How cold should an ice bath be? 50 to 59°F
How cold should an ice bath be? Start at 50 to 59°F. What Cleveland Clinic, Mayo Clinic and a review of nine trials say, and what colder water costs in ice.
For checking the water
All our tub picksThe short answer
50–59°F
That is 10 to 15°C. Start at the warm end for one to two minutes. Go below 50°F only once a session feels easy, and don’t go below 40°F at all.
For checking the water
All our tub picksHow cold should an ice bath be?
An ice bath, or cold plunge, should be between 50 and 59°F for most people. That range is where the medical advice for beginners and the trial evidence for sore muscles overlap, and it is colder than it sounds. Water at 59°F is enough to make you gasp.
We read three sources on cold plunge temperature. They agree on the water and disagree on the clock.
| Source | Water temperature | Time in the water |
|---|---|---|
| Cleveland Clinic, a sports medicine physician | 50–59°F for beginners. Never below 40°F | 1–2 minutes to start. 5 minutes at most |
| Mayo Clinic Health System, a sports medicine specialist | 50°F or colder | 30 seconds to a minute to start, working up to 5–10 minutes |
| Machado and others, 2016, a review of nine trials on muscle soreness | 52–59°F (11–15°C) gave the best results | 11–15 minutes gave the best results |
The times look far apart because the settings are. A trial puts a trained athlete in a tub with a researcher standing next to it. You are at home, possibly alone. Take your temperature from the range all three share, and your time limit from the most cautious source: five minutes.
Cold plunge temperature zones
- 59–50°F Where to start, and where the evidence is 1–2 minutes at first
- 50–45°F Once the first minute is easy Up to 5 minutes
- 45–40°F Experienced plungers only Shorter, not longer
- Below 40°F Too cold Cleveland Clinic says avoid it
The outer limits come from the sources above. The step at 45°F is ours, to show the way down.
Why colder isn’t better
Nothing we read shows that colder water does more for you. The review of nine trials found the best results for muscle soreness at 52 to 59°F, the warm end of what plungers call cold.
The risk does rise as the temperature falls. The American Heart Association reports a warning from the National Center for Cold Water Safety that sudden immersion in water under 60°F can kill in less than a minute. The cause is the cold shock response, a sudden jump in breathing, heart rate and blood pressure. An exercise scientist quoted by the American Heart Association puts the most dangerous window at the first ten seconds to a minute.
So 59°F is already inside the range where your body reacts hard. Dropping to 42°F buys a sharper shock and a shorter session, and no benefit anyone has measured.
What colder water costs in ice
Every degree below your tap temperature has to be paid for. On ice, the bill grows faster than the thermometer drops.
| Target temperature | Ice for 100 gallons |
|---|---|
| 55°F | 25 lb |
| 50°F | 51 lb |
| 45°F | 80 lb |
| 40°F | 110 lb |
Going from 55°F to 45°F takes more than three times the ice. Our guide to how much ice an ice bath needs has the figures for other tap temperatures and tub sizes. That is the practical case for settling in the low 50s. A chiller changes the sum, because it holds whatever number you set, but a lower setting still means it runs longer. Our pick of the best cold plunge chillers lists how cold each one goes. How we work figures like these out is on how we review.
Work down over four weeks
The cold shock response eases as your body gets used to cold water, so step down gradually. This plan stays inside Cleveland Clinic’s limits throughout.
- Week one, 59°F. One to two minutes. Breathe out slowly and let the first gasp pass.
- Week two, 55°F. Two minutes. Add a session if the first minute no longer feels like a fight.
- Week three, 52°F. Up to three minutes. Get out as soon as your hands stop working well.
- Week four, 50°F. Stay here. Most people never need to go lower.
Checking the temperature
Measure the water before you get in. Mayo Clinic gives the same advice, and it matters most with ice, because you can’t judge 48°F from 56°F by hand.
A floating thermometer is enough for a tub on ice. Stir the water first, since it is colder next to the ice than it is a foot away. With a chiller, check its display against a second thermometer once, then trust it.
Common questions
Is 60°F cold enough for a cold plunge?
Yes, for a start. Cleveland Clinic’s beginner range tops out at 59°F, and the safety warning the American Heart Association reports covers any water under 60°F. If a minute at 60°F feels hard, you are in the right place.
How cold should a cold plunge tub be for sore muscles?
Between 52 and 59°F. A 2016 review of nine trials found that range gave the best results for muscle soreness after exercise. If you lift for strength, Cleveland Clinic advises waiting, because cold water within four hours of strength training may hold back muscle gains.
Is 40°F too cold for an ice bath?
It is the floor. Cleveland Clinic says to avoid water below 40°F, and nothing we read shows a benefit from going that low.
What is 50 to 59°F in Celsius?
10 to 15°C. Most research on cold water immersion is published in Celsius, which is why the trial range reads as 11 to 15°C.
Do I need a chiller to reach 50°F?
No. From 60°F tap water, about 51 lb of ice brings 100 gallons down to 50°F. A chiller makes sense once you plunge often enough that buying ice becomes the bigger cost.