In the blog category “From our community”, we address treatments that are being discussed controversially by people affected by Long COVID and health care professionals. In the Altea forum, in stories, and in discussions with those affected, we have seen a number of treatment suggestions that are not officially recommended (yet). To help judge the safety and effectiveness of these treatments, we are exploring the science behind them. We are aiming to provide an overview of the available evidence, evaluate whether or not the available data is reliable, and summarize which risks might be associated with these treatments. Today, we will cover whole-body cryotherapy.
Application in sports medicine
Over the past years, whole-body cryotherapy has become popular in sports medicine due to its assumed benefits in preventing injuries, reducing pain and inflammatory symptoms, and boosting athletic performance. It is also claimed to bring a benefit in many other conditions like multiple sclerosis, arthritis, asthma, migraines, fibromyalgia, depression, anxiety and, more recently, also Long COVID.
The precise mechanisms of whole-body cryotherapy are unknown but the theory behind is that extreme cold can lessen inflammation by increasing levels of anti-inflammatory and decreasing levels of pro-inflammatory molecules.
Whole-body cryotherapy also supposedly reduces the breakdown of muscles, increases bone mineral density and hemoglobin values, and alters certain hormone levels (such as endorphins, also called happy hormones). However, the vast majority of studies investigating its underlying mechanisms included only a small number of participants, and results from small-scale studies are not very reliable.
While there are no scientifically proven advantages of whole-body cryotherapy, dermatologists warn that very cold temperatures can cause substantial skin damage. Reported skin injuries associated with whole-body cryotherapy include frostbite, a frozen limb, and rashes. Other potential adverse effects of this extreme cold treatment include suffocation, sudden and temporary loss of memory, and eye injuries.
A study on whole-body cryotherapy for Long COVID was retracted.
Despite the lack of scientific evidence for its clinical benefits, proponents of whole-body cryotherapy claim that it might also improve some of the symptoms of Long COVID.
An article published in 2022 gained attention (at least within the community) by suggesting that whole-body cryotherapy might help restore smell in Long COVID patients. In this small pilot study, 45 patients with hyposmia (reduced smell) or anosmia (loss of smell) (32 women, 13 men) were divided into three groups: a low-dose group of patients who had one session per day for two days in a row, a high-dose group of patients who had one session per day for five days in a row and a control group (no treatment).
Results showed that whole-body cryotherapy was safe, with no participants experiencing adverse effects. One week after treatment, participants in the high-dose group reported significant improvements in their sense of smell compared with participants in the control group. While these findings initially looked promising, the article was retracted (withdrawn) shortly after its publication. The authors requested the retraction of the article themselves due to insufficient ethical clearance.
Retraction is a serious matter in scientific publishing, and it often implies that results are no longer considered trustworthy due to research misconduct or error. Despite the retraction, most of these articles can still be found on the internet further spreading false information. It is therefore essential that we always check the source of the article and be skeptical of sensational news.
Confidence level of different forms of publication.
Low-level evidence: Case reports
The potential benefit of whole-body cryotherapy for treating symptoms of Long COVID was also explored in case reports. A case report is a detailed description of the symptoms, diagnosis, treatment, and follow-up of an individual patient. Although they can provide some preliminary evidence, case reports are considered the lowest level of scientific evidence and cannot establish the effectiveness of a therapy.
The first article reports on changes in the physical and mental functioning of seven Long COVID patients who underwent whole-body cryotherapy (ten sessions within two weeks). Patients also received other interventions, such as physiotherapy, physical exercise, a nutritional program, and psychological support. Despite these other interventions, the study authors claim that improvements in quality of life, sleep, mood, fatigue, dyspnea, and pain mainly derived from whole-body cryotherapy.
Another case report describes a 75-year-old man with Long COVID who experienced improvements in breathing and sleep quality after the first two-minute session of whole-body cryotherapy. Because he also received a range of other interventions to treat Long COVID, this report cannot determine to what extent whole-body cryotherapy was responsible for the observed improvements. However, the authors believe that the cold treatment was the turning point in improving his symptoms.
In conclusion, there is currently no research to support the use of whole-body cryotherapy for the treatment of Long COVID. Although some case reports and anecdotal evidence suggest that certain patients with Long COVID might profit from this procedure, high-quality clinical studies are needed to determine the beneficial effects of whole-body cryotherapy. For now, this treatment remains unproven for patients with Long COVID and can even be associated with risks.
