is "walrus" good or bad for you?

In the largest systematic review and meta-analysis to date (published in PLOS ONE), experts analysed data from 11 studies involving 3,177 people to find out exactly how cold water (approximately 10 to 15 °C) affects the body.

Key findings

• Stress reduction
  For approximately 12 hours after exposure to cold water, people experienced a reduction in stress levels.
• Sleep quality
  In some cases, men who regularly practised cold immersion reported more restful sleep. However, there is not yet enough data for female groups.
• Quality of life
  Participants who took cold showers (20, 60 or 90 seconds) reported a slight increase in general well-being and life satisfaction. After three months, this effect became less pronounced.
• Temporary spike in inflammation
  Paradoxically, contact with ice water produces a short-term spike in inflammation - a natural "stress" response of the body. In athletes, such a surge helps trigger recovery mechanisms, but people with chronic illnesses should be cautious.

According to Tara Kane, author of the study, many people use cold treatments in the hope of boosting their immune system or improving their mood, but there is little scientific evidence to support this. But there is evidence of short-term decreased absenteeism at work and reduced feelings of fatigue in cold showers.

Researchers emphasise that the effect of "walrus" largely depends on the time of exposure and the state of health of a particular person. As a rule, it is recommended to start with minimal intervals (30 seconds) and gradually increase the duration. However, there are as yet no clear official guidelines on the optimal frequency and length of such treatments.

Dr Ben Singh, who was involved in the study, reminds us that more long-term studies involving different age and social groups are needed to establish which categories of people can benefit most from cold dipping and when it is safe to do so.

Source: T. Cain et al, "Effects of cold-water immersion on health and wellbeing: A systematic review and meta-analysis", PLOS ONE (2025). DOI: 10.1371/journal.pone.0317615