The evidence that cold water improves mood, anxiety or depression is early and thin. Cold water immersion is not a treatment for any mental health condition, and nothing here should replace advice from your GP. Some studies report short-lived improvements in wellbeing or stress, but they are small, hard to blind and often use self-reported measures.
What reviews and trials have found
The table summarises the sources read. It is not a full literature search.
| Source | Design | What it reported on mood and mental health | Main limits |
|---|---|---|---|
| Cain and colleagues, PLOS ONE, 2025 | Systematic review and meta-analysis of 11 randomised trials, 3,177 participants | Stress fell at 12 hours after immersion, not at other time points. Only one study examined mood, and it found no significant difference from passive recovery. Anxiety and depression were not reported in the included studies | Few trials, small samples, mostly men, mostly single immersions, five studies tested immersion after exercise, self-reported outcomes |
| Buijze and colleagues, PLOS ONE, 2016 (as summarised by the British Psychological Society) | Randomised trial of a 30-day cold-finish shower challenge, more than 3,000 people in the Netherlands | Quality of life was slightly higher after 30 days but the gain was gone when measured later. Anxiety and work productivity did not change. Participants reported more energy | Participants knew what they were doing. The energy effect was self-reported and the mechanism untested |
| Randomised trial in midlife women (described in a 2025 protocol) | 3-week cold-water and breathing programme versus warm showers and slow breathing, in women with high stress and depressive symptoms | Both groups improved in depressive and anxiety symptoms; the cold-water group showed a greater reduction in daily stress rumination | Described second-hand; the trial itself was not opened. Both arms improved, so cold water was not the only change |
| Feasibility trial (described in the same protocol) | Twice-weekly cold-water swimming added to treatment in people with diagnosed depression | Well tolerated, with better subjective wellbeing and sleep quality | Feasibility work shows a plan can be run, not that it works. Described second-hand |
A systematic review of cold-water exposure and mental health, registered in advance as a protocol, was still being planned when the source was published in 2025. Its authors describe the existing evidence as small but growing and fragmented, and set out to pool depression, anxiety, stress and wellbeing outcomes. Until that review reports and others follow, strong claims are running ahead of the data.
Why the evidence is weaker than the headlines
- You cannot be blinded. Everyone in the water knows they are cold. Expectations and enthusiasm can shift self-rated mood even if the body does nothing different. The 2025 protocol names expectancy effects and observer bias as risks.
- Most studies are in healthy or athletic people. Results may not carry over to someone living with depression or anxiety.
- Protocols differ widely. Water temperature, depth, time and frequency all vary between studies, so results do not stack neatly.
- Follow-up is short. The Dutch cold shower gain in quality of life had gone by the later measure. Long-term trials are rare.
- Exercise and company are confounders. Swimming outdoors with friends combines cold, movement, nature and social contact. Separating them is difficult, and the protocol excludes studies with sauna or exercise before the cold exposure for this reason.
- People who stay with it are selected. Surveys of regular cold-water swimmers reflect those who liked it and kept going.
For the wider picture on soreness, immunity and metabolic claims, see cold water immersion health benefits: the evidence.
Cautions that matter if mood is the reason
People often try cold water because they are struggling. That makes the safety side more important, not less. Cold shock raises heart rate and blood pressure, and the Royal Life Saving Society Australia position statement names heart problems, circulatory conditions, high blood pressure and some medicines as reasons for medical screening first. Panic attacks are also listed among the physiological risks of immersion. If you take medication for any condition, ask your GP or pharmacist before starting, and read cold water immersion and medication or conditions.
Do not stop or reduce prescribed treatment because cold water feels helpful. If a plunge helps you feel better for an afternoon, that is worth knowing, but it is not a substitute for assessment.
Where to get support in Ireland
Phone 112 or 999 or go to your nearest emergency department, as the HSE advises if someone is about to harm themselves or others.
- Your GP. The HSE says a GP can support anyone in crisis, and out-of-hours GP services are available. This is the first stop for ongoing low mood, anxiety or worries about medication.
- Samaritans: Freephone 116 123, 24 hours, as listed on the HSE page.
- Text About It: text HELLO to 50808 for a free, 24-hour text conversation with a trained volunteer, per the HSE page.
- Pieta: 24-hour freephone helpline 1800 247 247, text HELP to 51444, and free one-to-one therapy on 0818 111 126, per Pieta's contact page. Pieta supports people at risk of suicide or self-harm and people worried about someone else.
- Mental Health Ireland runs community supports and publishes directories of services; see mentalhealthireland.ie for what is available near you.
- HSE mental health information is at hse.ie/mental-health, including urgent help options.
If you enjoy cold water for its own sake, keep it as an addition to care, not a replacement for it, and follow the cold water safety checklist.
Frequently asked questions
Does cold water treat depression?
There is no reliable evidence it does. A 2025 review found no depression data in its included trials, and a feasibility study only suggests it can be done safely alongside treatment.
Why do people say they feel better afterwards?
Some trials show brief gains in wellbeing or lower stress. These are self-rated, cannot be blinded and may be affected by exercise, company and expectation.
Can I use cold water instead of my medication?
No. Do not change prescribed treatment without speaking to your GP.
Who do I contact in Ireland if I am struggling?
Start with your GP. Samaritans is on 116 123, Pieta on 1800 247 247, and in an emergency phone 112 or 999.
- Cain et al. 2025, PLOS ONE: Effects of cold-water immersion on health and wellbeing, systematic review and meta-analysis
- Frontiers in Psychiatry 2025: protocol for a systematic review and meta-analysis of cold-water exposure and mental health
- British Psychological Society Research Digest: daily cold shower and psychological effects
- HSE: get urgent help for your mental health
- Pieta: contact and helpline details