Popular forms of cold therapy include cold water therapy, like ice baths and chilled plunges, and whole-body cryotherapy (WBC), which uses air, as opposed to water, to achieve potentially therapeutic results. WBC involves brief bouts in a small chamber (also known as a cryochamber) that’s been cooled to temperatures between minus 200 and minus 300 degrees Fahrenheit, according to the U.S. Food and Drug Administration (FDA). Proponents claim these chilly therapies can relieve chronic pain, speed up muscle recovery, promote weight loss, ease depression, and more. But what’s fact and what’s fiction? “It’s fairly safe to say, when it comes to cryotherapy, the anecdotal evidence far outstrips the research right now,” says researcher Shawn Arent, PhD, CSCS, professor and chair of exercise science at the University of South Carolina in Columbia, South Carolina. Still, many people report positive experiences with cryotherapy, which suggests there may be something to it, he adds. Read on for how cryotherapy might benefit your overall health and wellness. To understand why, we first need to understand what happens to the body when it becomes chilled and reheated. First, your body responds to cold temps by constricting your blood vessels (known as vasoconstriction), sending all your blood toward your organs. When this happens, your blood acquires more oxygen and nutrients, explains Gregg Larivee, doctor of chiropractic and founder and CEO of Integrated Medical Center in Jupiter, Florida. Then, once you leave the cold and your body warms up again, your blood vessels expand (known as vasodilation), sending oxygen- and nutrient-rich blood back to your tissues. This increased blood flow flushes out inflammation and toxins you built up during your workout, helping kick-start recovery, Dr. Larivee explains. For example, a study published in February 2021 in The Journal of Strength and Conditioning Research out of China found that WBC reduced muscle damage and inflammation in middle- and long-distance runners better than other forms of cryotherapy and no cryotherapy (control). Unfortunately, the study was small (only 12 runners), so it’s hard to say how these findings might apply to greater populations. That said, past studies also reported decreases in muscle pain and inflammation from using WBC post-exercise, according to a past opinion paper. However, the authors of another past systematic review concluded that there isn’t enough evidence to determine whether WBC actually helps recovery after exercise better than rest. Dr. Arent also warns that cryotherapy may limit how well your muscles adapt to resistance training. “[Cryotherapy] appears to reduce muscle protein synthesis, [the process that drives responses to exercise], so strength gains are not as great,” he says.
2. May Improve Sleep
Based on the current evidence, cryotherapy may help with sleep, according to Arent. For example, the aforementioned Chinese study in middle- and long-distance runners not only found that WBC reduced muscle damage and inflammation after exercise but also that subjects reported better sleep quality after WBC than other forms of cryotherapy. In addition, a study published in March 2019 in BMC Research Notes found that soccer players moved less during the night (measured via wrist devices) and reported better sleep after three minutes of partial-body cryotherapy (PBC) than after shorter sessions. (PBC is similar to WBC, except that your head and neck are outside the cryochamber.) And a study published in July 2019 in the European Journal of Sport Science reveals similar findings: Active men who received WBC after an evening workout tossed and turned less during the night and reported better sleep than those who didn’t. Researchers speculate that cryotherapy may help us sleep by helping to activate the parasympathetic nervous system. This is the “rest and digest” side of the autonomic (or “automatic”) nervous system, which takes over managing your bodily functions when we feel calm and safe, explains the Cleveland Clinic. And when the parasympathetic nervous system is activated, we tend to be in a relaxed state. However, more research is needed to determine if and how cryotherapy may improve sleep in nonathletic populations, and larger studies are necessary to more fully understand the relationship between cold therapy and sleep quality.
3. May Improve Chronic Pain
Cryotherapy may relieve chronic pain in a couple of different ways. First, cold is a known short-term analgesic (or pain reliever). Think: Placing an ice pack on a sprained ankle. Scientists believe cold works by slowing nerve transmission (when a nerve fires a signal to the brain) in pain cells, per a review published in December 2020 in Pain and Therapy. Cryotherapy may also lessen pain by lowering inflammation, a hallmark of inflammatory-related chronic pain conditions like rheumatoid arthritis and ankylosing spondylitis (an inflammatory disease of the spine), according to a research paper published in December 2019 in Nature Medicine. In fact, after reviewing 25 studies, the authors of the 2020 review in Pain and Therapy concluded that cryotherapy could be an easy, low-risk option for managing chronic pain. In particular, pain associated with chronic conditions like rheumatoid arthritis and ankylosing spondylitis. WBC and ice application were the two cryotherapy methods found to offer pain relief. However, research on the long-term effects of cryotherapy on chronic pain, and more standardized treatment protocols, is needed.
4. May Treat Some Chronic Skin Conditions
WBC may also help lower inflammation and relieve itching in people with atopic dermatitis (eczema), a chronic skin condition characterized by dry, inflamed skin. For a small past study, 16 adults with mild to moderate atopic dermatitis underwent WBC at -166 degrees F for one to three minutes, three times a week for one month. Atopic dermatitis symptoms improved for most patients, though the study sample was too small to draw meaningful conclusions. Currently, and a note of importance, the American Academy of Dermatology Association discourages the use of WBC as a treatment for atopic dermatitis.
5. May Aid Weight Loss
Spending time in the cold may speed up your metabolism as your body works to stay warm. Theoretically, if you increase your calorie burn, you may be able to create the calorie deficit needed to lose weight. In a study published in April 2021 in the International Journal of Environmental Research and Public Health, 16 control lean women and 15 obese women underwent PBC for 150 minutes a day at -202 degrees F, for five days. By the end of the study, the lean women were burning 8.2 percent more calories at rest (known as resting energy expenditure, or REE), while the obese women were burning 5.5 percent more calories at rest than they were on day one. While these findings are interesting, we can’t know how long these changes in REE would last, or whether they would result in weight loss, and because this study was so small, further research in larger populations are needed.
Uses and Health Benefits of Medical Cryotherapy
Some forms of cryotherapy — namely, cryoablation or cryosurgery (a surgical procedure using extreme cold) — are used medically by surgeons and other types of certified healthcare providers, and for specific procedures aiming to address certain conditions. For example, a dermatologist may use cryoablation to treat abnormal tissue, and some surgeons may use this technique to destroy certain cancers. It’s important to note that cryoablation is a different form of cryotherapy than the healing, supportive approaches discussed above. That said, here are two medical benefits to cryotherapy techniques used in a clinical setting:
1. Treat Some Cancers
Cryotherapy is a common method for treating some cancers, including prostate and liver cancer, according to the Cleveland Clinic. The therapy is called cryoablation, and it involves freezing tumor cells inside the body. The tumor cells can’t survive extreme cold, and die as a result, according to a past research article. Cryoablation is a minimally invasive procedure. To do it, the doctor inserts an instrument called a cryoprobe through a small incision in the skin and applies the cold (a substance like liquid nitrogen or argon gas) with a spraying device, per the Cleveland Clinic. However, cryoablation can only be used to treat tumors that can be seen through imaging tests, such as mammograms, according to the National Cancer Institute (NCI). Moreover, doctors are still unsure how cryoablation might control cancer or impact life expectancy over the long term, per the NCI.
2. Treat Abnormal Skin Tissues
Cryotherapy is also sometimes used to treat benign (not cancerous), precancerous, or superficially cancerous skin cancer, according to the Memorial Sloan Kettering Cancer Center. Freezing specific areas of the skin causes it to blister and peel off, allowing new, healthy skin to grow in its place, explains the Cleveland Clinic.
