'a cold water plunge can wake us up better than a cup of coffee'

the physical benefits of immersing your body in cold water have been known for centuries, but the greatest advantage might have more to do with your mind.

by emma jones

published apr 12, 2022

last updated feb 17, 2023

6 minute read

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6 minute read

join the conversation

cold water immersion: the benefits of swimming in frigid temperatures

emma jones (top centre) and others take part in a lake ontario cold water plunge at toronto’s humber bay park, thursday april 7, 2022. [peter j thompson] [national post/emma jones for healthing]

there are few things as tranquil as a beach on a cold day. the water, which in the warmer months is packed with sunbathers looking to cool off and teenagers daring each other to go deeper, flows without interruption. its colour taking on a deeper blue from the lack of sunlight on a grey, windy day. it’s not entirely surprising, then, that some have started to gravitate to the water on the days that send most scrambling inside. the benefits of cold water immersion have been touted since the ancient greeks, who embraced the new-found concept of thermalism. modern readers are likely to be at least somewhat familiar with wim hof, the dutch “iceman” who holds the guinness world record for the farthest swim under ice and offers training services to help others develop the same mental fortitude.

proponents of cold water immersion claim the practice increases mental clarity and productivity, supports the immune system and aids in fat burning and cardiovascular health — highly attractive claims for the overstressed and overworked, bracing for the return of the low-rise jean.

trying cold water immersion for ourselves

journalists were invited by yeti to take part in an unbounded experience, a toronto-based company that leads groups in dipping themselves in frigid water.

the event kicked off with a quick workout to warm up, then a breathing practice where participants were encouraged to alternate between taking quick, deep breaths followed by completely exhaling all the air from our lungs. after we got the hang of it, we were then told to get into our bathing suits and get ready to head into the 2°c waters of lake ontario.

the uncomfortable ‘i want to get out’ feeling is part of the experience, and is tied to one of the key benefits of submerging your body in very cold water, explains lisa kricfalusi, one of the co-founders of unbounded.

“when your body goes into water that is less than 10 degrees — zero to four is the sweet spot, really — you go through a fight or flight response,” says kricfalusi. “norepinephrine is flooded into your bloodstream … that constricts your blood vessels [bringing] warm blood to your core to protect your vital organs.”

this fight or flight response is caused by an activation of the sympathetic nervous system, explains stephen cheung, ph.d, a professor of kinesiology at brock university researching the body’s response to extreme temperatures. (cheung wasn’t part of the unbounded experience.)

when someone first immerses themselves into frigid waters, their skin temperature rapidly drops, telling the body to react now in order to get back to a safer environment.

“you can think of it as the gas pedal … when your skin temperature drops very quickly like that, you are essentially slamming on the gas pedal,” says cheung. demanding your body go from 0 to 100 causes both your heart rate and breathing to increase and causes a release of adrenaline (norepinephrine). this response is one of the reasons a cold water plunge can wake us up better than a cup of coffee, and may have other benefits to the immune system.

does cold water therapy impact the immune system?

while we gravitate toward warm, comfortable options, research indicates that introducing our bodies to controlled stressors — like a short, intense bout of exercise or a dip in icy temperatures — can have surprising health benefits. what exactly these benefits are, however, and how long they last, are still up for debate

one small study on the wim hof method, the most widely known cold-water immersion method that includes a meditation and breathing practice, found that participants may have a better immune response. twenty-four people were instructed to either go about their daily lives (control group) or were trained for 10 days in meditation, breathing techniques and cold water exposure (trained group). after the 10 days, all participants were given an infusion of escherichia coli endotoxin — a type of bacteria that causes diarrhea and abdominal cramping. the participants in the trained group showed fewer flu-like symptoms and got over their fever more quickly than the control group. blood tests also showed that the trained group had a greater level of anti-inflammatory mediators and, as a result, a lower inflammatory response to the endotoxin.

much of the results in this study were connected not just to exposure to cold water, but also to the breathing techniques that are followed in the wim hof method. the study authors noted that doing this breathing method just before being exposed to the endotoxin correlated with “profoundly increased” adrenaline levels, which may have influenced the anti-inflammatory response and mediated the flu-like symptoms.

lisa kricfalusi takes part in a lake ontario cold water plunge at toronto’s humber bay park, thursday april 7, 2022. [peter j thompson] [national post/emma jones for healthing]

what do the experts say about taking an icy plunge?

kelli king a doctoral candidate of human kinetics at the university of ottawa explains that while the small studies conducted on cold water therapy show promise, there still hasn’t been enough research to come to a conclusion.

“there are a lot of different systems that are involved during cold exposure that can be beneficial to health,” says king. for example, inflammation control — which is sometimes why elite athletes will take an ice bath to help with recovery between training sessions.

other claims, like increased weight loss, still aren’t fully understood, she explains. while some studies have shown that cold exposure converts fat to a form that is arguably easier for the body to burn, these studies were conducted in rats which have different physiologies than humans. shivering after getting out of the cold water could be one of the key ways the body burns more fat during the experience — but what effect does that have if someone gets out of the water and immediately changes into warmer clothing? scientists aren’t sure.

both cheung and king are also still waiting on long-term studies that may show the effects of regular plunges over the course of years.

“do they have, 10 years later, more protection against heart disease? do they have lower blood pressure? do they have any of those things? we don’t really know,” says cheung.

risks of cold water immersion

as with any activity that puts stress on your body, there are some risks that should be taken into account before taking the plunge.

cold water causes the blood vessels in your extremities to constrict, which concentrates the warm blood in your torso, protecting organs like the heart and lungs, explains cheung. this causes an increase in blood pressure and can be stressful to the heart — dangerous for anyone already experiencing high blood pressure or heart conditions.

surprisingly, what one would think is the most obvious risk — hypothermia — doesn’t present too much of a concern, as long as a swimmer doesn’t spend more than a few minutes in the water and has a plan to dry off and warm up immediately after getting out, he says. however, there is a serious risk of drowning as the cold water can cause muscles to seize up, making it difficult to swim to shore in case of emergency.

for this reason, it is never safe to do a cold plunge on your own. always make sure a friend is close by with a plan to get you out of the water and contact emergency services if needed.

just breathe

physical questions aside, putting our body through such a stressful circumstance could, ironically, be the way to a more tranquil life.

once the water hits waist height, it quickly becomes hard to inhale forcing swimmers to push back against the panic. learning to breathe through the anxiety-inducing feeling of not being able to get enough air could be one of the key takeaways from the training as we return to the stressful, non-stop demands of the digital era.

“building resilience is really incredibly easy with this practice because you don’t have a choice but to be in a heightened sense of stress and to practice calming your body down,” says kricfalusi. “any other time you’re stressed your body is almost like, ‘i know how to do this. i’ve been here before. i can breathe through this.’”

emma jones is a multimedia editor with healthing. you can reach her at emjones@postmedia.com or on twitter @jonesyjourn.

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