Not a day goes by that Steelers defensive end Cam Heyward doesn’t feel aches and pains. But exactly where he hurts is top secret. You just can’t let ill-willed offensive ends know which aching body parts to target.

So he calls it “general soreness.”

But after a game and practices, those aches and pains become ACHES and PAINS. So the Steelers’ first-round NFL draft choice in 2011 has been using a new way to battle the pain, remain more flexible and boost energy.

He freezes himself. But obviously not the ice cube kind of frozen.

Through a high-tech method still not fully on the American radar, whole body cryotherapy is gaining popularity, with professional athletes and celebrities leading the charge.

About every other day, Heyward, 27, of Pine heads to Pittsburgh Cryotherapy at the Legacy Medical Center in Peters, where he enters a cylindrical machine resembling a giant pop can that uses liquid nitrogen to generate temperatures that can dip well below minus 200 degrees Fahrenheit.

Exposure to extremely low temperatures for two to three minutes shocks the body, constricting blood vessels and sending blood rushing to protect the heart, brain and other vital organs for the sake of survival. When he’s done, he feels the flash of blood rushing back to the extremities. That dynamic blood flow washes away inflammatory proteins and toxins with fresh, newly oxygenated blood returning to the muscles, skin and extremities, accelerating natural healing power and boosting energy reserves. So says Tom Burnett, a sports medicine physician who owns Legacy with his brother Matt Burnett, a chiropractor who travels with the Steelers.

What Tom Burnett describes as “a sexy high-tech ice bath” was invented in Japan in the late 1970s to treat arthritis. It’s now used against muscular and joint aches, pains, anxiety and depression, various inflammatory conditions caused by autoimmune disorders including rheumatoid arthritis, multiple sclerosis, osteoporosis and even tinnitus, among others. With the body spending 600 to 800 calories to warm up after a treatment, some are using cryo to lose weight.

Research from Europe, particularly Poland, has documented multiple benefits from whole body cryo. But people should consult their physicians, experts advise, with special precautions for those with very high blood pressure or heart disease, given the dramatic impacts on blood flow.

On a recent morning, Mr. Heyward wore only black shorts, along with mittens and foot covers, when he stepped inside the TitanCryo machine with only his head showing to avoid fainting from the nitrogen gases. Matt Burnett programmed the machine to cool to minus 210 degrees with Heyward stoically in place for three minutes. He said he has experienced even colder temperatures, but treatments never go beyond three minutes, to avoid frostbite.

Once the door opened, Heyward’s skin felt as cold as a drinking glass filled with ice water.

“I do get cold, I admit that,” Mr. Heyward said. “I feel a little bit numb but not a bad numb. It’s a good feeling. It’s refreshing like an energy burst.”

“It takes the edge off,” he said. “It opens me up.”

Pittsburgh’s hot new cold trend

Pittsburgh Cryotherapy in Peters was first to open last September, followed in December by Cloud Cryotherapy in the Strip District, then CRYO PGH in East Liberty in January.

The Burnett brothers say many Steelers now use cryotherapy at their facility to tune up for games, reduce pain and promote healing afterward. Already, Tom Burnett said, they are close to being fully booked and recently acquired another machine to accommodate people as tall as 7 feet. That’s important given the growing number of high school, college and professional athletes using cryo.

Cloud Cryo owner Tom Rodgers said he’s treated players from visiting Major League baseball teams, with the Detroit Tigers as an example, along with some notable actors visiting Pittsburgh. Actors claim that cryo makes them look younger with improved skin tone, he said. Demi Moore is a proponent, and there are reports that some “Dancing With the Stars” participants have used the therapy.

Prices are similar at all three locations, with individual sessions in the range of $50 to $60, each with package deals at about $25 per treatment. The sessions aren’t covered by insurance. All three centers report that they treated many Pittsburgh Marathon participants before and after this year’s race.

Alyssa Chance, 40, of Brighton Heights underwent two sessions prior to the marathon in pursuit of a personal best but experienced hip bursitis about mile 7 that led to pain and swelling. She finished without a personal best time. The next day, she returned to Cloud Cryotherapy to treat her hip pain.

“That evening, the swelling had gone down, and later that day and the next day, it was less painful,” she said. “I felt it definitely helped with inflammation.

“I’d say it lessened the general soreness,” she said.

Cold claims

While it’s theoretically clear why whole body cryotherapy works, experts generally agree more research is necessary to fully evaluate the treatments’ benefits and risks.

For now, any proclamation of health benefits from cryo in the United States can’t be sanctioned.

The U.S. Food and Drug Administration says it regulates medical devices “when the manufacturer promotes the device for medical purpose claims, for example: reducing muscle soreness, shortening injury recovery time or increasing blood circulation.” But to date, the FDA “has not cleared or approved any whole body cryogenic devices.”

“If the manufacturer only promotes the product for nonmedical purpose claims, for example, being used only for comfort, soothing or relief, this product would not meet the definition of a medical device.”

Still, testimonials of health benefits abound.

Jennifer Highfield, 43, of Carnegie was diagnosed with rheumatoid arthritis in early 2015 with pain, stiffness and swelling in her hands. After a year of taking three daily doses of pain medications, she said, she still felt routine pain. That’s when she tried CRYO PGH, owned and operated by Jessica McGartland, 39, of Ligonier, in the same building where she works. She underwent seven treatments before feeling any benefits. Now she’s hooked.

“I do this and get through the rest of the day, and when I get home I’m not crashing on the couch,” she said. Mostly pain free now, she said, she still takes a daily preventive dose of pain medicine. “I wake up and can start the day without allocating a half-hour to loosening up. The improved quality of life is worth the time and investment of doing this three times a week.

“This was a no-brainer,” Highfield said. “It doesn’t hurt, and it has worked out very well for me.”

Another local sports legend, Penguins great Pierre Larouche, said treatments every two weeks help him withstand the chronic pain from two back and two hip surgeries and other surgeries to his shoulder, hands and knees resulting from his National Hockey League career, which lasted from 1974 through 1988.

“I thought I’d give it try,” he said. “I go in and walk out with a rush of blood that is amazing, amazing, amazing.”

Larouche, 60, of Collier, seemed buoyed immediately after a recent treatment: “I always have soreness, but this is good for a week,” he said, noting that afterward, “you feel a rush of heat that feels so good.”