Contrast therapy: how to do sauna and cold plunge rounds

Contrast therapy means alternating between heat and cold, usually a sauna and a cold plunge or ice bath, with rest in between. It’s the backbone of sauna culture in Finland and the Baltics, and it’s now how most UK sauna clubs are set up: a hot cabin, a cold tub or the sea, and somewhere to sit and recover.

People do it because it feels good. Many describe feeling calm, alert and pleasantly tired afterwards. Research into specific health benefits is still developing, so treat it as a ritual you enjoy rather than a treatment.

A typical round

1. Heat: 8 to 15 minutes. Traditional saunas usually run between 70 and 100°C. Stay until you’re properly warm and sweating, not until you’re desperate to get out.
2. Cold: 30 seconds to 3 minutes. Cold plunges are often kept between 3 and 12°C. Get in slowly, keep your breathing steady and get out while it still feels manageable.
3. Rest: 5 to 15 minutes. Sit or lie down somewhere comfortable, wrapped up if you’re outside. This is when many people say they feel the effect most.

Repeat for two to four rounds. Many people like to finish on cold, but there’s no rule. If you’re shivering at the end, finish with a warm shower or a short final sauna.

Your first session

Start gently. Spend 5 to 10 minutes in the sauna, try a cold shower or 15 to 30 seconds in the plunge, and see how you feel. Build up over several visits rather than in one go. Shorter time in the cold is still contrast therapy, and there’s nothing to be gained from pushing through.

Getting into cold water

The first minute in cold water is the hardest. Your body reacts with a sharp gasp and fast breathing, known as cold water shock. It passes, but it’s why the way you get in matters:

• Lower yourself in slowly. Don’t jump or dive, especially into open water.
• Breathe out slowly and steadily until your breathing settles.
• Never hold your breath or put your head under while your breathing is still fast.
• Keep your hands out of the water at first if it helps. Hands and feet feel the cold most.

Sea and lake plunges

Many coastal and lakeside saunas use the sea or a lake as their cold plunge. Open water brings extra risks: currents, tides, uneven ground and water that can be much colder than it looks. Follow the venue’s guidance, stay within your depth, and never go in alone. If you’re used to a heated sauna but new to open water, stay in for less time than you would in a plunge tub.

Staying safe

• Drink water throughout. Heat and cold together are more tiring than they seem.
• Don’t drink alcohol before or during a session.
• Get out if you feel dizzy, sick, numb or confused, and tell a member of staff.
• Stand up slowly after the sauna and after resting, as your blood pressure can drop.
• Speak to your GP before trying contrast therapy if you have a heart condition, high blood pressure, Raynaud’s, epilepsy or are pregnant.

Where to try it

Plenty of UK saunas have a cold plunge on site, and some venues specialise in cold water. Browse saunas or see our list of cold plunge and ice bath venues to find one near you. New to saunas altogether? Start with our first-timer’s guide to sauna etiquette.