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. Ice baths exist as a practice outside the sports and exercise world as well. They have earlier roots of being used to combat extreme heat exposure in certain cultures. For instance, the Maya of Yucatan utilised the practice of “ice baths [and] ice-water baths” as a “treatment of heatstroke”  This population categorizes the objects and processes in their lives that are related to health as “hot” and “cold" types and are always trying to balance the two. In this context, the necessity and statistics of ice bathing are no longer relevant, as the practise is rather a “behavioural adaptation” for these peoples 

Despite the physical benefits of ice baths being seen as not worth the risks, there are many who believe that the practice is incredibly beneficial to one’s mental health. “It shocks your body and forces you to go into fight or flight mode,”  says an individual who took up the practice as a mechanism to cope with his depression. He believes that ice bathing has been a saviour of his life and has not experienced any negative risks associated with the practise. Thus, ice bathing is indeed not a necessity, yet can have extreme positive impacts on some and must not be overlooked as a mechanism for improving one’s mental health. 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 () 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 () was just as good as water at a lower temperature () 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. However, a number of studies find that cold water immersion impairs muscle hypertrophy and other adaptive responses to exercise. There is a phenomenon in Norway where people will alternate between using a sauna and ice bathing, which has been found to have positive health effects due to the social and community aspect of this practice. A qualitative interview study found that all interviewees that practiced this method of alternating between extreme temperatures in the urban areas of Norway saw sauna and ice baths as sociable places. This social aspect was mostly seen as “health- enhancing”, specifically for aging residents, though some identified this socialising as a disturbance. The fieldwork found that it was common for those that practiced sauna and ice bathing in Norway to report positive health benefits due to a sense of achievement in withstanding these extreme temperatures and many reported feelings of pleasure and positive mental state after taking part. Most interviewees reported positive experiences that aligned with ‘hedonic’ and ‘eudaimonic’ perceptions of well-being; terms explored by psychologists Ryan and Deci. While most of the perceptions of this practice were positive, it was noted that the quality of the water in some areas, as well as a lack of accessibility to the ice bathing, lead to more negative experiences, leaving some individuals excluded from the practice. 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. Ice baths began to become extremely popular after being discussed extensively by Joe Rogan and his universe of scientist and comedians such as Dr. Andrew Huberman (Stanford) and Aubury Marcus (Onnit). Ice bath verse Cryotherapy 
Ice baths, an activity within the practice of cryotherapy, has been predominately utilised for multiple decades for therapeutic purposes, typically for exercise recovery for athletes, and more recently for perceived mental health benefits, such as the alleviation of symptoms of mental health problems such as depression. Cryotherapy can be tracked “as far back as the Egyptians in 3000 BCE” as a wound treatment 

Cryotherapy can be dated back to ancient Greece, its first mention in an ancient Egyptian medical text ‘Edwin Smith Papyrus’ that is believed to date to around 3500 BCE, and furthermore through Hippocrates’s theory of the four humours. Although, when applying a historical perspective,cold-water immersion was used first as a form of socialisation and relaxation, before its physiological and psychological benefits were noted. The main medical treatments that Ancient Greeks employed the use of cold-water immersion for were fever, as the cold was thought to counteract the body’s heat, and for pain relief. The use of cold-water immersion for medical treatments for physiological symptoms continued until the late 1950s. In fact, it was not utilised for post-exercise recovery until the 1960s, by D H Clarke. However, the use of cold-water immersion for post-exercise recovery and treatment is by far the most popular and well-known use of the technique, despite being the most recent. See also
 Cryotherapy
 Dousing
 Ice bucket challenge
 Polar bear plunge
 Winter swimming

References

Physical therapy
Hydrotherapy
Experimental medical treatments
Athletic training