Cold Plunges: What Science Reveals About Their Potential Benefits, Along with the Risks Involved

By Stan Martinez | Published on October 19, 2023
Reviewed By Gilmore Health | On: March 12, 2024

Taking a plunge into icy cold water may seem daunting, but it offers many potential health benefits if you can stand the discomfort – which not everyone enjoys. Cold water therapy was advocated by famous people like Charles Darwin and Florence Nightingale, and more recently, Wim Hof. The practice of cold water immersion has seen a surge in popularity in recent years, with people claiming benefits like improved circulation, reduced inflammation, and boosted immunity. But what does the science say about how cold plunges affect the body?

Ice Bath

A Physiological Response

When you immerse yourself in cold water, it triggers the mammalian dive reflex – an automatic physiological response to sudden cold water contact. This reflex causes peripheral blood vessels to constrict, redirecting blood flow to vital organs like the heart, lungs, and brain. As a result, cold water immersion can temporarily increase blood pressure and heart rate. The cold also triggers the release of stress hormones like adrenaline and noradrenaline, which increase alertness and focus. People who enjoy cold water plunges describe how it makes them feel invigorated.

Cold Shock

Another effect is called cold shock – the initial gasp and uncontrollable breathing upon first entering cold water. This is due to the sudden drop in skin temperature, which triggers hyperventilation. With regular cold exposure, the cold shock response becomes milder as the body acclimatizes. The initial deep breathing can also help lower blood pressure after the plunge is over.

Cytokines and Dopamine

There are several theories behind the long-term benefits of cold water immersion. One is that it stimulates the release of anti-inflammatory cytokines and dopamine. These help regulate the body’s immune response and may have anti-depressive effects. The cold is also thought to improve circulation by encouraging blood flow to the skin and accelerating post-exercise muscle recovery.

Boost Immunity

Some research supports certain benefits – like boosts in immunity and antioxidant activity – but overall, the data is limited. One study did find increased norepinephrine and dopamine levels after winter swimming in cold water for six weeks. A Dutch study also found that people who showered in cold water daily were 29% less likely to self-report an illness.

A Mood Booster

Some people claim it helps mental health disorders like depression, although this is difficult to prove, but there are studies that show cold water swimming leads to improved tolerance for stress and reductions in depression and anxiety. However, many studies are small or rely on self-reported data.

It’s Important to Be Aware of the Risks

There are some risks to consider as well. Sudden immersion in extremely cold water can cause cardiac arrest – however, this is very rare in healthy individuals. People with existing heart problems should avoid cold plunges altogether. There is also a risk of hypothermia if immersed too long. Most experts recommend gradually acclimating to cold water and being attentive to signs of hypothermia like shivering and loss of coordination. The linked article offers advice on how to decide on a water chiller if you want to try cold water therapy at home.

While more research is still needed, there are some scientific foundations for the purported benefits of cold water plunging. Starting with less extreme temperatures and short immersion times can help your body acclimatize safely. It is best to check with your doctor before plunging, especially if you have any health conditions or are new to cold exposure. With proper precautions, a plunge into frigid waters may provide an exhilarating boost to your health. But listen to your body’s limits, as the extreme cold is not for everyone.