You may have seen people jumping into frigid seas or bathing in stylish ice baths, claiming these treatments are good for heart health, muscle recovery, stress and more.
This practice is known as cold water immersion, a type of cryotherapy or cold therapy — which can be used for medical or therapeutic purposes in a variety of ways, CNN reported.
Therapy can be done through ice, water, or air, including cryosurgery for lesions, ice packs for swelling, or ice baths for a variety of purposes, including exercise recovery or stress reduction.
There is a long history of cold water immersion for its supposed health benefits, dating back to Ancient Greece.
"There's very little research on cold showers themselves," said Dr. Corey Simon, an associate professor in the Department of Orthopedic Surgery at Duke University and a senior fellow at the Duke Center on Aging.
"There are at least 100 studies, some of which are decades old or have methodological problems, and most of them also have small numbers of participants who are generally healthy younger people," Simon said.
However, experts have ideas about why cold showers may work based on scientific and anecdotal evidence.
Simon believes that most of the benefits of cold showers come from the psychological process of adapting to and overcoming a stressor—in this case, cold water.
This theory matches the results of some studies on cold showers. According to an October 2022 study published in the journal Current Psychology, participants who took showers with water temperatures of about 10°C to 14°C — for up to one minute a day for two weeks — reported lower stress levels from the control group. The benefits were stronger when participants took a shower after doing several rounds of a breathing technique that involves deep inhalation, exhalation and breath retention.
Simon takes a cold shower once or twice a week, which he says has helped him become more resilient in general, as the practice forces him to process the "suffering."
"Cold showers can also improve mood and energy or mental alertness," said Dr. Rachel Reed, an exercise physiologist in Athens, Georgia.
"You seem to feel a little high, and that's thought to be at least in part due to an increase in the neurotransmitters epinephrine, norepinephrine, and dopamine," Reed says.
"These psychological benefits may also be the main reason why some people find that cold showers reduce their pain, for which psychological distress is a major predictor," Simon said.
During cold water immersion, the temperature shock can cause short-term stress on the cardiovascular system by increasing blood pressure, heart rate and breathing rate, experts say.
"But this hyperactivity can lead to improved circulation as the body has to work to return to normal and warm up," Reid said.
Cold showers could theoretically produce the same effect to some degree. However, people who have cardiovascular problems, circulation problems, sensory problems - such as Raynaud's disease or neuropathy - or diabetes should not try cold showers without consulting a doctor. The same applies to pregnant women, people who have recently undergone surgery or are under the influence of alcohol or drugs.
According to Simon, people have died trying cold therapy, so this warning is serious and should not be ignored.
Cold showers can also support the immune system. In a May 2014 study, the authors tested whether the immune system of a small group of Dutch men could be improved by practicing meditation, deep breathing and cold showers for 10 days. When the authors administered a bacterial infection by injection, study participants who used the healing techniques had fewer symptoms.
These participants also produced more anti-inflammatory chemicals and less inflammatory proteins in response to the infection.
Simon isn't sure this result is entirely positive, as he says recent research has begun to suggest that reducing the inflammatory response in a temporary illness may prolong or prevent recovery. The Dutch study also did not reflect the individual effectiveness of the three techniques: meditation, deep breathing and cold showers.
However, a September 2016 study conducted in the Netherlands found that people who spent 30 to 90 seconds in a cold shower reduced the amount of time they were absent from work due to illness by 29%. There are also unconfirmed reports of less frequent illness when taking a cold shower.
"Cold showers could be beneficial in terms of fitness as a way to relieve muscle soreness -- but not immediately after strength training," Reed said.
"Recent evidence suggests that you wouldn't want to disrupt the inflammatory process that occurs after lifting weights. This process causes the muscles to become stronger, bigger and more functional over time," she added.
Reid recommends using cold therapy only on non-weight-lifting days. Also, cold showers can temporarily increase metabolism, but are not associated with weight loss.
If you want to try taking cold showers and have been cleared by your doctor, start small, experts advise.
"Studies typically use cold showers in the 10 to 15.5°C range, but no thermometer is needed," said Simon, who doesn't use a thermometer and still experiences benefits.
Going from hot to cold water quickly can be too shocking, so go from lukewarm to cold water gradually, suggests the expert.
“15 to 30 seconds of exposure to cold water is good to start with. Then try adding about 15 seconds every few weeks," Reid recommended.
Simon and Reid can't say definitively that taking a cold shower is a surefire way to improve overall health, but they think that in a stressful world, this practice can be a good addition to the basic level of health already supported by basic factors: diet, hydration, physical activity and sleep. | BGNES
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