How long should you cold plunge?

Ask ten regulars how long they stay in and you'll get ten answers, from "one breath" to "until I can't feel my feet". The honest answer depends on the water temperature, how used to cold you are, and why you're doing it. Here's how to work out your number.

Time by temperature

These are cautious rules of thumb rather than research findings. There's no study that sets a safe time for each temperature, because body size, body fat, wind and moving water all change how fast you cool. If you're not sure how cold the water is, read what temperature a cold plunge should be first.

The first minute

Whatever your target, the first minute is about breathing. Cold water triggers a gasp and fast, shallow breathing, the cold shock response. The RNLI says it passes in under a minute. Professor Mike Tipton, a cold water researcher at the University of Portsmouth, puts it at a minute to 90 seconds.

So a 30-second dip is mostly spent in the shock phase. That's fine for a beginner. Once you can stay past it, you'll notice your breathing settle and the water feel less brutal. That calmer phase is what most regulars are after.

Where "11 minutes a week" comes from

You'll often see 11 minutes of cold a week presented as the minimum dose for benefits. It comes from a 2021 study in Cell Reports Medicine, led by Susanna Søberg at the University of Copenhagen.

The study recruited eight young, healthy men who winter-swam and used saunas 2–3 times a week, and compared them with eight men who didn't. The researchers chilled them in the lab and measured brown fat and heat production. The winter swimmers were better at producing heat when cold.

The 11 minutes is a line in the table describing the swimmers' habits: about 2.6 swims a week, a couple of dips each time, about 1.4 minutes per dip. Their weekly sauna time came to 57 minutes. Nobody tested whether 11 minutes is better than 5 or 20, and the authors were clear they couldn't say winter swimming caused the differences. It's a reasonable description of a moderate habit. It isn't a proven threshold.

Longer dips for sore muscles

Sports research uses longer, milder immersions. A 2016 meta-analysis in Sports Medicine found the best results for muscle soreness at 11–15 °C (52–59 °F) for 11–15 minutes. The benefit over rest was small. If that's your goal, think "cool and longer", not "icy and longer", and see contrast therapy for the hot-cold version.

How long until it gets dangerous

Cold water safety courses often teach the 1-10-1 principle, developed by Canadian physiologist Gordon Giesbrecht:

• 1 minute of cold shock, when the gasping is worst.
• About 10 minutes of useful movement before your arms and legs get too cold to swim or grip properly.
• Around 1 hour before hypothermia makes you lose consciousness. Even in icy water, it takes at least 30 minutes for hypothermia to set in.

Hypothermia means your core temperature has fallen below 35 °C (95 °F). Giesbrecht's point is that most cold water deaths happen long before that, in the first two stages: a gasp underwater, or hands too numb to hold on. Treat the timings as rough. Thin people cool faster than people with more body fat.

You'll also keep cooling for a while after you get out, known as afterdrop. That's why shivering often starts on the jetty, not in the water.

Signs it is time to get out

• Your hands are numb or clumsy, or you can't make a fist.
• You're shivering hard or your teeth are chattering.
• Your breathing won't settle after the first minute or two.
• You feel confused or sleepy.
• You can't speak normally.

Feeling great is not a reason to stay longer. The buzz kicks in early, and you get it from a short dip as much as a long one.

Building up

1. Start short. 30 seconds to a minute, focusing on slow breaths out.
2. Add a little each time. 15–30 seconds per session is plenty.
3. Hold steady as it gets colder. When the sea cools in autumn, keep your time the same or cut it.
4. Warm up gently afterwards. Dry off, dress in layers and move around, or go back into the sauna. Our guide to sauna then cold plunge covers the full routine.

Who should be careful

• Heart conditions or high blood pressure. Cold shock puts sudden strain on the heart. Ask your doctor first.
• Open water. Never alone, always close to a ladder or shore, and know the conditions.
• Alcohol. Don't plunge after drinking.
• Pregnancy, Raynaud's or cold sensitivity. Check with a doctor or midwife.

This guide is general information, not medical advice.

Where to plunge

For what the research says about the benefits, see cold plunge benefits. Some places to try a timed dip:

Stu Brattøra

Trondheim · Fjord dips all year

KOK Aker Brygge

Oslo · Sauna boats on the fjord

Hellasgården Bastu

Stockholm · Lake bathing all year

Frequently asked questions