The claim
“Cold exposure improves your sleep.”
Early. The overnight sleep data come from trained men after evening exercise, where one small study found fewer arousals after a cold bath and another found no change. No controlled trial has measured how a cold plunge affects sleep in people who aren't athletes.
Updated Sep 24, 2026 · 1 study reviewed
Some human data and a plausible mechanism. It needs better trials before anyone can lean on it.
People say it in places like these
Peter Attia's podcast
He pairs a cold plunge with his bedtime sauna and uses the routine partly to sleep better.
See an example ↗Wim Hof Method website
People who practice the method report better sleep.
See an example ↗
The research found this
An Australian study put 11 trained male cyclists through evening exercise with and without a cold-water immersion afterwards.Source 1 · Crossover trialEffect of Evening Postexercise Cold Water Immersion on Subsequent SleepRobey E, Dawson B, Halson S, et al.. Medicine & Science in Sports & Exercise, 2013.Read the paper ↗PubMed ↗ Overnight recordings found no difference in total sleep, sleep efficiency, time to fall asleep or sleep stages. Core temperature ran lower for a 90-minute window about 3.5 to 4.5 hours after exercise when the men had used cold water, and melatonin did not change.
A French trial had 12 well-trained runners do a simulated trail run around 6 p.m. and then sit for 10 minutes in 13.3°C water, either up to the hips or with the whole body and head under water.Source 2 · Crossover trialEffect of the Depth of Cold Water Immersion on Sleep Architecture and Recovery Among Well-Trained Male Endurance RunnersChauvineau M, Pasquier F, Guyot V, et al.. Frontiers in Sports and Active Living, 2021.Read the paper ↗PubMed ↗ Both immersions reduced arousals across the night compared with staying out of the water. Whole-body immersion also raised the share of slow-wave sleep in the first three hours and cut limb movements.
In an Australian heat-training study of 30 men, adding 15 minutes of cold water after each session had minimal effect on sleep measured with activity monitors and diaries.Source 3 · Randomized trialSleep quantity and quality during consecutive day heat training with the inclusion of cold-water immersion recoverySkein M, Wingfield G, Gale R, et al.. Journal of Thermal Biology, 2018.Read the paper ↗PubMed ↗ A 2025 meta-analysis still listed sleep among cold water's effects, and its evidence was that study's subjective quality rating of 3.6 against 3.1 on a 1–5 scale.Source 4 · Meta-analysisEffects of cold-water immersion on health and wellbeing: A systematic review and meta-analysisCain T, Brinsley J, Bennett H, et al.. PLOS ONE, 2025.Read the paper ↗PubMed ↗
Outside athletes the data are thin. Four people in the Dutch cold-shower trial reported insomnia they linked to evening cold showers.Source 5 · Randomized trialThe Effect of Cold Showering on Health and Work: A Randomized Controlled TrialBuijze GA, Sierevelt IN, van der Heijden BCJM, et al.. PLOS ONE, 2016.Read the paper ↗PubMed ↗ An uncontrolled Danish pilot in 13 psychiatric patients who swam in cold water twice a week reported sleep scores improving from 10.4 to 8.0 on a questionnaire where lower is better.Source 6 · Clinical trialCold water swimming as an add-on treatment for depression: a feasibility studyHjorth P, Rasmussen MRV. European Psychiatry, 2024.Read the paper ↗
The dial reads 58°H for four reasons
How the reading adds up
12 + 16 + 16 + 14 = 58°H
EvidenceWhat kind of evidence exists in people?
12/25Three small trials measured sleep after cold-water immersion in trained men who had just exercised, and the largest had 30 men.Source 1 · Crossover trialEffect of Evening Postexercise Cold Water Immersion on Subsequent SleepRobey E, Dawson B, Halson S, et al.. Medicine & Science in Sports & Exercise, 2013.Read the paper ↗PubMed ↗Source 2 · Crossover trialEffect of the Depth of Cold Water Immersion on Sleep Architecture and Recovery Among Well-Trained Male Endurance RunnersChauvineau M, Pasquier F, Guyot V, et al.. Frontiers in Sports and Active Living, 2021.Read the paper ↗PubMed ↗Source 3 · Randomized trialSleep quantity and quality during consecutive day heat training with the inclusion of cold-water immersion recoverySkein M, Wingfield G, Gale R, et al.. Journal of Thermal Biology, 2018.Read the paper ↗PubMed ↗
ConsistencyHas the finding held up?
16/25Overnight recordings in 11 cyclists found no change in any whole-night measure, while 12 runners had fewer arousals after a cold bath.Source 1 · Crossover trialEffect of Evening Postexercise Cold Water Immersion on Subsequent SleepRobey E, Dawson B, Halson S, et al.. Medicine & Science in Sports & Exercise, 2013.Read the paper ↗PubMed ↗Source 2 · Crossover trialEffect of the Depth of Cold Water Immersion on Sleep Architecture and Recovery Among Well-Trained Male Endurance RunnersChauvineau M, Pasquier F, Guyot V, et al.. Frontiers in Sports and Active Living, 2021.Read the paper ↗PubMed ↗ Activity monitors in a third trial showed minimal effect.Source 3 · Randomized trialSleep quantity and quality during consecutive day heat training with the inclusion of cold-water immersion recoverySkein M, Wingfield G, Gale R, et al.. Journal of Thermal Biology, 2018.Read the paper ↗PubMed ↗
MagnitudeDoes the claim match the size of the effect?
16/25The claim promises better sleep in general. The benefits measured were fewer arousals and more early deep sleep in one group of runners, and the meta-analysis result people cite rests on a single 1–5 rating from a study whose own authors reported minimal effect.Source 2 · Crossover trialEffect of the Depth of Cold Water Immersion on Sleep Architecture and Recovery Among Well-Trained Male Endurance RunnersChauvineau M, Pasquier F, Guyot V, et al.. Frontiers in Sports and Active Living, 2021.Read the paper ↗PubMed ↗Source 4 · Meta-analysisEffects of cold-water immersion on health and wellbeing: A systematic review and meta-analysisCain T, Brinsley J, Bennett H, et al.. PLOS ONE, 2025.Read the paper ↗PubMed ↗Source 3 · Randomized trialSleep quantity and quality during consecutive day heat training with the inclusion of cold-water immersion recoverySkein M, Wingfield G, Gale R, et al.. Journal of Thermal Biology, 2018.Read the paper ↗PubMed ↗
DoseDoes the studied protocol match how people use it?
14/25The trials used 10 to 15 minutes at 13–14°C in the evening after hard exercise.Source 2 · Crossover trialEffect of the Depth of Cold Water Immersion on Sleep Architecture and Recovery Among Well-Trained Male Endurance RunnersChauvineau M, Pasquier F, Guyot V, et al.. Frontiers in Sports and Active Living, 2021.Read the paper ↗PubMed ↗Source 3 · Randomized trialSleep quantity and quality during consecutive day heat training with the inclusion of cold-water immersion recoverySkein M, Wingfield G, Gale R, et al.. Journal of Thermal Biology, 2018.Read the paper ↗PubMed ↗ No trial has tested a morning plunge or a plunge without a workout.
The claim drifts from the data here
All the overnight data come from trained men who had exercised hard that evening.Source 1 · Crossover trialEffect of Evening Postexercise Cold Water Immersion on Subsequent SleepRobey E, Dawson B, Halson S, et al.. Medicine & Science in Sports & Exercise, 2013.Read the paper ↗PubMed ↗Source 2 · Crossover trialEffect of the Depth of Cold Water Immersion on Sleep Architecture and Recovery Among Well-Trained Male Endurance RunnersChauvineau M, Pasquier F, Guyot V, et al.. Frontiers in Sports and Active Living, 2021.Read the paper ↗PubMed ↗ They say nothing about a morning plunge by someone who didn't train.
The 2025 meta-analysis's abstract lists sleep among cold water's effects. That line rests on one subjective rating in one study, and the study's own abstract reports minimal effect on sleep.Source 4 · Meta-analysisEffects of cold-water immersion on health and wellbeing: A systematic review and meta-analysisCain T, Brinsley J, Bennett H, et al.. PLOS ONE, 2025.Read the paper ↗PubMed ↗Source 3 · Randomized trialSleep quantity and quality during consecutive day heat training with the inclusion of cold-water immersion recoverySkein M, Wingfield G, Gale R, et al.. Journal of Thermal Biology, 2018.Read the paper ↗PubMed ↗ Cold can also keep people awake, as the insomnia reports in the shower trial show.Source 5 · Randomized trialThe Effect of Cold Showering on Health and Work: A Randomized Controlled TrialBuijze GA, Sierevelt IN, van der Heijden BCJM, et al.. PLOS ONE, 2016.Read the paper ↗PubMed ↗
Put it to use
If you plunge in the evening, notice how you sleep, and move the plunge earlier if it keeps you awake. The trials give no reason to expect a large change either way.Source 1 · Crossover trialEffect of Evening Postexercise Cold Water Immersion on Subsequent SleepRobey E, Dawson B, Halson S, et al.. Medicine & Science in Sports & Exercise, 2013.Read the paper ↗PubMed ↗Source 5 · Randomized trialThe Effect of Cold Showering on Health and Work: A Randomized Controlled TrialBuijze GA, Sierevelt IN, van der Heijden BCJM, et al.. PLOS ONE, 2016.Read the paper ↗PubMed ↗
From our sister magazine
Sauna Monthly covers the wearables that track resting heart rate and HRV
If you want to see how plunging affects your own nights, a wearable gives you the data.
Sauna Monthly · Guide
A wearable shows the adaptation happening
Resting heart rate and HRV shift across a block of regular sauna weeks.
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A ring or strap shows what heat does to your heart rate
Sauna Monthly covers the wearables that track resting heart rate and HRV.
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People also ask
Does a cold plunge before bed help you sleep?
No trial has tested it in people who aren't athletes. In trained runners, 10 minutes at 13.3°C after an evening run reduced arousals overnight, while in trained cyclists evening cold water changed no whole-night sleep measure.Source 2 · Crossover trialEffect of the Depth of Cold Water Immersion on Sleep Architecture and Recovery Among Well-Trained Male Endurance RunnersChauvineau M, Pasquier F, Guyot V, et al.. Frontiers in Sports and Active Living, 2021.Read the paper ↗PubMed ↗Source 1 · Crossover trialEffect of Evening Postexercise Cold Water Immersion on Subsequent SleepRobey E, Dawson B, Halson S, et al.. Medicine & Science in Sports & Exercise, 2013.Read the paper ↗PubMed ↗
Can cold showers keep you awake?
Four people in a Dutch trial of 3,018 adults reported insomnia they linked to evening cold showers.Source 5 · Randomized trialThe Effect of Cold Showering on Health and Work: A Randomized Controlled TrialBuijze GA, Sierevelt IN, van der Heijden BCJM, et al.. PLOS ONE, 2016.Read the paper ↗PubMed ↗
Check these claims next
58°H
Early
“A sauna before bed helps you sleep better.”
In an online survey, 83.5% of sauna users said sauna helped their sleep, and warm baths before bed improve sleep in measured studies. No study has recorded sleep after a sauna with lab equipment or a wrist tracker.
34°H
Likely
“A cold plunge lifts your mood.”
People usually feel better right after a cold dip, and in the one randomized comparison of durations, five minutes lifted mood as much as twenty. None of the studies blinded people or used a placebo, so expectation can't be separated from the cold.
30°H
Likely
“Ice baths help you recover faster after exercise.”
Across dozens of small trials, cold water after hard exercise eased soreness and helped muscle power recover by the next day. The soreness benefit averaged about 0.3 points on a 0–10 scale in one meta-analysis, and the largest review found no faster recovery of strength.
We cited these sources
- 01Robey E, Dawson B, Halson S, Gregson W, King S, Goodman C, et al.. Effect of Evening Postexercise Cold Water Immersion on Subsequent Sleep. Medicine & Science in Sports & Exercise. 2013;45(7):1394-1402. doi:10.1249/MSS.0b013e318287f321 PMID 23377833
- 02Chauvineau M, Pasquier F, Guyot V, Aloulou A, Nedelec M. Effect of the Depth of Cold Water Immersion on Sleep Architecture and Recovery Among Well-Trained Male Endurance Runners. Frontiers in Sports and Active Living. 2021;3:659990. doi:10.3389/fspor.2021.659990 PMID 33870188
- 03Skein M, Wingfield G, Gale R, Washington TL, Minett GM. Sleep quantity and quality during consecutive day heat training with the inclusion of cold-water immersion recovery. Journal of Thermal Biology. 2018;74:63-70. doi:10.1016/j.jtherbio.2018.03.012 PMID 29801652
- 04Cain T, Brinsley J, Bennett H, Nelson M, Maher C, Singh B. Effects of cold-water immersion on health and wellbeing: A systematic review and meta-analysis. PLOS ONE. 2025;20(1):e0317615. doi:10.1371/journal.pone.0317615 PMID 39879231
- 05Buijze GA, Sierevelt IN, van der Heijden BCJM, Dijkgraaf MG, Frings-Dresen MHW. The Effect of Cold Showering on Health and Work: A Randomized Controlled Trial. PLOS ONE. 2016;11(9):e0161749. doi:10.1371/journal.pone.0161749 PMID 27631616
- 06Hjorth P, Rasmussen MRV. Cold water swimming as an add-on treatment for depression: a feasibility study. European Psychiatry. 2024;67(S1):S533-S534. doi:10.1192/j.eurpsy.2024.1109