A bright screen counts down from two minutes and 40 seconds. Then a second number drops more rapidly: -97, -100, finally slowing near -240 degrees Fahrenheit. I tried cryotherapy to see why celebrities and athletes alike stand in an icy chamber for the sake of health and beauty.
What is Cryotherapy?
Cryotherapy is the trend of fully immersing yourself into a chamber of subzero temperatures, from 238 to 274 degrees Fahrenheit below zero, for up to three minutes. Athletes and celebrities—including Jessica Alba, Daniel Craig, Alicia Keys, and Cristiano Ronaldo—have reportedly benefited from the practice. Reported advantages include softer and younger-looking skin, muscle recovery, and even weight loss.
The therapeutic properties of ice and cold for health have been acknowledged for a long time, with reports dating back to the 17th century. However, as is often the case with Hollywood trends, research isn’t nearly so adamant about the promises of full-body subzero immersion. At any rate, here are a few of the advantages that proponents of cryotherapy report.
Great Earth Sports Performance (GESP), a facility in Los Angeles, describes that during a session of cryotherapy, “the outer skin is briefly frozen, activating increased production of collagen in deeper layers of the skin. The skin regains elasticity and becomes smoother and even-toned, significantly improving conditions such as cellulite and skin aging.”
When it comes to muscle injury or inflammation, RICE (Rest, Ice, Compression, and Elevation) is a well-respected recovery method. Sports-medicine researchers at Vanderbilt University studied the healing properties of ice on twisted knees, stating: “not only does ice cool the superficial aspect of the joint, we now know that the ice actually cools the knee internally.”  However, whereas studies acknowledge the analgesic (pain relieving) affect of cold exposure, less is known about the physical recovery of muscles with exposure.
Mood and Stress
Hydrotherapy (aka water therapy) offers how “applying water of different temperatures to our skin can change our physiology and mood.” According to naturopath Dr. Peter Bongiorno, ND, some studies have found water bathing was linked to decreases in the stress hormone cortisol while balancing the “happy chemical” serotonin, particularly when it comes to cold. 
GESP states that cryotherapy can improve the function of the immune system and decrease stress levels. The release of endorphins is a “survival reaction” to the subzero temperatures. It can benefit mood along with analgesic and anti-inflammatory properties of the big chill.
In 2008, Ray Cronise championed the idea that cold can actually spur weight loss. He came to this conclusion upon learning that Michael Phelps consumed 12,000 calories a day while training for the Olympics. Cronise set out on a weight-loss journey consisting of cool showers, light clothing, and three-mile “shiver walks” in 30-degree weather. In six weeks, he shed 27 pounds with no reported changes to his caloric intake. After Cronise documented his experience with the help of Tim Ferriss, Hollywood’s newest weight-loss trend took off. “Thermal dieting” and 20-minute ice baths became widespread in celebrity circles.  (If you’re interested in other weight-loss tactics, we put together an infographic showing 45 habits linked to having a smaller waist!)
When it comes to cryotherapy, GESP reports that the extreme-cold exposure causes the body to turn up its metabolic rate in order to produce heat. It lasts for five to eight hours and burns 500 to 800 calories in the period following the three-minute session.
My 3 Minutes at Subzero
To test this growing fascination with extreme cold therapy, I visited LA’s Great Earth Sports Performances. The three-minute, full-body session is meant to “decrease inflammation, increase cellular survival, decrease pain and spasms, and promote overall health.”
To start, I walked into a small room where energizing music instantly got my heart racing. (However, this spike might also have been due to the imposing tank already frosting in the corner.)
Then the performance specialist took my blood pressure. I received pair of cozy socks, gloves, and big fluffy slippers—the only articles of clothing I’d wear inside the tank.
I was relieved to see the temperature inside the tank began at a mere (mere!) -98 degrees rather than starting at -200. Over the course of two-and-a-half minutes, it dropped gradually so my body had time—albeit not much—to get accustomed to it.
The tank was cold upon stepping in, but my endorphins were kicking. As an icy fog rose around me, I distracted myself by peppering the performance specialist, who stays in the room for the full session, with questions about the process and how the proposed benefits could be true.
Nearing -240 degrees with 30 seconds remaining, a numbing pain began to set in. But just as quickly, the fog disappeared and the session ended.
Immediately after, I was buzzing with adrenaline. The greater HUM office can vouch for my high energy levels for the remainder of the day. In terms of recovery, I had twisted my knee the previous week. It became sore and inflamed, making it the perfect guinea pig for the promises of an icy redemption. In the hours afterward, I realized my knee was no longer hurting. However, this relief subsided throughout the day. The specialist had mentioned it would take more frequent sessions for recovery, so it was expected. She also described that in order for the skin to really reap benefits, multiple sessions per week would be necessary.
After just the one time, I can’t speak to the long-term effects of the practice championed by its supporters: younger skin, boosted metabolism, and faster recovery. I’ll just leave you with this quote with which I unabashedly agree. It was originally published in the Washington Post from Joseph Costello, an exercise physiologist at the University of Portsmouth in the UK: “When you strip down… and put on two pairs of gloves and a pair of socks and go into a chamber that’s set colder than the coldest temperature ever recorded on Earth and stand there for three minutes, that’s a massive opportunity for someone to sustain a placebo effect.”