The claim
“Cold exposure improves your sleep.”
Unsettled. The overnight sleep studies tested trained men after evening exercise. One small study found fewer brief awakenings 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
A little human data and a plausible mechanism support it. Better trials have to come before anyone relies 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, time to fall asleep, sleep stages or sleep efficiency (the share of time in bed spent asleep). When the men had used cold water, their core temperature ran lower for a 90-minute stretch after bedtime, and the sleep hormone 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 kinds of immersion reduced brief awakenings across the night compared with staying out of the water. Going fully under also raised the share of deep, slow-wave sleep in the first three hours, and the runners moved their limbs less.
In an Australian heat-training study of 30 men, activity monitors and sleep diaries showed that adding 15 minutes of cold water after each session had minimal effect on sleep.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 pooled analysis still listed sleep among cold water's effects. Its evidence was one subjective rating from that same study, where people scored their sleep quality on a 1–5 scale at 3.6 with cold water and 3.1 without.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 ↗ A small Danish study with no comparison group followed 13 psychiatric patients who swam in cold water twice a week. Their sleep scores improved 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 human evidence exists?
12/25Three small trials measured sleep in trained men who got into cold water after exercise, 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 ↗
ConsistencyHave other studies found the same thing?
16/25Overnight recordings in 11 cyclists found no change in any whole-night measure, while 12 runners had fewer brief awakenings 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 ↗ In a third trial, activity monitors 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 measured benefits were fewer brief awakenings and more early deep sleep in one group of runners, and the pooled result people cite comes from one 1–5 rating in 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 dose 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 ↗ Morning plunges and plunges without a workout haven't been tested.
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 ↗ Those results can't tell you what a morning plunge does for someone who skipped the workout.
The abstract of the 2025 pooled analysis lists sleep among cold water's effects. That line traces back to one subjective rating in one study, and that 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 cost sleep, and a few people in the shower trial blamed evening cold showers for insomnia.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
The trials give no reason to expect a large change either way, so if you plunge in the evening, notice how you sleep and move the plunge earlier if it keeps you awake.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 your resting heart rate and heart rate variability
If you want to see how plunging affects your own nights, a wearable gives you the data.
Sauna Monthly · Guide
A wearable can show your body adapting to heat
Resting heart rate and heart rate variability shift over a few weeks of regular saunas.
Sauna Monthly · Shop
A ring or strap shows what heat does to your heart rate
Sauna Monthly covers the wearables that track your resting pulse and heart rate variability.
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Oura Ring 4
People also ask
Does a cold plunge before bed help you sleep?
That hasn't been tested in people who aren't athletes. In trained runners, 10 minutes at 13.3°C after an evening run cut brief awakenings overnight, and in trained cyclists evening cold water changed no whole-night measure of sleep.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?
A handful of people say so. In a Dutch trial of 3,018 adults, four 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
Unsettled
“A sauna before bed helps you sleep better.”
In an online survey, 83.5% of sauna users said sauna helped their sleep, and measured sleep improves after a warm bath before bed. Sleep after a sauna has yet to be recorded 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 trial that compared durations, five minutes lifted mood as much as twenty. The studies had no placebo and people knew what they were getting, 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 pooled analysis, and the largest review found strength came back no faster.
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