Sitting in cold water for several hours a week is good for our health. Researchers studied the effects of cold-water immersion therapy. They found it could benefit our cognition, sleep, and well-being. Thirteen test participants sat in 10ºC water for 10 minutes, three times a week, for four weeks. The study said the cold water could "help with a number of positive physiological and psychological changes linked to improvements in overall general health".

Cold-water therapy is used in many areas. For decades, ice baths have helped with the recovery of athletes after high-energy performances. The researcher said therapeutic cold-water immersion led to "fewer sleep disturbances". Taking cold-water baths for health is already a common practice. At the New Year, people worldwide swim in icy seas and lakes. In Japan, bathers refresh their bodies by dipping in and out of hot and cold baths.