Whole-body cryotherapy for stress, sleep, and wellbeing: a narrative review Christian J. Wiedermann* [1] , Giuliano Piccoliori [1] , Adolf Engl [1]

https://www.academia.edu/2997-9196/2/4/10.20935/MHealthWellB7937 Whole-body cryotherapy (WBCT), which involves short exposure to extremely cold air, is increasingly promoted for stress reduction, sleep enhancement, and general wellbeing. While commercial interest has grown rapidly, regulatory guidance is absent, and professional consensus is lacking. This narrative review aimed to synthesize the proposed mechanisms of action, summarize the efficacy for wellness-related outcomes, and critically assess the safety and quality of the supporting evidence. A narrative review of mechanistic studies, clinical trials, and systematic reviews was conducted to examine WBCT in healthy individuals and patients with stress- or inflammation-related conditions. Relevant articles were identified through targeted searches of PubMed and the citation databases. Evidence from closely related modalities, such as cold-water immersion, was also considered when direct data on WBCT were sparse. WBCT appears to exert effects through acute neuroendocrine, vascular, and immunological stress responses, potentially enhancing mood, sleep, and subjective vitality of the participants. Small, randomized trials and meta-analyses have reported modest improvements in anxiety, depressive symptoms, and sleep quality. However, methodological limitations, including small sample sizes, heterogeneity of protocols, and lack of blinding, reduce the reliability of these findings. Serious adverse events are rare; however, safety concerns persist, particularly in unsupervised settings. Regulatory bodies do not endorse WBCT, and no clinical guidelines currently support its routine usage. Consensus statements from professional bodies are limited to safety-related recommendations. Although WBCT may offer short-term wellness benefits in select populations, the current evidence is insufficient to support its use as a broader health or preventive intervention. Future high-quality trials are needed to clarify the efficacy, optimize protocols, and define safety profiles across populations. Until then, WBCT should be regarded as an experimental wellness modality, used cautiously and under supervision.