How cold water immersion can improve mental health

As the new year approaches, some brave souls will be participating in the annual polar bear swim on January 1st. While many consider this a one-off thrill, an increasing number of cold-water worshippers continue this habit throughout the year, motivated by both physical and mental health benefits. Diving into fresh water is one of those experiences that sure feels invigorating, but recent research is backing up this boost in mood.

The Research Behind Cold Water Immersion

Studies have looked at the benefits of cold-water immersion on mental health. While researchers are quick to clarify that the scientific evidence is still limited, there are countless anecdotal accounts of cold-water immersion improving symptoms of anxiety, depression, and post-traumatic stress disorder.

In the UK, there is a club of cold-water swimmers who plunge year-round. On the West Coast of BC, there are a group of people who, for varying health reasons, submit themselves to a weekly cold swim and hold this ritual accountable for improvements in mood and overall health.

Hydrotherapy, the practice of applying or bathing in water of varying temperatures for therapeutic purposes, is not a new phenomenon. Use of hydrotherapy dates back to Hippocrates who believed cold water to be a treatment for lassitude.

Thomas Jefferson credited his morning cold water foot bath with ‘maintaining his good health.’ And in the 19th and early 20th century, the “water cure” was extolled by Sebastian Kneipp, a German forefather of natural medicine and fierce advocate of the benefits of hydrotherapy.

Now, modern, guru-type figures like the Iceman, Wim Hof are vocal proponents of cold-water immersion in conjunction with mindfulness and breathing techniques to regulate the nervous system.

But does it work? And if so, how does it work?

How Cold Water Immersion May Improve Your Mental Health

There are several compelling theories that might convince you to take the plunge to improve your mental health this January:

The Vagus Nerve

It’s long been implicated in mental health and stress-related conditions. This nerve connects the brain with all of our organs and turns off the sympathetic state or ‘fight-or-flight’ response we often have to our environment.

It turns out cold water exposure, even if it’s only splashing our face, activates the vagus nerve, slowing down our breathing and heart rate and switching us into a state referred to as parasympathetic mode, but more commonly known as ‘rest-and-digest’.

This is relevant to our mental health because research demonstrates that prolonged and chronic stress results in changes in the brain found in anxiety and depression.


We know cold water immersion increases production of mood-elevating hormones and neurotransmitters (beta-endorphins, noradrenaline and dopamine) that can improve symptoms of depression and anxiety by changing the chemistry in our body and brain. The rush we feel upon jumping in cold water is partly due to these chemicals communicating the experience to our brain.

Anti-inflammatory Properties

As we learn more about mental health, the model is shifting from simply a chemically imbalanced, brain-centric model to include other factors including systemic inflammation. Researchers are considering that cold-water immersion may act like a systemic ice pack, helping to reduce inflammatory markers that may contribute to depression and anxiety.

Sensory Input

We also have an extremely high concentration of cold receptors on the surface of our skin. When these nerve endings are simultaneously activated, the brain receives a huge influx of sensory information thought to have an antidepressant effect. Try to think about something other than the cold when you’re dipping into a glacial lake!

It’s possible this flood of sensory information from the skin to the brain acts as a pause button on the neurological processes that are part of depression and anxiety. When we’re immersed in cold water we may be interrupting certain neurological cycles contributing to mental health issues.

Stress Resilience

Plunging into the cold acts as a short-lived physiological stressor. It temporarily puts our system into sympathetic, survival mode. Now, while we don’t want to spend our entire lives in a stressed-out, sympathetic mode, brief and repeated exposure to physical stress may actually improve our overall stress response in a process called cross-adaptation.

Some researchers propose in practicing cold-water immersion regularly, individuals are developing a physical resilience to the stimulant of cold. By habituating to the cold, they are developing an adaptive response to one stress, which may translate into other, unrelated stress triggers.


Lastly, the psychosocial aspect of cold-water exposure can’t be underestimated. The sense of achievement, the commitment to oneself and to a ritual, and the opportunity for social connection when practicing regular cold-water immersion are all thought to play a role in improving mental health conditions.
While jumping in a cold lake, ocean, or river isn’t always possible, having a cold shower at home is!

As a general rule, start slow and acclimatise through repeated exposure in the form of short doses of cold-water exposure followed by warm clothes, warm drinks, and warming exercises. If you are pregnant, have cardiovascular issues or other health conditions, consult a doctor before taking the plunge.

If you’re struggling with mental health, reach out to your support network or contact a counsellor at Wellin5. In the event of a mental health emergency, call 9-1-1 or report to the emergency room as soon as possible.

Will you be making a fresh start this January? Join us and thousands of cold water enthusiasts at the 100th anniversary of the polar bear swim!

Dr. Nicole VanPoelgeest is a health writer and naturopathic doctor with a holistic approach to mental health. Learn more about her practice.