**The Chilling Truth: Exploring the Mental Health Benefits and Risks of Cold-Water Immersion**

Dr. Mark Harper recalls his first cold-water swim in the south of England 20 years ago. It was August, but the initial jolt from the plunge took his breath away. The shock to his system lasted a minute or two until he was “recombobulated and able to think about something other than the cold,” Harper says.

A surprise sensation soon replaced his discomfort. “I remember getting out of the water the first time and feeling so good,” Harper, an anesthesiologist who has since researched the potential risks and rewards of taking a nippy dunk, shared. “I wasn’t expecting that.”

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### A Historical Perspective on Cold-Water Immersion

Claims about the benefits of cold-water immersion date back centuries. Thomas Jefferson, the principal author of the Declaration of Independence and the third American president, wrote toward the end of his life about using a cold foot bath daily for 60 years. He also owned a book published in 1706 on the history of cold-water bathing.

While evidence is building around the positive health effects of swimming in chilly water, bathing in ice, or taking cold showers, scientific confirmation is still lacking. However, Harper, who became a regular cold-water swimmer after his initiation, said there are strong signs that people can derive mental health benefits from the activity. He specifically mentioned a positive effect on depression and general well-being.

“For now, we have a very strong base, but not hard evidence, that cold-water immersion is effective for mental health,” Harper told The Associated Press.

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### Boosting Mental Health Through Cold Water

Harper said his own early experiences with cold-water swimming piqued his professional curiosity. As a physician, he wondered if the brief bodily shock had clinical uses for treating depression.

He cited the biological phenomenon of hormesis, in which a stressor introduced at a low dose creates a positive response. For example, muscles and bones under stress—such as during weight-bearing exercise—respond by strengthening and growing.

Harper acknowledged that the positive effects he’s observed may be partially due to the placebo effect, where people report benefits simply because they believe a treatment is effective. In the case of cold-water immersion, benefits may also come from social interactions, the exercise itself, or the accomplishment of meeting a challenge, which boosts self-confidence.

“Personally, I think it’s all of those things, and the cold has an additive effect,” Harper said. “I think we have a good physiological basis for that. The basic science tells us the cold has a very strong effect on the body.”

He added, “What we’re talking about is an intervention that produces beneficial effects on mental health. So in a way, it doesn’t matter which aspect is generating the positive effects.”

Harper cited a common reaction among first-timers who take the plunge: “The fact that I’ve done this means I can do anything.” He described cold-water swimming as “quite a confidence builder,” and noted that people stick with it because they enjoy it so much.

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### Know the Risks When You Start

Dr. Mike Tipton, a physiologist at the University of Portsmouth in England who has studied extreme environments, co-authored a paper with Harper titled *Cold Water Immersion: Kill or Cure*. The title reflects the dual nature of cold water—it can be either harmful or therapeutic depending on the circumstances.

“Like other environmental constituents such as pressure, heat, and oxygen, cold water can be either good or bad, threat or treatment,” they wrote after reviewing the research available at the time.

One clear finding: the activity presents dangers. Deaths from cold-water immersion are not uncommon. The shock of frigid water can cause people to hyperventilate and drown.

However, Tipton told The Associated Press that risks can be managed with common sense and precautions.

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### How Cold, How Long?

You don’t need to go to extremes to gain potential benefits. Entering water at a temperature of 15 to 20 degrees Celsius (59 to 68°F) and staying for only a few minutes is sufficient.

“If the water is colder than that, you may get more benefit—but limit your exposure,” Tipton explained. “If you ask me what protocol you would follow if you thought this was going to be doing you good, I wouldn’t go in water much below 12°C (54°F), and I wouldn’t stay in for much more than two minutes.”

Both Tipton and Harper said that any benefits from cold-water immersion come from the body’s cold-shock response: the sudden drop in skin temperature, the release of stress hormones, the release of endorphins, and the anti-inflammatory effect.

Tipton cautioned against long spells in an ice bath. “Sitting in water for as long as I can fills me with horror,” he said. “This could destroy small nerves and blood vessels in extremities and could result in amputation the same way frostbite can.”

Harper, who has swum for as long as four hours in open water, advised vigilance. “People think it’s got to be super cold, super long, and the longer the better,” he said, “and that’s wrong.”

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### Be Safe: Remember, You’re a Tropical Animal

Tipton emphasized that he’s not trying to be the “fun police” but suggested caution and a medical screening before taking the plunge. Humans are considered “tropical animals” who need to adapt to the cold and are better suited to warm conditions.

A human’s resting body temperature is about 36.5 to 37.5 degrees Celsius (97.7 to 99.5°F). Because of that, cold-water immersion is stressful and carries risks for both the cardiovascular and respiratory systems—not to mention the risk of drowning.

“We don’t want to stop people doing it,” Tipton said, “but we want to make sure they do it in a way that maximizes the benefits and minimizes the risks.”

He recommended swimming in life-guarded areas or with experienced outdoor swimmers. Knowing the body of water is essential; hazards might include tides, temperature, depth, and pollution.

“Understand that taking a tropical animal and putting it in cold water is probably the greatest stress that most people will experience in their life,” Tipton said. He suggested entering the water gradually rather than jumping in.

“Be sensible about it,” he advised. “Incremental is the key.”

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**Cold-water immersion can offer promising mental health benefits if approached thoughtfully and safely. For those interested, start slow, stay aware, and listen to your body.**
https://www.phillytrib.com/news/health/cold-water-immersion-may-offer-health-benefits—-and-also-presents-risks/article_952a3db4-2e82-4319-b7de-3204f140454b.html