Cold Showers Were Linked to Fewer Sick Days. But Do They Really Keep You Healthier?

People who regularly took cold showers reported fewer sick days, but scientists aren't sure why.

The first few seconds of a cold shower can be absolutely brutal. Your breath catches and every instinct tells you to reach for the hot tap.

But a series of experiments in Switzerland suggests there might be a payoff for enduring the shiver: fewer days spent feeling sick. And if it helps, you get used to it, so it’s not a brutal ordeal every time.

Across three studies involving 719 adults, regular cold-shower takers reported 26 percent fewer days feeling ill and 31 percent fewer days off work because of sickness than people who mostly took warm showers. They also reported slightly better psychological well-being.

The study’s results, described in a new doctoral dissertation from the University of Basel, could point to an inexpensive habit that could have unexpected benefits for your health, while also cutting energy use and household bills.

What Happens When You Shower Cold for 12 Weeks?

Psychologist Lena Glaser and colleagues combined data from three trials conducted between 2019 and 2024. Participants were healthy adults aged 18 to 65, none of whom already regularly took cold showers.

The researchers also wanted to know whether there was any potential psychological crutch that could help people overcome their initial resistance to cold showers.

In one trial, participants watched 30-second motivational videos once a month. The researchers tested four different messages. Some emphasized personal benefits, encouraging people to think of cold showers as a brief daily exercise or an investment in their health. Others appealed to the more environmentally conscious, framing the habit as a way to save carbon emissions or help fight climate change.

Another trial took a more hands-on approach. Participants received five weekly emails containing videos and written exercises designed to build self-efficacy — essentially, confidence in their ability to persist with an uncomfortable habit.

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But neither strategy worked particularly well. Apparently having a talking head screaming at you YOU CAN DOOOO IT didn’t move the needle too much. The confidence-building program performed even worse: only 14 percent of participants receiving the training met the study’s adherence target, compared with 47 percent in the trial’s control group.

The researchers suspect that structured encouragement may sometimes backfire because a personal challenge could start feeling like an obligation, undermining the very motivation that keeps people going.

Researchers checked shower habits weekly and asked participants about illness and sick leave each month over 12 weeks. Those instructed to shower cold were asked to use the coldest available setting, with the research protocols specifying two to five minutes of whole-body exposure.

For the analysis, the researchers classified participants as regular cold-shower users if they took cold showers at least 70 percent of the time. Compared with those who showered cold less frequently or not at all, regular users reported 26 percent fewer days feeling ill and 31 percent fewer days off work because of sickness.

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But feeling sick less often doesn’t necessarily mean feeling healthier overall. When participants rated their general physical well-being and skin health in separate questionnaires, the researchers found no statistically significant improvements. Cold-shower users did, however, report modest improvements in psychological well-being and energy levels.

As one might expect, many volunteers abandoned the cold-shower habit early, particularly during the first fortnight. In a companion analysis of two trials, only 37 percent completed the full 12-week regimen. But among those who stuck to cold showers at least 70 percent of the time, up to 90 percent reported taking cold showers in any given week.

“That suggests people gradually get used to it,” Glaser said.

Do Cold Showers Actually Prevent Illness?

Previously, in a 2016 Dutch trial involving more than 3,000 people, volunteers who finished their warm showers with 30 to 90 seconds of cold water reported 29 percent less sickness absence. Yet they did not report significantly fewer days feeling ill. Perhaps the showers helped them feel capable of working when sick, rather than stopping illness outright. What’s more, people who persevere with an unpleasant routine may differ from those who stop in ways that also influence their health. If you’re the kind of person that does cold showers every day, and sticks to this routine, perhaps you truly are built different in ways that can’t apply to the general population.

Could cold water stimulate the immune system? Possibly. Another 2024 trial involving 60 adults found changes in some immune markers after repeated cold showers, but did not establish that participants caught fewer infections.

Meanwhile, a 2025 review of cold-water research found the evidence for improved immune function inconclusive. Another review published in September 2026 concluded that evidence for psychological benefits also remains too weak to establish reliable effects.

A Health Habit, or a Climate Habit?

Heating less water saves energy. The researchers estimated that participants avoided about 15 kilograms of carbon dioxide emissions each over 12 weeks, roughly the emissions from driving 100 kilometers.

“Taking a cold shower isn’t exactly pleasant, but it’s a small change to make. After all, we shower anyway,” Glaser said.

Still, cold showers are not for everyone. The trials excluded people with certain conditions, including serious cardiovascular disease and Raynaud’s phenomenon. Sudden cold exposure can strain the cardiovascular system, so people with a history of health problems should consult a clinician before trying it.

For otherwise healthy people who want to experiment, Glaser recommends lowering the temperature gradually rather than treating the coldest setting as a test of willpower.