Ice baths and cold showers have become popular, and many people say cold water is good for health. Some of these claims may be true, but the evidence is still limited.
In May 2025, researchers shared preliminary results at the European Congress on Obesity. Their study suggests that regular cold exposure from cooling vests might help people lose body fat. "This is one of the first studies looking at the impact of cold exposure over a prolonged period of time," said study co-author Mariëtte Boon, a doctor at Leiden University Medical Center in the Netherlands.
The study included 47 overweight adults in the Netherlands. About half of them wore a cooling vest and a waist wrap for two hours every morning for six weeks. The other half, the control group, did not. On average, the cold group lost 2 pounds, while the control group gained 1.3 pounds.
Most of the difference came from a drop in body fat. Lean mass, such as muscle and bone, stayed about the same. This matters because people who lose weight often lose muscle too.
Why might cold help? Study co-author Helen Budge, a biologist at the University of Nottingham in England, explained that "daily cold exposure activates brown fat, which uses body fat stores to produce heat." The team is now testing whether a 90-second cold shower each morning could be enough.
Still, the study was small and short, and the effect was modest. In a 2022 paper, Norwegian biologist James Mercer, who was not part of the new study, and his colleagues reviewed 104 studies on getting into cold water. They found it might bring benefits, but more well-controlled studies were needed. A separate 2025 study by other researchers found that people who sat in cold water for 30 minutes ate more afterward than people who sat in room-temperature water. That extra food might replace the calories they had burned.
"Ultimately, it's still going to come down to energy expenditure. Calories in, calories out," said Andrew Tracey, a fitness director at a health magazine.