I adjust into my submarine-esque chamber, ready but largely unsure of what to expect. Aside from a thorough briefing from the person monitoring my "dive," I've never even heard of this contraption, much less experienced it firsthand.

I settle onto the comfy blankets and pillows as we begin to "descend"—and I embark on my first foray into hyperbaric oxygen therapy with Oakland's Holistic Hyperbarics.

Once largely relegated to patients recovering from surgery and only when recommended by their doctors (and approved by insurance), hyperbaric oxygen therapy (commonly referred to as HBOT) is becoming more accessible to the masses thanks to Holistic Hyperbarics founder Alex Williams, who discovered the benefits firsthand when recovering from a torn shoulder.

"I went to my doctor, and my doctor said, 'This is going to take six to nine months to heal and here's a prescription for Vicodin,' and I was like, 'There's got to be a different way,'" she says. "I did a ton of research and emptied my savings and bought [a soft-shell hyperbaric chamber]. I started using it and my shoulder was fine after six weeks. I was like 'Okay, I'm sold.'"

Williams shared her experience over Facebook and, before she knew it, friends, friends of friends, and even straight-up strangers were stopping into her home to experience the healing effects of her chamber. Realizing the potential, Williams partnered with doctors, generous friends (who each kicked in thousands of dollars as founders), and investors to raise the money needed to open her spa-like space in Oakland, where lush green plants mingle with three hard-shell hyperbaric chambers.

As for the actual therapy? The experience mimics a dive into water or taking off in a plane, with my ears popping as the pressure and depth change. (I chomp on the provided gum to help relieve the ear pressure.) Once I'm at the designated depth of roughly 16 feet after around seven minutes, Williams—who monitors my dive—instructs me to put on the supplied oxygen mask via our walkie-talkies. Even though there's plenty of oxygen in the chamber, the mask delivers 100-percent pure oxygen, or "pure cellular energy," as Williams puts it. The chamber, with light filtering through the windows, feels largely like sitting in an enclosed room at the regular depth, plus a little more white noise in the background—making it a prime place for snoozeville.

People often find themselves drifting off, although others opt to scroll on their phones or zone out to Netflix for the 75 minutes at the prescribed depth. I settle into one of the best naps of my life, gently awakened by Williams over our walkie-talkie when it's time to end my journey. Returning to normal depth feels similar to the descent, with the same ear popping, but Williams is extra careful to help me out of the chamber, as all that pure oxygen can produce a euphoric effect.

And to be fair, I feel pretty damn great getting out. I plop down in the relaxation area where there is a selection of comfy recliners and massage chairs; gulp down the provided vitamin C and E with my spa water; and gradually return to normal before getting behind the wheel and driving home. Appointments are staggered every 30 minutes, so I seldom felt like there was anyone else at Holistic Hyperbarics aside from myself and the staff, increasing the Zen-like feel.

"I think if we can actually create an environment where people feel really comfortable, we probably have a better shot at healing them," says Williams. "What's cool is that we kind of have this Disneyland moment with them where we're like, 'This is exactly what you want it to be.'"

Originally created to treat the bends, or decompression sickness, the chamber's benefits extend well beyond the spa-like atmosphere and expediting recovery from surgery. At Holistic Hyperbarics, Williams claims she and her staff have helped more than eight women with fertility issues conceive, allegedly by increasing circulation in the uterus. Previously wheelchair-bound patients suffering from Lyme disease are said to have dedicated themselves to multiple-times-per-week hyperbaric treatments and transformed into long-distance runners. And everyone from pro athletes (Raiders and Warriors players are among clients) to those suffering from migraines or concussions have found relief and/or healing following their time in the hyperbaric chamber.

In an effort to make these benefits accessible to the masses, Holistic Hyperbarics offers treatments at a more affordable rate of $250 (compared to $350 at other HBOT centers), with discounted packages bringing the cost down to roughly $170/session. In addition to reducing the high cost of recovery practices—often prohibitive to amateur athletes, as well as the general public—Williams aims to provide the healing of hyperbaric chambers in an atmosphere that more closely resembles a spa than a sterile medical clinic. You can apply for and get an approved prescription for using the chamber via email, with licensed doctors reviewing and approving prescriptions (barring any red flags) within a few hours. And Williams spends a large amount of time fielding questions—like, can you leave your head outside the chamber (no) and does the treatment involve water (also no)—over the phone, but she views it as another way Holistic Hyperbarics differs from other HBOT centers.

"It's another answer to healing that has not been readily accessible" says Williams...until now. "And I'm forcing everyone to be as obsessed with my plan as I am."

// Holistic Hyperbarics, 5764 Lowell Ste. 8, Oakland, hh-bayarea.com