Cold Therapy (Cryotherapy)

By Donna Wright

Edited and approved by Stephen C. Rose, PhD

Cold therapy has moved well beyond sports medicine and social-media challenges. Cold showers, ice baths, cold plunges, and whole-body cryotherapy are now commonly discussed as tools for recovery, resilience, and healthy aging. Human evidence suggests that cold exposure may support some aspects of physical and mental well-being, but it does not prove that cold plunging extends lifespan on its own.[1,2]

What is cold therapy?

Cold therapy refers to deliberate exposure to low temperatures for a short period. In practice, that can mean cold-water immersion, ice baths, cold showers, whole-body cryotherapy chambers, or local cooling applied to a specific area. Protocols vary widely, but many studies on cold-water immersion use water below 15 °C (59 °F), not a single universal temperature range.[1,2]

How cold exposure affects the body

One reason cold therapy attracts so much attention is that it acts as a controlled physiological stressor. Brief cold exposure activates the sympathetic nervous system, narrows blood vessels in the skin, and increases the body’s demand for heat production. In humans, acute cold exposure can increase energy expenditure and activate brown adipose tissue, which is involved in thermogenesis.[1,3]

That does not mean every cold plunge is automatically “anti-aging.” It means cold exposure can trigger adaptive responses that may be relevant to recovery, metabolism, and stress tolerance when used safely and consistently.[1,2]

Inflammation and recovery

Cold therapy is most firmly established as a recovery tool. It has long been used to help manage soreness and discomfort after exercise and injury. Evidence on inflammation is more mixed than many promotional claims suggest: a 2025 meta-analysis found that whole-body cryotherapy lowered inflammatory cytokines including IL-1β and increased IL-10 in randomized trials, while a 2025 systematic review of cold-water immersion in healthy adults found an acute increase in inflammatory markers immediately and one hour after exposure, alongside some later benefits in stress, sleep, and quality of life.[2,6]

The practical takeaway is that cold therapy may help with recovery and some inflammatory signaling, but it should not be marketed as a universal anti-inflammatory cure.[2,6]

Cardiovascular effects

Cold exposure produces immediate cardiovascular stress. Blood vessels constrict, blood pressure can rise, and cardiac workload increases. In people with coronary artery disease or other cardiovascular disease, cold exposure can reduce myocardial oxygen supply and may increase the risk of ischemia or other adverse responses, especially when cold is combined with exertion.[4]

That matters because cold plunging is often framed as a heart-health practice. For healthy people, brief cold exposure may be tolerated well. For people with cardiovascular disease, uncontrolled hypertension, arrhythmia risk, or other relevant medical conditions, it deserves more caution and medical guidance.[4,5]

Metabolism and glucose regulation

Cold exposure can increase energy expenditure in the short term. A systematic review and meta-analysis found that acute cold exposure increased energy expenditure and brown adipose tissue activity in adults, which helps explain why cold therapy is often linked to thermogenesis and metabolic health.[3]

That said, short-term increases in calorie burning are not the same thing as proven long-term weight-loss or glucose-control benefits in the general population. Cold exposure may support metabolic flexibility, but it is not a substitute for diet, exercise, sleep, or medical care.[1,3]

Immune function

Immune claims around cold plunging are still preliminary. A recent systematic review suggested possible time-dependent effects on immunity and related well-being outcomes, but the overall evidence base remains small and heterogeneous. In one exploratory study of repeated cold-water immersion in healthy men, researchers found no relevant effect on leukocyte counts after three weeks.[2,7]

Stress, mood, and mental well-being

This is one of the more interesting areas of research. Cold-water immersion has been associated with reduced stress at later follow-up in a recent systematic review, and a small 2023 study found improved positive affect and reduced negative affect after a short whole-body cold-water immersion. Participants reported feeling more alert, active, and less distressed after the exposure.[2,8]

That does not make cold therapy a stand-alone treatment for anxiety or depression. It does suggest that brief cold exposure may influence mood and perceived stress in some people, especially when used as one part of a broader health routine.[2,8]

Risks and side effects

Cold therapy is not for everyone. The initial “cold shock” response can trigger hyperventilation and may increase arrhythmia risk and drowning risk, particularly in unaccustomed individuals. A systematic review found that this response habituates after repeated immersions, but adaptation does not eliminate risk.[5]

Potential complications of excessive or poorly supervised cold exposure include hypothermia, frostbite, pain, numbness, and dangerous cardiovascular strain. Anyone with cardiovascular disease, significant blood pressure problems, a history of cold intolerance, or conditions that impair thermoregulation or sensation should speak with a medical professional before trying cold plunges or cryotherapy.[4,5]

Cold therapy as a longevity tool

Cold therapy is a possible support tool, not a magic longevity intervention. The strongest current evidence points toward roles in recovery, acute metabolic activation, stress adaptation, and possibly mood. Evidence for direct effects on lifespan or for long-term prevention of age-related disease in humans remains limited.[1,2]

When used safely, cold therapy may fit into a broader healthy-aging strategy that also includes regular exercise, good nutrition, quality sleep, stress management, and medical care. That is a much stronger foundation for longevity than any plunge alone.[1–5]

References

Kunutsor, S.K.; Lehoczki, A.; Laukkanen, J.A. The Untapped Potential of Cold Water Therapy as Part of a Lifestyle Intervention for Promoting Healthy Aging. GeroScience 2025, 47, 387–407.

Cain, T.; Brinsley, J.; Bennett, H.; Nelson, M.; Maher, C.; Singh, B. Effects of Cold-Water Immersion on Health and Wellbeing: A Systematic Review and Meta-Analysis. PLoS ONE 2025, 20, e0317615.

Huo, C.; Song, Z.; Yin, J.; Zhu, Y.; Miao, X.; Qian, H.; Wang, J.; Ye, L.; Zhou, L. Effect of Acute Cold Exposure on Energy Metabolism and Activity of Brown Adipose Tissue in Humans: A Systematic Review and Meta-Analysis. Front. Physiol. 2022, 13, 917084.

Ikäheimo, T.M. Cardiovascular Diseases, Cold Exposure and Exercise. Temperature (Austin) 2018, 5, 123–146.

Barwood, M.J.; Eglin, C.; Hills, S.P.; Johnston, N.; Massey, H.; McMorris, T.; Tipton, M.J.; Wakabayashi, H.; Webster, L. Habituation of the Cold Shock Response: A Systematic Review and Meta-Analysis. J. Therm. Biol. 2024, 119, 103775.

He, J.; Zhang, X.; Ge, Z.; Shi, J.; Guo, S.; Chen, J. Whole-Body Cryotherapy Can Reduce the Inflammatory Response in Humans: A Meta-Analysis Based on 11 Randomized Controlled Trials. Sci. Rep. 2025, 15, 7759.

Versteeg, N.; Clijsen, R.; Hohenauer, E. Effects of 3-Week Repeated Cold Water Immersion on Leukocyte Counts and Cardiovascular Factors: An Exploratory Study. Front. Physiol. 2023, 14, 1197585.

Yankouskaya, A.; Williamson, R.; Stacey, C.; Totman, J.J.; Massey, H. Short-Term Head-Out Whole-Body Cold-Water Immersion Facilitates Positive Affect and Increases Interaction between Large-Scale Brain Networks. Biology 2023, 12, 211.