Cold Therapy and Cold Water Explained Simply

1. What It Is About

Cryotherapy involves the targeted use of cold. There are local applications such as ice packs, cold air or a cold bath for a single body part. There are also whole-body applications, for example in a cryotherapy chamber (also known as a cryosauna) or a cold-water immersion. These methods originate from physical medicine and sports rehabilitation, where they have been used for decades to relieve pain, reduce inflammation and support recovery. Cold applications date back to antiquity; modern forms use precisely controlled temperatures. Local cold primarily works by constricting blood vessels and slowing nerve conduction. The temperature, duration and whether dry or wet cooling is used vary widely between studies, making direct comparisons difficult.

2. What Research Shows

The best-studied application of cold is for the musculoskeletal system, including muscles, tendons and joints. A review of 32 controlled studies on delayed-onset muscle soreness found that applying cold within one hour after exercise reduced pain in the first 24 hours; no difference was observed after 24 hours. Cold-water immersion was among the effective methods 3.

In 60 people with fibromyalgia, a condition characterised by widespread pain, whole-body cryotherapy in a cold chamber was compared with a rest phase. After four weeks, the cold group showed greater improvements in pain, disease burden and severity than the comparison group. However, the study was open-label: participants knew which treatment they were receiving 1.

In 80 patients after bypass surgery, either ice was applied to the wound area or a relaxation exercise was performed before drain removal. Immediately afterwards, pain was lower in both groups than in the control group; there was no difference between ice and relaxation 2.

In 60 participants with exercise-induced muscle damage, a cold-water bath was compared with ice massage. In the cold-water group, measurement values normalised faster after 72 hours; strength, jump power and pain nearly returned to baseline levels 6.

After knee surgery, a review found lower pain scores on the first and second days post-operation when cold therapy was applied 5.

In 35 people with restless legs syndrome, a condition involving an irresistible urge to move the legs, four weeks of whole-body cryotherapy improved symptom severity and quality of life; local cold therapy improved sleep quality 4.

3. What Remains Unclear

Many questions remain unanswered. Many studies had small sample sizes, short durations and lacked blinding — meaning participants knew which treatment they received, potentially amplifying perceived effects. Effects on the whole body, such as on metabolism, are currently only suggested, not confirmed. Negative findings are less likely to be published, which may skew the overall picture. There are no standardised guidelines on temperature, duration or application method, making studies difficult to compare. Comparisons with physiotherapy or pain medication are also lacking. The long-term durability of effects remains largely unexamined.

4. What This Means in Everyday Practice

The most reliable evidence concerns local cold applications to muscles and joints, particularly in the period immediately following surgery. Within the studied timeframes, controlled trials show effects on pain. For cryotherapy chambers and regular cold baths, there are indications but no confirmed results. Those interested can review the conditions under which effects were observed in the cited studies. Future research should clarify optimal temperature, duration and frequency, as well as how cold therapy compares to physiotherapy or medication. It also remains to be determined whether observed effects persist over weeks or months.

All details with study numbers and sources: detailed page on cryotherapy and cold-water immersion. For children: Cryotherapy and cold-water immersion for children.