Recent research suggests taking a dip in very cold water for several hours a week is good for our health. Researchers from the University of Central Lancashire in the U.K. looked into the benefits of cold-water immersion therapy. They found it could have positive effects on our cognition, sleep quality, and overall well-being. The researchers studied the effects on the health of 13 people. The participants were dunked in 10ºC water for 10 minutes, three times a week, for four weeks. Study author Dr Robert Allan said the cold-water therapy could "help with a number of positive physiological and psychological changes linked to improvements in overall general health and well-being".

Cold-water immersion has been used in various fields for its curative and healing benefits. For many decades, ice baths have helped to speed the recovery of athletes following intense, energy-sapping performances. Dr Allan said his findings also showed a positive impact on sleep. He said: "Two weeks of regular therapeutic cold-water immersion improved subjective sleep, with fewer sleep disturbances." Subjecting the body to cold water for health purposes is already a common practice. At the New Year, people take a plunge in icy seas and lakes. In Japan, bathers refresh their bodies by alternating dips in hot and cold baths in a tradition known as toto-no-u.