# Cold water after a sauna: plunges, sea dips and contrast

Source: https://saunabenefits.uk/cold-water/
Author: Kit Ellery · Updated 2026-11-04

**Short answer:** Cold water causes a short-lived increase in inflammation markers, may lower stress the following day and slightly eases muscle soreness after exercise. A cold end to your shower was linked with 29% fewer sick days in one large trial. The big risk is cold water shock, a gasp-and-panic reflex that can be fatal in open water.

## How strong is the evidence for cold water?

| Claim | Grade | Why |
| --- | --- | --- |
| [Less muscle soreness after exercise](/cold-water/cold-plunge-benefits/) | Moderate | Meta-analyses of randomised trials find a small benefit over resting, best at 10–15°C for 10–15 minutes. |
| [Fewer sick days](/cold-water/cold-plunge-benefits/) | Weak | One large Dutch trial of cold-finish showers found 29% less sickness absence but no fewer illness days. |
| [Lower stress](/cold-water/cold-plunge-benefits/) | Weak | A 2025 meta-analysis found lower stress 12 hours after cold immersion, but not at other times, and no effect on mood. |
| [Recovery with hot and cold contrast](/cold-water/contrast-therapy/) | Weak | Better than resting in trials with a high risk of bias, but no better than other recovery methods. |
| Weight loss and brown fat | Weak | Winter swimmers burn more energy in the cold, but no trial shows meaningful weight loss. |
| Immunity | Weak | Claims rest on small studies and the sick-days trial above. |

## What does cold water do to the body?

The moment cold water hits your skin, blood vessels clamp shut, you gasp, your breathing rate jumps and your heart rate and blood pressure spike. This is the cold shock response, and it peaks in the first minute. It eases with repeated dips, on average after about four. Stay in longer and your skin and then your muscles cool, which is what may help sore muscles but eventually leads to weakness and, much later, hypothermia.

## How do you do it safely?

- **Start with a cool shower**, not a plunge.
- **Enter slowly**, breathe out, and wait for your breathing to settle before you go further.
- **Keep it short**: 30 seconds to 3 minutes is plenty for most people.
- **Never go into open water alone**, and stay where you can stand.
- **Skip it** if you have a heart condition, uncontrolled blood pressure or Raynaud's, or have been drinking.

Read [cold water shock](/cold-water/cold-water-shock/) before your first sea or lake dip.

## Frequently asked questions

### Do you have to do a cold plunge after a sauna?

No. A cool shower or fresh air works fine. The long-term Finnish sauna studies didn't depend on cold plunges, and cold water carries risks of its own.

### How cold should a cold plunge be?

Studies mostly used water between 7°C and 15°C. For muscle soreness, 10°C to 15°C gave the best results. Colder water is not more effective and is riskier.

### Is wild swimming after a sauna safe?

It can be, with care. Go in slowly, never alone, stay close to the shore, keep it short and know how to float if cold shock hits. Avoid it if you have a heart condition or have been drinking.

## References

1. [Cain T et al. Effects of cold-water immersion on health and wellbeing: a systematic review and meta-analysis. PLoS One, 2025.](https://pubmed.ncbi.nlm.nih.gov/39879231/)
2. [Buijze GA et al. The effect of cold showering on health and work: a randomized controlled trial. PLoS One, 2016.](https://pubmed.ncbi.nlm.nih.gov/27631616/)
3. [Esperland D, de Weerd L, Mercer JB. Health effects of voluntary exposure to cold water: a continuing subject of debate. International Journal of Circumpolar Health, 2022.](https://pubmed.ncbi.nlm.nih.gov/36137565/)
4. [Tipton MJ et al. Cold water immersion: kill or cure? Experimental Physiology, 2017.](https://pubmed.ncbi.nlm.nih.gov/28833689/)
5. [Machado AF et al. Can water temperature and immersion time influence the effect of cold water immersion on muscle soreness? A systematic review and meta-analysis. Sports Medicine, 2016.](https://pubmed.ncbi.nlm.nih.gov/26581833/)