Polar Bear Plunge




There are many ways of seeing in the New Year. Most people choose celebratory excess, partying like there’s no tomorrow under a fireworks-filled sky. Others, meanwhile, elect a more subdued approach, surrounded by friends and family. Some people, however, opt for an entirely different end of year ritual.

“Let’s do a polar bear plunge!” enthused my Canadian friend excitedly when we sit down to plan our upcoming New Year celebrations. An expat living in England (like myself), my friend sees no reason why her recent intercontinental move should interrupt her annual end of year cold-water cleanse.

“You’ll love it,” she adds, quickly, seeing the dubious expression on my face.  “It’s invigorating and good for you!”

I don’t doubt for a minute that a dip in The Thames on New Year’s Day will be invigorating. But is it good for me?
This is a virtue of cold-water swimming often championed by devotees of this seemingly crazy pursuit. Advocates of cold-water swimming claim it confers all manner of health benefits, from alleviating muscle and joint pain, to reducing colds, and improving skin tone and skin health. Some even claim it can increase libido and prevent heart disease and cancer.

Yet it also, evidently, presents serious potential health risks, as deaths from immersion hypothermia are prevalent in high latitude countries. Cold-water shock causes your body to go into defence mode, eliciting its fight-or-flight response. Immediately upon immersion in cold water, your blood pressure increases rapidly as the blood vessels supplying your limbs constrict to squeeze blood towards your chest. This makes your heart work harder and faster. “Cold shock” also makes your ribcage contract, leading to uncontrollable hyperventilation and can, potentially, disturbing the heart’s rhythm.

Despite these risks, outdoor cold-water swimming has a dedicated global following. The Chinese take to their frozen rivers in annual frozen water swimming festivals, while in Nordic countries, winter swimming is not so much a sport as a national cultural activity. In the US and Canada, meanwhile, a dip in Arctic waters has become a New Year’s Day tradition with 1000s of people participating in polar bear plunges. Even in the UK, icy swims have become regular Yuletide events for many resilient folk. But if swimming in cold water is such a physiologically stressful activity, how are so many people able not only to vociferously extol its merits, but also regularly brave the plunge into this potential liquid death?

A key part of the answer to this question is that they do so, regularly. The human body has a remarkable ability to acclimatise to very cold water, and experimental studies have shown that the “cold shock” response to an icy plunge diminishes with repeated immersions. In fact, research shows that just three minutes of cold-water immersion on four consecutive days can eliminate the cold shock response altogether. This rapid adaptive response, allows regular cold-water enthusiasts to endure significantly less physiological stress when swimming in frigid waters. This is important because, it turns out that, while excessive physiological stress is destructive, a little bit of stress on our bodies can be a good thing.

Short periods of mild stress can help us perform at a higher level, can improve our mental functioning, and can even prime our immune systems. In other words, a bit of stress can help to keep our body ‘on its toes’. Experimental studies have shown that the mild thermal stress experienced when regularly bathing in frosty water strengthens the immune system by increasing white blood cell counts, the concentrations of other immune system cells, and levels of antioxidants in the blood (hence, the alleged beneficial effects on cancers). Other studies, meanwhile, reveal that cold-water swimming can boost the metabolism and improve blood circulation and skin tone.

The problem is, however, that because physical activity is itself a mild stressor, all of these physiological responses will also arise from other physical activities, including swimming in warm water. To date, studies that have attempted to separate the health effects of swimming per se, from the health effects of the temperature of the water, have provided equivocal and often conflicting results. For example, one widely-cited benefit of icy swimming is increased testosterone production and an improved libido. A quick Google search, however, reveals research that both supports and contradicts this claim. Add to that the fact that people who regularly jump into freezing water tend to be healthier and more ‘vigorous’ then the average person to begin with, and you are left with little evidence to suggest that a cold-water swim is any better for you than a swim in a tropical lagoon.

Nevertheless, there is one positive aspect of swimming in freezing water over which no one will argue: when you get out you feel great. As anyone who has ever swum in cold water will tell you, once you’re out and dry, you feel energized, invigorated, and more “alive” than ever before. That buzz is real. Cold-water causes the body to release large amounts of endorphins, which are the bodies’ natural painkillers. These feel-good hormones flood the brain and provide the sense of elation and wellness reported by most cold-water swimming devotees. But that buzz is not only hormonal it is also psychological. For most people, the psychological challenge of diving into 5oC water far outweighs the physical ordeal involved. For this reason, the sense of achievement that comes from conquering that mental barrier is arguably one of most tangible benefits of cold-water swimming.

My polar bear plunge in The Thames is scheduled for 1pm on the 1st January 2013. I have just five days to psyche myself up to this crazy escapade, and I’m going to need it every minute of it. Yet I know that afterwards, as I stand shivering on the banks (probably in the rain, but hopefully not in snow) with the blood rushing back to my skin, I will be high on endorphins and buzzing from the psychological boost of having overcome such a loathsome task. I will feel ‘alive’, euphoric and utterly invincible.

Sounds like a fine way to see in the New Year. I just have to remember to pack some warming whiskey for afterwards. I think I will have earned it!


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