begin offering it in the future.

That isn’t stopping as many as 170 patients who visit the Salt Spa Colorado every week during the winter cold season. And Kacy, the asthma patient, doesn’t plan on cutting back her lengthy drives to sit in the salt chamber. Regular sessions last 45 minutes, and sometimes Kacy spends two to three sessions back-to-back.

She says she’s excited for her upcoming doctor’s visit to see how her lungs have improved and hopefully cut back on medicine.

“I think I will absolutely be able to cut it down. I don’t think I need it at all anymore. like now,” she pauses to take a deep breath and smiles. “I’ll just be sitting here and suddenly take this deep breath and think, whoa, I didn’t know I could breathe that deeply.”