Diving deeper into the benefits of cold water swimming

Man jumping into cold water

It has already been credited with improving psychological wellbeing, now scientists are suggesting it may offer protection from the mental deterioration of dementia.  Is it a wonder drug?  A new psychoanalytical therapy? Nope, just a simple dip in the pool - albeit a very cold one.  

As we have already explored in the (med)24 journal, cold-water swimming is attracting a growing body of devotees.  The number of people who enjoy ‘chilly-dipping’ whether in lidos, rivers, ponds or the sea is growing rapidly in the UK, partly due to the growing attention the pastime is receiving, partly due to the increased difficulty during the pandemic of accessing indoor pools and gyms.  

Ask anyone who regularly takes the plunge about the health benefits and the answer is overwhelmingly positive.  It keeps you fit, lifts the mood and helps ward off coughs and colds.  This anecdotal evidence is supported - albeit to a limited extent - by a 2018 study which showed how cold water swimming could have a highly positive impact on mental health and people suffering from major depressive disorders.

Now the scientists have gone further still.  A report from Cambridge University has linked cold-water swimming with the prevention of degenerative brain diseases such as dementia.  The study, presented in an online video, found immersion in cold water was linked to the production of a protein in the brain, called RBM3. This protein, now called the ‘coldshock protein’ is not new to science. It is known that RBM3 prevents synapses, and therefore the brain, from degenerating.  However, the protein is found far more prevalently in mammals whose body temperature falls dramatically in winter during hibernation, than in humans who spend the cold months in centrally heated houses. It is thought the protein is key in helping the brains of hibernating mammals to repair themselves after their long winter sleep.

The Cambridge study wanted to explore this phenomenon further. So, they took a group of swimmers who regularly used the lido at London’s Parliament Hill and compared them with another group of people who exercised at the same spot doing Tai Chi but not getting into the pool.  The study found that the swimmers had discernibly higher levels of RMB3 in their bloodstream than those doing the Tai Chi.  

The findings do not mean that anyone concerned about dementia must immediately jump in the nearest stretch of cold water.  The researchers, led by Prof Giovanna Mallucci, of the UK Dementia Research Institute's Centre at the University of Cambridge, hope their findings will lead to the discovery of new drug treatments that may have the same effects as cold water swimming.  This will no doubt come as something of a relief to those who prefer to spend cold days lapping up hot chocolate instead of lapping a cold pool.  

For some a drug may also be safer way of increasing RMB3 levels. Swimmers who had elevated levels of the cold-shock protein had got decidedly chilly during their dips, their core body temperatures dropping to hypothermic levels of around 34°C following immersion.  It perhaps goes without saying that this can be dangerous, particularly for those new to the activity.

But if the research is right about RMB3, its effects could be profound.  The number of people suffering from dementia in the UK is thought to be 850,000 and rising.  According to the Alzheimer’s Society something like 1 in every 14 people over the age of 65 is affected by the condition.  There is clearly a huge demand for a treatment that works.

As ever with medical research, progress is likely to be slow and uncertain. What is more certain though is the satisfaction that the nation’s outdoor swimmers will take from the news of the potential health benefits.  They would no doubt say they already knew.