# Contrast therapy: does switching hot and cold work? Source: https://saunabenefits.uk/cold-water/contrast-therapy/ Author: Kit Ellery · Updated 2026-11-04 **Short answer:** Alternating hot and cold water eased muscle soreness and strength loss after exercise better than resting in a review of 18 trials, but all had a high risk of bias and contrast was no better than other recovery methods. Going from a sauna to cold water strains the heart briefly, so build up slowly and skip it if you have heart problems. **Evidence grade:** Weak evidence. Small or short studies, surveys, or results that are mixed. ## What is contrast therapy? Moving between heat and cold: a sauna or hot tub, then a cold plunge, shower or sea dip, then back again. It's a centuries-old habit in Finland, Russia and Japan, and it's the format of most of the new UK sauna clubs, many of which sit by the sea or a river. In sports medicine, contrast water therapy usually means alternating hot and cold water baths for a minute or so each, several times over. ## What does the research show? A 2013 systematic review pooled 18 trials of contrast water therapy after hard exercise. Compared with passive rest, contrast therapy led to: - less muscle soreness at every time point from 6 to 96 hours, and - less loss of muscle strength. But all 18 trials had a high risk of bias, and when contrast therapy was compared with other methods, including cold water alone, warm water, compression and active recovery, none clearly beat the others. So it seems better than doing nothing, and about as good as other options. [Cold plunge benefits](/cold-water/cold-plunge-benefits/) and [sauna for muscle recovery](/benefits/muscle-recovery/) look at each half on its own. There are no good long-term trials of the sauna-and-sea routine for general health. Finnish winter swimmers who combine cold dips with saunas two or three times a week show signs of adapting to both heat and cold, but that tells us about physiology, not health outcomes. ## What happens in your body when you switch? - **In the heat**, blood vessels in your skin open wide, heart rate climbs and blood pressure, after a while, falls. - **In the cold**, those vessels clamp shut within seconds. You gasp, breathe fast and your heart rate and blood pressure jump. This is the [cold shock response](/cold-water/cold-water-shock/). - **As you warm up again**, the vessels reopen and you often feel a tingling glow. That rapid switch is why many people find contrast so invigorating, and why it is a real strain on the heart for a minute or two. ## What is a safe contrast routine for beginners? 1. **Sauna** for 8 to 12 minutes. See [how long to stay in a sauna](/how-to/how-long-to-stay-in-a-sauna/). 2. **Cool shower** for 30 seconds to a minute, gradually turning it colder over a few visits. 3. **Rest** for 5 to 10 minutes, sitting down, with a drink of water. 4. **Repeat** once or twice. When you're used to it, you can swap the shower for a plunge or a dip. Get in slowly, breathe out, and keep it short. Never dive or jump into cold water straight from a hot sauna. ## Should you finish on hot or cold? There's no evidence either way. Finnish tradition often ends with a cold dip and a long rest; many people prefer to finish in the warm so they don't leave chilled, especially outdoors in winter. If you're using contrast in the evening and want to sleep, finishing warm and resting before bed is probably the better choice, as explained in [sauna and sleep](/benefits/sleep/). ## Who should skip contrast therapy? Anyone who should avoid either half. That includes people with heart disease, heart rhythm problems or uncontrolled blood pressure, people with Raynaud's, and anyone who has been drinking. The full list is in [who should avoid saunas](/safety/who-should-avoid-saunas/). ## Frequently asked questions ### Should I end on hot or cold? There's no good evidence either way. Many people end with cold for alertness and warm up naturally afterwards; others end with heat to relax. In winter outdoors, finishing warm and dressing quickly is the safer choice. ### How many rounds of contrast should I do? Two or three rounds of sauna and cool-down is the traditional pattern. There's no evidence more rounds bring more benefit. ### Is contrast therapy safe for the heart? For healthy people, usually. The switch from heat to cold causes a sudden rise in heart rate and blood pressure. People with heart disease, uncontrolled blood pressure or a history of heart rhythm problems should avoid sudden cold plunges unless their doctor says otherwise. ### How many rounds of hot and cold should you do? Two or three rounds is typical in UK sauna clubs and in Finland. The sports trials used three to seven short switches between hot and cold water. More rounds haven't been shown to add benefit. ## References 1. [Bieuzen F, Bleakley CM, Costello JT. Contrast water therapy and exercise induced muscle damage: a systematic review and meta-analysis. PLoS One, 2013.](https://pubmed.ncbi.nlm.nih.gov/23626806/) 2. [Søberg S et al. Altered brown fat thermoregulation and enhanced cold-induced thermogenesis in young, healthy, winter-swimming men. Cell Reports Medicine, 2021.](https://pubmed.ncbi.nlm.nih.gov/34755128/) 3. [Heinonen I, Laukkanen JA. Effects of heat and cold on health, with special reference to Finnish sauna bathing. American Journal of Physiology, 2018.](https://pubmed.ncbi.nlm.nih.gov/29351426/) 4. [Tipton MJ et al. Cold water immersion: kill or cure? Experimental Physiology, 2017.](https://pubmed.ncbi.nlm.nih.gov/28833689/)