Freezing for Fitness? What Science Says About Cold-Water Immersion

Although ice-cold water exposure may seem extreme, some experts advocate the practice.

Liukov/Shutterstock

The first polar bear plunge occurred in Vancouver in 1920 by a group called the Polar Bear Club, and the tradition is still going strong.

Polar plunges are events where hardy souls take a dip in icy-cold ocean waters. The events are held yearly in various countries around the world. In the United States, they are often associated with fundraising for charitable organizations, such as the Special Olympics.

Cold plunges are also popular with athletes and wellness buffs, but does research support the hype? A recent meta-analysis took a comprehensive look and found that the practice offers a time-dependent benefit for stress, which has a bearing on mental and physical health. It also noted other benefits, including short-term help with inflammation and possibly sleep quality.

Story continues below advertisement

While earlier research on the mood and cognition effects of polar plunges is mixed, some conventional doctors join polar plunge gurus in recommending the practice for mental health. However, the plunges pose health risks for some, so people should check with their doctor before trying it.

Polar plunges are not for the faint of heart—even among those who are healthy—but the right technique can make them more tolerable.

Findings

The meta-analysis published in January, was conducted at the University of South Australia and published in PLOS One. It looked at data from 11 studies and 3,177 participants to determine the health effects of cold-water immersion in baths or showers. The authors defined cold-water immersion as immersing the body partially or fully in temperatures ranging from 50 to 59 degrees Fahrenheit for at least 30 seconds.

It is worth noting that while the authors confined their study to this temperature range, real-life experiences of cold-water immersion may involve temperatures that are colder or warmer. Since polar plunge events, in particular, are held in winter, they generally involve colder water.

“In this study, we noted a range of time-dependent results,” said coauthor Tara Cain in a press statement. “Firstly, we found that cold-water immersion could reduce stress levels, but for only about 12 hours post exposure.”

Story continues below advertisement

Cold-water immersion also produced short-term increases in inflammation. While this seems like a negative effect, athletes use ice baths regularly to decrease inflammation and muscle soreness after a workout, added coauthor Ben Singh in the press statement.

“The immediate spike in inflammation is the body’s reaction to the cold as a stressor. It helps the body adapt and recover and is similar to how exercise causes muscle damage before making muscles stronger, which is why athletes use it despite the short-term increase.”

Additionally, the team found some associations between cold-water immersion and higher-quality sleep, but because the data involved only men, they couldn’t determine whether the benefit would apply to women as well.

Despite many claims that the practice increases immune function, the evidence proved inconclusive. No significant changes in immune function were observed immediately or one hour after cold-water immersion.

Story continues below advertisement

No evidence was found that cold-water immersion improves mood, although improvements were observed in quality of life and sleep.

Because of the lack of long-term data and the small size of many of the clinical trials in the meta-analysis, the authors noted that more robust evidence is necessary to validate the benefits.

On a related note, cold-water exposure was associated with a 29 percent decrease in sickness absences in those who took cold showers, although there was no reduction in illness days. Cold showers were also linked to slightly higher quality of life scores.

Possible Mental Benefits

A 2023 study published in Biology involved 33 healthy participants who took a five-minute body bath in water at a temperature of 68 degrees Fahrenheit. Self-reported emotions indicated the participants felt more alert, active, inspired, attentive, and less nervous and distressed after the bath. The authors also measured brain connectivity and found that the boost in positive emotions—but not the reduction in negative emotions—was associated with the formation of connections within the brain involved in emotion, attention, and self-regulation.

In contrast, a 2021 systematic review published in the International Journal of Environmental Research and Public Health delivered negative results. After analyzing the effects of eight studies on cold air exposure and 10 on cold-water immersion, the authors found that the practices impaired cognitive performance even before the onset of accidental hypothermia (abnormally low body temperature). Impairments involved memory, attention, and processing speeds.

Doctors’ Views

Dr. Thompson Maesaka, a neurologist and co-owner of The Neural Connection, shared his view on polar plunges with The Epoch Times in an email.

Story continues below advertisement

“From the first plunge all the way to the 30th, you’ll feel an immediate improvement in alertness and mood. Many will also report improvements in motivation.”

To back his claims, he cited the study in Biology, noting that it offers evidence that regular plunges promote increased energy levels, motivation, and overall mood.

“The shock derived from cold water does improve the overall physique by improving the person’s mood,” Dr. Michael Chichak, a general practitioner and medical director at Medvidi, told The Epoch Times in an email.

“This is due to the increased release of endorphins and norepinephrine brought about by cold-water immersion. It greatly improves the physical and mental sharpness and relaxes the individual, which makes the person focused on all tasks throughout the day.”

Risks

The authors of the meta-analysis urged caution in cold-water immersion, as studies have not established its safety profile. It triggers short-term increases in blood pressure, heart rate, breathing rate, oxygen uptake, cortisol (the stress hormone), and norepinephrine. The long-term effects of these responses are not known, they wrote.

Story continues below advertisement

“Make sure you get screened for blood vessel issues and heart concerns before committing to a cold program,” Maesaka said.

“The sudden constriction of blood vessels can be problematic if you have an undiagnosed heart condition. If the blood vessel system is unable to handle that effect, the person may get lightheaded and faint. Getting screened and having supervision can reduce these risks.”

Paul Koepnick, founder of the Millioki Wellness Society, holds world records for extreme cold-water plunges. He told The Epoch Times in an email that in addition to heart-related risks, such as heart attacks, the practice can induce hypothermia, drowning, and potentially death.

“People with Raynaud’s disease will have a difficult time with the pain of the cold but using gloves and boots can ease symptoms,” Koepnick said.

Story continues below advertisement

Raynaud’s disease is a condition where small vessels that supply blood flow to the skin become narrower in response to cold and cause pain.

How to Polar Plunge

Polar plunge events are held in natural bodies of water, such as a lake or ocean. Yet to minimize the risk of accidental drowning and exposure to dangerously cold water, starting with a controlled environment like a bathtub is safer.

According to Koepnick, the following steps can help manage the risks of cold-water plunges:

1. Go slowly: Jumping in too fast can induce a shock response. Going slowly allows your body to regulate and adapt gradually.
2. Focus on long, slow exhales: Counteract the urge to gasp and hyperventilate by focusing on long, slow exhales, which send safety signals to your body. Then, keep breathing in a slow, controlled rhythm. The goal is to get yourself back to a normal breathing pattern.
3. Shift your reality: Recall a positive memory to help reframe your experience and make it more manageable.
4. Know when to stop: You only need 90 to 120 seconds to get the full effects. Never stay longer than five minutes. Finishing with a positive experience is key. Celebrate every attempt, even if it is only 10 seconds. Over time, the effects will compound if you continue practicing.

“I have taught over 20,000 hours of cold-water immersion with thousands of people all over the world and of all ages, and I have never had a negative health event when these protocols are followed,” Koepnick said.

He urges finding the temperature that works for you and gradually making the water colder. It should be cold enough to elicit a little fear and anxiety but safe enough that you could step out if it is too much.

As an ardent polar plunge enthusiast, Koepnick recommends the practice in glowing terms to everyone who doesn’t have a medical reason to abstain from it.

“Cold-water immersion, including cold plunges, is incredibly powerful and beneficial for your health,“ he said. ”It is one of the only practices that affects every single organ system in the human body down to the cellular level.”