Ice bath
In sports therapy, an ice bath, or sometimes cold-water immersion or cold therapy, is a training regimen usually following a period of intense exercise in which a substantial part of a human body is immersed in a bath of ice or ice-water for a limited duration. While it is becoming increasingly popular and accepted among athletes in a variety of sports, the method is controversial, with a risk of hypothermia, with the possibility of shock leading to sudden death. Many athletes have used cold water immersion after an intense exercise workout in the belief that it  speeds up bodily recovery; however, the internal physical processes are not well understood and remain elusive. Evidence supporting cold water immersion as part of an athletic training regimen remains inconclusive, with some studies suggesting a mild benefit such as reducing muscle damage and discomfort and alleviating delayed onset muscle soreness, with other studies suggesting that cold water immersion may slow muscle growth and interfere with an overall training regimen. Techniques. Bath. It is done by standing or sitting in a bucket or bath of icy water. One writer advised: "don't overdo it." Wearing rubberized "dive booties" on the feet  (to protect toes) as well as rubber briefs to warm the midsection have been recommended. Champion weightlifter Karyn Marshall, who won the world women's weightlifting championship in 1987, described what it was like to take an ice bath after a day of competition at the CrossFit Games in 2011 in Los Angeles: One report suggested that if ice water is circulating, it's even colder such that the water will be colder than measured by a thermometer, and that athletes should avoid overexposure. Physical therapist Nikki Kimball explained a way to make the bath more endurable: Ice bath only  versus contrast bath therapy. Some athletes use a technique known as contrast water therapy or contrast bath therapy, in which cold water and warmer water are alternated. One method of doing this was to have two tubs––one cold (10–15 degrees Celsius) and another hot (37–40 degrees Celsius) ––and to do one minute in the cold tub followed by two minutes in a hot tub, and to repeat this procedure three times. Temperature and timing. The temperature can vary, but is usually in the range of 50–59 degrees Fahrenheit or between 10 and 15 degrees Celsius. Some athletes wear booties to  keep their toes warm or rubberized coverings around their midsection while immersed. Some drink a warm beverage such as tea. One report suggested that "ten minutes immersed in 15 degree Celsius water" was sufficient. Accounts vary about how long to be immersed and how often to do them. One adviser suggested that an athlete should take ten two-minute ice bath treatments over a two-week period. One account suggested immersion times should be between ten and twenty minutes. Another suggested that immersion run from five to ten minutes, and sometimes to twenty minutes. There were no sources advocating being  immersed for longer than twenty minutes. Ice baths versus cold baths. Several sources suggest that cold baths (60–75 degrees Fahrenheit, 15.5-22.8°C) were preferable to ice baths. Physiotherapist Tony Wilson of the University of Southampton said that extremely cold temperatures were unnecessary and a "cold bath" would be just as effective as an ice bath. Another agreed that a mere cold bath is preferable to ice baths which are "unnecessary." A third report suggested that cool water (60–75 degrees Fahrenheit, 15.5-22.8°C) was just as good as water at a lower temperature (54–60 degrees Fahrenheit, 12.2 -15.5°C) and that eight to ten minutes should be sufficient time, and warned against exceeding ten minutes. Effectiveness. After exercise, there is some evidence that taking an ice bath may reduce delayed onset muscle soreness and perceptions of fatigue, but no good evidence of any other benefit. Chronic use of the ice bath may be beneficial for athletes who are in high volume training periods. Research has shown that ice baths four times per week in a congested training schedule of professional rugby players reduced muscle soreness while attenuating the decline in jump performance compared to those who  didn't ice bath. Safety. There is agreement in the medical and scientific communities that ice baths can pose serious risks to health. Risks include hypothermia, shock and the possibility of sudden cardiac death. History. Marathon runner Paula Radcliffe won the 10,000m event at the 2002 European championships and attributed her victory to the use of ice baths. She reportedly said "It's absolute agony, and I dread it, but it allows my body to recover so much more quickly." She reported taking ice baths before racing and preferred her pre-race bath temperature to be "very cold." After  the Radcliffe comment, the technique has grown in popularity. It is gaining in popularity among athletes, such that some athletes "swear by it" but other accounts suggest it may be a fad. It has been used by athletes such as A. J. Soares and Olympic swimmer Michael Phelps as well as other celebrity endorsers and is getting to become "common practice" among athletes from different sports, including American football, association football (soccer), long distance running, rugby, tennis, volleyball, and other sports. There was a report that sports equipment manufacturers are considering different designs for ice baths. In the summer of  2014, as a fundraising method, the nonprofit ALS Association, which raises money for research and public awareness of amyotrophic lateral sclerosis or ALS, also known as Lou Gehrig's disease, began the Ice Bucket Challenge which involved donors filming themselves and challenging other donors to participate and then being doused with a bucket of ice cold water; as a fundraising effort, it raised $16 million over a 22-day period. There are indications that ice baths may be gaining popularity with groups outside sports, such as dance. The "Pittsburgh Post-Gazette" reported that some Radio City Rockettes, a precision  dance company performing in New York City, use ice baths after a long day of performing as a way to "unwind" and cope with "aches and pains." One report suggested that entertainer Madonna used ice baths after her performances. And there are indications that use of ice baths is spreading to amateur sports, such as high school football. Explorer and athlete Fiann Paul is known for using ice baths as part of his training routine. Ice baths are a part of a broader phenomenon known as cryotherapy—the Greek word "cryo" (κρυο) means "cold"—which describes a variety of treatments when  cold temperatures are used therapeutically. Cryotherapy includes procedures where a person is placed in a room with "cold, dry air at temperatures as low as −135 °C" for short periods of time, and which has been used in hospitals in Poland as well as a center in London to treat not only muscular ailments, but psychological problems such as depression. Basketball player Manny Harris reportedly used a Cryon-X machine featuring extreme low temperatures around minus 166 degrees Fahrenheit, but used it with wet socks resulting in a serious freezer burn. Occasionally ice baths have been an ill-advised  treatment of fever in young children, but that doctors were counseled not to use this technique because of the risk of hypothermia. Ice baths have been suggested as a way to prevent muscle soreness after shoveling snow. In addition, there have been instances of ice bathing as an extreme bodily test by persons vying for an endurance record, such as Dutch "Iceman" Wim Hof, and Chinese record-holders Chen Kecai and Jin Songhao. According to reports, doctors and scientists are studying how these people can spend an hour and a half submerged in an ice bath, and survive; for almost  all humans, such tasks are impossible.