Kristen Bell Wears a Bikini and Mittens to Try Cryotherapy: 'I'm Only Here for the Health Benefits'

Cryotherapy is one of those things you've probably heard about but are fuzzy on the details. Luckily Kristen Bell is here to walk you through the process.

Bell, 40, shared a series of videos on her Instagram Stories of herself going through a cryotherapy treatment, noting that she was "trying out" the therapy at a California wellness center. In the videos, Bell wears a purple bikini, high socks, thick mittens, an ear warmer, and a face mask.

Her husband Dax Shepard talks to her behind the scenes, asking how she feels before she gets into a cryotherapy chamber. "Good. I can do it," she responds, as Shepard says she looks "like a Bond villain girl" in her outfit.

Bell then gets into the chamber, noting that it's -169 degrees inside. In the next scene, the door of the chamber opens, and you can see Bell dancing inside under the words, "I'm only here for the health benefits."

"I think I'm ready to graduate to intermediate," she says, as she steps out.

Bell didn't offer up any more details, but it seems like she enjoyed the process.

OK, but what is cryotherapy?

Whole body cryotherapy, usually just referred to as "cryotherapy," is a treatment that involves getting into a chamber and exposing your body to air that has been chilled by liquid nitrogen. Temperatures inside the chamber can get between -160 and -300 degrees. Proponents claim that whole-body cryotherapy can reduce inflammation, speed recovery from workouts, burn hundreds of calories, improve the appearance of cellulite, and even help with stress and anxiety. (Bell didn't specify why she decided to do cryotherapy.)

How does cryotherapy work?

The process is pretty simple from a patient standpoint. You put on gloves, shoes, socks, and a protective headband to cover your ears, and wear little else, according to Harvard Medical School. You then step into a cold chamber for three to four minutes.

The idea behind it is tied to the observation that applying ice or other cold treatments can give you pain relief when you have injured or overused muscles, Harvard Medical School says.

Why is cryotherapy controversial?

Despite many claims by spas and wellness centers that cryotherapy will do a slew of different things for your health, "there's really no evidence to suggest that it's useful, at least in terms of musculoskeletal injuries," Jason Womack, MD, chief of the Division of Sports Medicine at Rutgers Robert Wood Johnson Medical School, tells Health.

In fact, the Food and Drug Administration specifically says online that it "does not have evidence" that whole body cryotherapy effectively treats disease or conditions, including chronic pain, rheumatoid arthritis, stress, and anxiety. The FDA also says that there is "little evidence" that cryotherapy can improve blood circulation, increase metabolism, improve recovery and soreness after workouts, and relieve joint and body pain.

The FDA points this out, too: "Not a single whole body cryotherapy device has been cleared or approved by the agency in support of these claims."

Dr. Womack says his medical center isn't using whole body cryotherapy devices, adding, "it seems to be more of a holistic approach as opposed to a specific treatment for an injury."

Whole body cryotherapy is generally considered safe, according to Harvard Medical School, which noted that "few problems have been reported with its use." However, if you have an underlying health condition like high blood pressure, heart or lung disease, poor circulation, allergy symptoms triggered by cold, or nerve disease in your legs or feet, it's probably best to take a pass, or at least talk to your doctor about it.