By yourNEWS Media Newsroom
Researchers at Switzerland’s University of Basel have found that people who regularly take cold showers report substantially fewer sick days and work absences than those who shower with warm water, according to findings released Oct. 29. The study identified a 31% reduction in illness-related work absences and a 26% reduction in reported illness days among participants who adopted the cold-water routine.
The University of Basel announced the findings following research conducted by psychologist Lena Glaser as part of her doctoral dissertation examining how people develop healthier and more environmentally sustainable habits.
The research combined data from three controlled experiments involving 719 adults between 18 and 65 years old. Participants were generally healthy and had no established habit of taking cold showers before entering the study.
Over 12 weeks, participants in the intervention groups were instructed to shower with water as cold as their household plumbing allowed, while those in the comparison group continued their usual showering routines.
The results showed that participants who regularly exposed themselves to cold water reported 31% fewer days absent from work because of illness compared with the control group. They also experienced 26% fewer days during which they felt sick.
The findings suggest that regular cold-water exposure may influence both the frequency of reported illness and its effects on daily activities, although the research did not establish precisely how cold showers might produce those benefits.
According to a Nov. 5 analysis published by ScienceAlert, the investigators also identified modest improvements in psychological well-being among people who maintained the cold-shower routine. Participants reported feeling more alert, refreshed and mentally energized after their showers.
The researchers observed signs of improved physical well-being, although those changes did not reach statistical significance.
One finding involved the participants’ ability to adapt to cold exposure. The initial two weeks produced substantial dropout rates, indicating that many people found the sudden change in water temperature uncomfortable or difficult to maintain.
However, withdrawals declined as the experiments continued, suggesting that those who persisted gradually adapted to the experience.
“That suggests people gradually get used to it,” Glaser said.
Among participants who maintained the routine at least 70% of the time, weekly adherence rates ranged from approximately 77% to 90%, depending on the experiment.
The researchers also found that participants frequently described an immediate feeling of alertness and satisfaction after completing their showers. Some reported that overcoming their reluctance to enter cold water increased their sense of accomplishment.
Glaser’s research examined those psychological responses as part of a broader investigation into what motivates people to adopt beneficial behaviors.
Cold showers offered a useful example because they require little specialized equipment, can be incorporated into established daily routines and may reduce energy consumption by limiting hot-water use.
The study’s findings are consistent with earlier research examining the relationship between cold exposure and health.
A 2016 randomized controlled trial published in PLOS ONE examined 3,018 adults in the Netherlands who were assigned to finish their showers with 30, 60 or 90 seconds of cold water or continue showering normally.
Participants followed their assigned routines for 30 consecutive days, with researchers monitoring illness and work attendance during a 90-day study period.
That trial found a 29% reduction in self-reported sickness absence among people assigned to cold showers compared with the control group. However, researchers did not observe a statistically significant overall reduction in the number of days participants felt ill.
The distinction raised questions about whether cold showers reduced illness itself or influenced participants’ perceived symptoms, resilience or willingness to continue normal activities while feeling unwell.
The newer Swiss research reported reductions in both work absences and illness days, providing additional evidence that regular cold exposure may have broader effects than previously observed.
In their research paper, Glaser and her colleagues stated, “Our pooled analysis shows a clear reduction in both illness days and sickness absence, suggesting a robust effect that translates directly into improved work attendance and reduced productivity loss.”
The researchers also suggested that changes in participants’ subjective well-being may help explain the findings.
“Our findings on improved well-being suggest that cold showers might offer [an] effective method for improving mental and physical health, thereby potentially reducing the risk factors that lead to sickness absence in the first place,” they wrote.
Scientists have previously investigated whether repeated exposure to cold water influences immune function, circulation, stress responses and inflammation.
Cold exposure can temporarily activate the sympathetic nervous system, which regulates involuntary responses to physical stress. It can also alter levels of certain stress-related hormones and influence cardiovascular activity.
Some studies have identified changes in immune system markers following cold-water exposure, raising the possibility that repeated exposure could affect the body’s response to infections.
However, the Swiss experiments did not directly investigate biological mechanisms or establish that improved immune function caused the reported reductions in illness.
The findings also carry important limitations. The research relied on self-reported illness and work absences, rather than independently verified medical diagnoses or employment records.
Although the underlying experiments used randomized designs, the pooled analysis grouped participants according to their actual showering behavior, potentially introducing differences unrelated to water temperature.
The findings were reported in Glaser’s doctoral dissertation, and the accompanying research paper had been submitted to the Journal of Health Psychology but had not undergone peer review at the time of the announcement.
The study also did not determine whether participants continued taking cold showers after the 12-week experimental period or whether any benefits persisted over longer periods.
Despite those limitations, researchers believe the results justify further investigation into cold showers as an inexpensive method of potentially improving well-being and reducing workplace absenteeism.
Glaser recommended a gradual approach for people interested in trying the practice, rather than abruptly exposing themselves to extremely cold water.
“The water doesn’t have to be equally cold every day,” she said. “It’s important to listen to your body and pay attention to how you feel. But sometimes it’s worth pushing yourself a little.”
Cold exposure can produce sudden cardiovascular and respiratory responses, particularly in people with certain heart or circulatory conditions. Individuals with relevant medical concerns should seek professional guidance before attempting intense cold-water exposure.
The University of Basel findings add to growing scientific interest in how everyday environmental exposures may influence health. While additional research is needed to confirm the results and identify the mechanisms involved, the study suggests that regular cold showers may be associated with fewer illness-related absences and improvements in psychological well-being.
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