Are cold showers good for you? What the science says

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(CNN) — You may have seen people jumping into frigid seas or stylish ice baths, claiming these dunks 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 applied for medical or therapeutic purposes in various ways. It can be done via ice, water or air, including cryosurgery for lesions, ice packs for swelling, or through ice baths for various purposes including exercise recovery or stress reduction.

There is a long history of people immersing themselves in cold water for the purported health benefits, tracing all the way back to ancient Greece — and thus a larger body of research on this type of cold therapy. In modern times, some people wonder if cold showers, a more accessible form of this trend, could also do the trick.

“The research is very, very thin as it pertains to cold showers itself,” said Dr. Corey Simon, an associate professor in the department of orthopedic surgery at Duke University and senior fellow at the Duke Aging Center. There are at least 100 studies, some of which are decades old or have methodological issues, and most also have low numbers of participants, who are usually healthy younger adults, Simon said.

But experts have ideas for why cold showers might work, based on what scientific and anecdotal evidence there is, he added.

Mental and heart health

Simon thinks most of the benefits of cold showers come from the psychological process of adapting to and overcoming a stressor — in this case, the chilly water.

“Folks don’t just go from zero to 60 in cold showers,” he said. “They have to work up to them usually, so there is the element of your body being able to control being in a stressful environment.”

This theory tracks with the results of some studies on cold showers. Participants who took showers with a water temperature of about 50 degrees Fahrenheit to 57.2 degrees Fahrenheit (10 degrees Celsius to 14 degrees Celsius) — for up to a minute daily for two weeks — reported lower stress levels than the control group, according to an October 2022 study published in the journal Current Psychology. The benefits were stronger when participants took their showers after doing a few rounds of a breathing technique that involved deep breathing, exhalation and breath holding.

Simon takes a cold shower once or twice per week, which he said has helped him become more mentally present in general since the practice forces him to process the “suffering.”

Cold showers may also improve mood and energy or mental alertness, which Dr. Rachelle Reed, an exercise physiologist in Athens, Georgia, has experienced, she said. “You sort of feel a little bit elated, and that is thought to be due at least in part to that increase in (the) neurotransmitters epinephrine, norepinephrine and dopamine.”

These psychological benefits may also be a primary reason why some people feel cold showers reduce their pain, for which psychological distress is a main predictor, Simon said.

During immersive cold therapy, the temperature shock can briefly stress the cardiovascular system, spiking blood pressure, heart rate and breathing rate, experts said. But this hyperactivity can lead to improved blood flow since the body needs to work to return to its normal state and warm up, Reed said. Cold showers could theoretically produce the same effect to some extent.

That said, people who have cardiovascular issues, circulatory problems, sensation issues — such as Raynaud’s disease or neuropathy — or diabetes should not try cold showers without speaking to a doctor first, experts said. The same goes for those who are pregnant, have recently had surgery, or are under the influence of alcohol or drugs, Reed said.

People have died from trying cold therapy, Simon said, so this disclaimer is serious and should not be ignored.

Supporting immunity

Cold showers may also help support the immune system. In a May 2014 study, the authors tested whether the immune systems 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 via injection, the study participants who had used the wellness techniques had fewer symptoms. Those participants also produced more anti-inflammatory chemicals and less inflammatory proteins in response to the infection.

But Simon isn’t sure this result is wholly positive, since recent research has started to suggest decreasing the inflammatory response to temporary illness might prolong or prevent recovery, he said. Chronic inflammation, not acute inflammation, is the bigger problem, Simon said. The Dutch study also doesn’t reflect the individual effectiveness of the three techniques: meditation, deep breathing and cold showers.

However, a September 2016 study based in the Netherlands found people who spent 30 to 90 seconds taking a cold shower experienced a 29% reduction in the amount of time absent from work due to sickness. There have also been anecdotal reports of getting sick less often while taking cold showers.

Cold showers could be beneficial in regard to fitness as a way to alleviate muscle soreness — but not right after a resistance training workout, Reed said.

“The latest evidence suggests that you would not want to disrupt the inflammation process that comes after lifting,” Reed said, which causes “the muscles to get stronger and larger and more efficient over time.”

Reed recommended using cold therapy only on days off from lifting. Additionally, cold showers may temporarily increase metabolism but haven’t been linked to weight loss.

Taking a cold shower

If you want to try taking cold showers and have been cleared by your doctor, start small, experts said.

Studies tend to employ cold showers in the range of 50 degrees Fahrenheit to 60 degrees Fahrenheit (10 degrees Celsius to 15.5 degrees Celsius), but a thermometer isn’t required, said Simon, who doesn’t use a thermometer and still experiences benefits — though he acknowledges this is anecdotal.

Quickly going from hot to cold could be too shocking, so ease from lukewarm water into cold, Simon suggested.

Fifteen to 30 seconds of cold exposure is good to begin with, Reed said. After that, try adding 15 seconds or so every few weeks.

As you build your tolerance level, box breathing can help you feel calm in the shower; resist holding your breath for too long, she added. That involves inhaling for four counts, holding for four counts, exhaling for four counts and holding for four counts.

Pay attention to your body’s feedback and any cues that you should remove yourself from the cold, Reed said.

Simon and Reed can’t definitively say taking cold showers are a surefire way to improve overall health, but they do think that in a stressful world, the practice can be a good addition to a baseline level of health already supported by the basics: diet, hydration, physical activity and sleep.

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