Cold-Water Immersion: Evidence Summary
A plain summary of research on cold plunges, ice baths and cold showers: soreness, stress, sleep, immunity and inflammation findings, the cold shock danger, and who should avoid them.
Content last updated . This page has not been medically reviewed.
What research shows
Labels: promising but limited, mixed, no good evidence of benefit, insufficient evidence. See how we label evidence.| Outcome | Finding | Label |
|---|---|---|
| Muscle soreness after exercise | A Cochrane review of 17 small, low-quality trials found some soreness benefit versus rest; adverse events mostly not tracked [4] | promising but limited |
| Sickness absence | Randomized trial of 3,018 adults: 29% less self-reported sickness absence, but no difference in illness days [5] | mixed |
| Stress | Meta-analysis of 11 trials: lower stress at 12 hours but not at other time points [6] | mixed |
| Sleep, quality of life | Improvements seen in the same review; evidence base is few trials, small samples [6] | promising but limited |
| Mood | No significant benefit [6] | no good evidence of benefit |
| Inflammation | Measures rose immediately and at 1 hour after immersion [6] | no good evidence of benefit |
| Weight or fat loss, longevity | Proper evidence not found in the sources we read | insufficient evidence |
Limits
- Most trials are small, with varied methods, so results may not apply to you.
- Feeling more alert or less sore soon after is not a lasting health outcome; see biomarkers vs clinical outcomes.
- Cold after strength training may reduce training gains: see recovery claims vs long-term adaptation.
- The meta-analysis covered healthy adults only, so results do not cover people with heart disease or other conditions. [6]
Related guides
Cold and heat exposure overview, warm vs cold water immersion, and recovery after exercise.Frequently asked questions
Does an ice bath reduce soreness?
Some benefit versus rest was found in small, low-quality trials. [4]
Do cold plunges boost immunity?
The evidence is mixed. A trial found fewer sick days taken, not fewer days ill. [5]
Does cold water reduce inflammation?
In a meta-analysis, inflammation measures rose right after immersion. [6]
Who should avoid cold plunges?
Anyone with heart conditions or high blood pressure should ask a clinician first; cold water shock can affect heart and breathing. [2] People with past immersion pulmonary edema are advised to avoid cold water. [3]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Safety first
Cold water can be dangerous. Sudden skin cooling triggers the cold shock response, which can be life-threatening. [1] This page gives no temperatures or times, and does not suggest breath-holding or forced fast breathing, which add risk in water. Do not practice alone or in open water you do not know. Talk with a clinician first if you have heart disease, blood pressure problems, take blood pressure medicines, are pregnant or are an older adult. See cold-water immersion and contrast practices and hydrotherapy safety. In an emergency in the US call 911.
Risks first
An NHS ambulance service explains that cold water shock narrows skin blood vessels, speeds the heart, causes an involuntary gasp and can make breathing rates change uncontrollably, which raises the chance of inhaling water; it can cause heart attacks even in relatively young and healthy people. [2] If you are unexpectedly in cold open water, it advises waiting for the first effects to pass, floating on your back and calling for help. [2] Anxiety can magnify parts of the response. [1]
Immersion pulmonary edema (fluid in the lungs) is rare but can be fatal and recurrent. Risk factors include cold water, age over 50 and existing heart disease. [3]
References
- Barwood MJ et al. Acute Anxiety Predicts Components of the Cold Shock Response on Cold Water Immersion. Front Psychol 2018. PubMed 29695988. Read 2026-10-22.
- East Midlands Ambulance Service (NHS). Thinking of swimming in open water? Don't risk it. Read 2026-10-22.
- Kumar M, Thompson PD. A literature review of immersion pulmonary edema. Phys Sportsmed 2019. PubMed 30403902. Read 2026-10-22.
- Bleakley C et al. Cold-water immersion (cryotherapy) for preventing and treating muscle soreness after exercise. Cochrane Database Syst Rev 2012. PubMed 22336838. Read 2026-10-22.
- Buijze GA et al. The Effect of Cold Showering on Health and Work: A Randomized Controlled Trial. PLoS One 2016. PubMed 27631616. Read 2026-10-22.
- Cain T et al. Effects of cold-water immersion on health and wellbeing: a systematic review and meta-analysis. PLoS One 2025. PubMed 39879231. Read 2026-10-22.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.