The claim
“Cold showers mean you get sick less.”
Unsettled. In a trial of 3,018 Dutch adults, people who finished their showers cold took 29% fewer sick days off work. They didn't report significantly fewer days of illness, and most people in every group missed no work at all.
Updated Sep 24, 2026 · 2 studies 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
Ben Greenfield's blog
A cold finish to your shower means 29% less sickness.
Gary Brecka's website
Cold water may raise your white blood cell count.
See an example ↗Cold plunge brands
Cold stimulates your white blood cells, and one study substantially lowered upper respiratory infections.
The research found this
The evidence comes from a Dutch trial called the Cool Challenge. In December 2014 researchers signed up 3,018 working adults aged 18 to 65 who didn't already take cold showers. Chance decided whether each person would finish a normal warm shower with 30 to 90 seconds of cold water or keep showering as usual.Source 1 · 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 ↗ The cold groups did it every day through January 2015 and then as they liked for 60 more days. All the results, sick days included, came from web surveys that people filled in themselves.
Over 90 days, the cold showerers took 29% fewer days off work for sickness than the usual showerers.Source 1 · 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 ↗ In statistical terms that's a rate ratio of 0.71, and the plausible range runs from 0.56 to 0.89. The trial also counted days of illness. For those the ratio was 0.89, with a range of 0.77 to 1.01, and the difference was not significant. The typical (median) person in every group took no sick days and reported two days of illness.
Thirty seconds of cold cut absence as much as 90 seconds did.Source 1 · 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 ↗ Regular exercise went with a bigger drop in absence (a rate ratio of 0.65) than the cold showers did, and the authors' model projected a 54% cut for people who did both. About 79% of people stuck with the cold for the full 30 days, and 64% kept going afterwards.
The other studies of cold and colds are small. In a UK trial of 180 adults, 13 of 90 people who had their feet chilled reported a cold within four to five days, against 5 of the 90 whose feet weren't chilled.Source 2 · Randomized trialAcute cooling of the feet and the onset of common cold symptomsJohnson C, Eccles R. Family Practice, 2005.Read the paper ↗PubMed ↗ Another UK study followed cold-water swimmers for 13 weeks, and their rate of colds did not differ significantly from the rates in their non-swimming partners or in pool swimmers.Source 3 · Cohort studyHabitual cold-water swimming and upper respiratory tract infectionCollier N, Lomax M, Harper M, et al.. Rhinology journal, 2021.Read the paper ↗PubMed ↗
The dial reads 50°H for four reasons
How the reading adds up
14 + 16 + 18 + 2 = 50°H
EvidenceWhat kind of human evidence exists?
14/25One large randomized trial compared cold showers with usual showers. People knew which group they were in and reported every outcome themselves by web survey.Source 1 · 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 ↗ The trial also tallied days of illness directly, and that number did not fall significantly.
ConsistencyHave other studies found the same thing?
16/25All the shower evidence comes from that one trial. Studies of cold-water swimmers disagree. Over 13 weeks, a UK study found no significant difference in colds across four groups that included the swimmers' own partners, and a Polish survey linked plunging twice a week to shorter colds.Source 3 · Cohort studyHabitual cold-water swimming and upper respiratory tract infectionCollier N, Lomax M, Harper M, et al.. Rhinology journal, 2021.Read the paper ↗PubMed ↗Source 4 · Cross-sectional studyInverted “u-shaped” association of cold-water immersion frequency with mental health and upper respiratory tract infection: a cross-sectional studyCzarnecki J, Mokros Ł. Brain, Behavior, & Immunity - Health, 2025.Read the paper ↗PubMed ↗
MagnitudeDoes the claim match the size of the effect?
18/25The claim takes a 29% relative drop in days off work and calls it less sickness. Median absence was zero days in every group, and the number of days people spent ill did not differ significantly.Source 1 · 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 ↗
DoseDoes the studied dose match how people use it?
2/25The trial tested the habit as people do it at home. Participants finished a normal warm shower with 30 to 90 seconds at the coldest setting every day for 30 days. The tap water averaged 10–12°C, and the longest cold finish did no better than the shortest.Source 1 · 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 ↗
The claim drifts from the data here
The trial counted days off work and days of illness, and the two can move separately. Absence fell while illness showed no significant change. That is the pattern you would expect if people felt ill about as often and went to work anyway, and self-reported data can't separate it from people getting sick less.Source 1 · 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 ↗
Recruitment rode on Wim Hof's popularity, and the promotional material listed the benefits people might expect.Source 1 · 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 ↗ Participants knew whether they were taking cold showers and scored their own outcomes, so expectation had room to shape the answers. The trial also ran through an unusually long flu season in 2014–15.
Put it to use
Finish your shower cold if you like how it feels. For cutting sick days, 30 seconds did as much as 90 in the trial, and regular exercise went with a bigger drop than the cold showers did.Source 1 · 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 hot-and-cold routines and the plunge tubs people buy for them
Sauna Monthly · Guide
Run the Nordic hot and cold cycle at home
Sauna Monthly covers contrast sessions and the choice between an ice barrel and a chiller.
Sauna Monthly · Guide
These cold plunge tubs are worth buying
Sauna Monthly picks its favorites and names the spec that decides between them.
People also ask
How long should a cold shower be?
Thirty seconds was enough in the Dutch trial, where it cut sick days off work as much as 60 or 90 seconds did.Source 1 · 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 ↗ No length of cold shower has been shown to change how often people fall ill.
Do cold showers boost your immune system?
The one trial of cold showers found no significant drop in days of illness. It collected everything by web survey and took no blood samples, so it can't tell you anything about immune cells.Source 1 · 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 ↗ The immune studies people cite tested the Wim Hof Method, and there the breathing did most of the work.Source 5 · Randomized trialThe Effects of Cold Exposure Training and a Breathing Exercise on the Inflammatory Response in Humans: A Pilot StudyZwaag J, Naaktgeboren R, van Herwaarden AE, et al.. Psychosomatic Medicine, 2022.Read the paper ↗PubMed ↗
Are cold showers bad for you?
The most common complaint in the Dutch trial was a cold feeling that lingered afterwards. It showed up in the body for 196 people and in the hands or feet for 257, and three of those 257 had the circulation disorder Raynaud's. Four people had insomnia they linked to evening cold showers.Source 1 · 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 ↗ The trial excluded people with severe heart or lung disease.
Check these claims next
56°H
Unsettled
“The Wim Hof Method lets you control your immune system.”
Men trained in the method had a smaller inflammatory response to an injected bacterial toxin, and the breathing did most of the work. In a later trial, cold training alone left that response unchanged, and no study has tracked whether practitioners get sick less.
62°H
Stretched
“Cold plunges reduce inflammation in your body.”
A 2025 pooled analysis of 11 studies found that inflammation markers rose right after cold water, and the two studies behind that result both had people lift weights first. When people took regular dips for weeks, blood markers of inflammation stayed flat or rose slightly.
54°H
Unsettled
“Regular sauna use means you catch fewer colds.”
One 50-person trial from 1990 found fewer colds in regular sauna users, and in the last three of its six months they had about half as many. It stands alone, and the other support comes from a Finnish study that linked frequent sauna use to less pneumonia.
We cited these sources
- 01Buijze 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
- 02Johnson C, Eccles R. Acute cooling of the feet and the onset of common cold symptoms. Family Practice. 2005;22(6):608-613. doi:10.1093/fampra/cmi072 PMID 16286463
- 03Collier N, Lomax M, Harper M, Tipton M, Massey H. Habitual cold-water swimming and upper respiratory tract infection. Rhinology journal. 2021;59(5):485-487. doi:10.4193/Rhin21.068 PMID 34428265
- 04Czarnecki J, Mokros Ł. Inverted “u-shaped” association of cold-water immersion frequency with mental health and upper respiratory tract infection: a cross-sectional study. Brain, Behavior, & Immunity - Health. 2025;49:101118. doi:10.1016/j.bbih.2025.101118 PMID 41127868
- 05Zwaag J, Naaktgeboren R, van Herwaarden AE, Pickkers P, Kox M. The Effects of Cold Exposure Training and a Breathing Exercise on the Inflammatory Response in Humans: A Pilot Study. Psychosomatic Medicine. 2022;84(4):457-467. doi:10.1097/PSY.0000000000001065 PMID 35213875
- 06Cain 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