Diving into icy waters is an exhilarating experience that challenges one's sense of thermal comfort. Despite the chilling prospect, many individuals embrace this polar bear-like behavior for health benefits, as evidenced by the popularity of cold water immersion challenges among athletes and influencers.

Submerging oneself in frigid water is believed to alleviate post-exercise muscle pain, inflammation, and stress. However, is this practice all it's cracked up to be, or does it come with risks such as hypothermia? Let's explore the advantages and potential hazards of cold water immersion, also known as cold plunges or ice baths.

What Exactly is a Cold Plunge?

A 2022 review in the European Journal of Applied Physiology defines cryotherapy as a therapeutic approach that includes the use of cold water, ice, or air. Cold plunging, a form of cryotherapy, involves immersing oneself in cold water at various temperatures and durations. This exposure leads to a loss of body heat, a drop in internal temperature, and a change in blood circulation. Cold water immersion (CWI), synonymous with ice baths or cold plunges, has historical roots dating back to 3500 B.C., with Hippocrates being credited as a pioneer in the field of cryotherapy for his belief in the medicinal use of cold.

How Cold is Cold?

According to Dr. Raj Dasgupta, chief medical advisor for Sleep Advisor, the typical temperature range for cold water plunges is between 55 and 69 degrees Fahrenheit. The depth of immersion is a personal choice, with some individuals opting for full-body submersion and others choosing a partial immersion up to the neck or chest. Regardless of the method, the primary motivation for enduring the cold is to gain potential health benefits.

Benefits of Cold Plunges

Reducing Inflammation and Enhancing Immunity

Inflammation is a natural response to injury or infection, but chronic inflammation can lead to health issues such as heart disease. Cold temperatures may help reduce inflammation by affecting blood vessels. "Ice baths can constrict blood vessels and decrease blood flow to the affected areas. Once you exit the cold water, your body's natural response is to rush blood back to those areas, initiating the healing process," explains Dr. Dasgupta. A 2022 study in Biological Research for Nursing found significant pain reduction in individuals with gout arthritis, an inflammatory condition. Cold therapy reduces inflammation and interferes with the brain's perception of pain, similar to the numbing effect of a cold spray before an injection.

Increasing Circulation

Your circulatory system, consisting of the heart, capillaries, veins, and arteries, is responsible for blood flow throughout the body. "The theory is that the stress of cold water triggers the body to work hard to maintain its core temperature, which increases blood flow and circulation to aid in the recovery process," Dr. Dasgupta says.

Boosting Mood

A 2023 study published in Biology found that adults who immersed themselves in 68°F water for five minutes experienced increased alertness, pride, inspiration, and reduced distress and nervousness. Emotional conditions like anxiety and depression may be linked to low levels of neurotransmitters, which are essential for brain function. Cold exposure can trigger the release of neurotransmitters that regulate emotions and stress. "An increase in mood-regulating brain chemicals, such as dopamine, may account for the post-plunge 'high' some people feel," Dr. Dasgupta suggests.

Reducing Post-Workout Muscle Soreness

Many athletes use cold-water baths to prevent muscle soreness and stiffness and to improve recovery. A 2023 review in Sports Medicine found that participants who used CWI had significantly lower creatinine-kinase levels, markers of muscle damage and delayed onset muscle soreness, compared to those who used passive recovery. These effects were short-term, with lower water temperatures and shorter immersion times being more effective.

How to Perform a Cold Plunge and Duration

For beginners, it's recommended to start with cool water rather than ice-cold water. "Those new to ice baths should begin with 5 to 10 minutes in cool water and gradually increase the duration," advises Dr. Dasgupta. Studies have shown that short to medium immersion times, between 5 to 15 minutes, are effective. It's also important to stay hydrated and to take a hot shower or bath afterward to warm up.

Potential Risks

Hypothermia

Water can remove body heat 25 times faster than air, and hypothermia can occur in water temperatures below 70°F, according to the Centers for Disease Control and Prevention. Hypothermia can impair movement and cognitive skills, posing a significant risk.

Cold Shock and Drowning

Cold shock is an involuntary response to a sudden drop in skin temperature, often leading to an involuntary gasp and hyperventilation, which can result in water inhalation and drowning. This combination puts additional strain on the cardiovascular system.

Who Should Avoid Cold Plunges?

Individuals with Heart Conditions

Cold-water immersion can be particularly risky for those with pre-existing heart and cardiovascular conditions, as it can cause the heart to work harder and potentially lead to fatal outcomes.

Older Adults

As we age, our body's ability to maintain temperature decreases due to a reduction in subcutaneous fat. Hypothermia is a leading cause of death among older adults, and avoiding cold-water immersion is recommended.

The Bottom Line

While more research is needed to confirm the health effects of ice-water baths, they may offer benefits for healthy individuals. However, those with heart conditions and older adults should consult a healthcare provider before engaging in cold-water activities. If you decide to try CWI, pay close attention to your body's signals and exit the bath if you experience dizziness, lightheadedness, or any other discomfort.