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Is cold water swimming the key to dementia treatment?

Is cold water swimming the key to dementia treatment?


By Rose Elizabeth Dodd

Taking the plunge into glacial water, whilst being a touch unbearable, comes with a multitude of benefits. Be it swimming in an outdoor pool, or – a little more wild – a river, lake or the sea, a drop in one’s core body temperature triggers a natural high, frequently described as ‘euphoric’. This high has protective powers over the body. 

Outdoor swimming is a sport that not many people choose to undertake but, those who do – swear by it. Speak with any cold water swimmer and they’ll likely tell you all about the joys of submerging yourself into cold and wild waters.

An invigorating and bitter cold swim not only burns calories but also improves blood circulation, reduces inflammation, aids in pain relief and has been known to help ease the symptoms of migraines and arthritis.



Numerous accounts suggest that the breath-taking cold also reduces stress, improves mental health and helps normalise sleeping habits. Cold-water swimming allows you to hit the reset button, leaving the weights of today in the depths of the water; clambering out with a clear head.

A dip in the big chill comes with a range of social reimbursements too. There are so many swimming groups and clubs, making it a great way to make new friends.

Cooling of the body to a hypothermic state (sub-35°C) possesses protective properties for the brain and body. How exactly the cold exerts its protective effects is yet to be fully understood.

It has recently come to light that the cold and thus, cold water might protect the brain from dementias such as Alzheimer’s disease.

Dementia is a prevalent, life altering and debilitating group of diseases whereby the sufferer’s memory, thinking, behaviour and ability to perform everyday activities deteriorates. Dementia impacts the life of the sufferer and the sufferer’s family and friends. Approximately 50 million people worldwide suffer from dementia, most commonly Alzheimer’s disease, and the prevalence is rapidly increasing. Currently, there is no cure for dementia, just a small range of medications that slow its progression. 

Animal models of Alzheimer’s disease have been found to express a reduced quantity of a protein called RNA-binding motif protein 3 (RBM3). RBM3 is involved in rebuilding lost and damaged neural connections (synapses) in the brain.

 Elevated RBM3 is associated with hibernation in animals. During hibernation animals lose synapses in order to conserve energy. They redevelop these synapses upon awakening when RBM3 levels are increased.

Alzheimer’s disease is defined by a distinctive loss in brain cells resulting in deteriorative symptoms like memory loss. Studies have shown that higher levels of RBM3 are protective in mice with early stage rodent forms of Alzheimer’s disease, helping reduce the loss of nerve connections and subsequent cell death. These mice lived longer than those with lower levels of the protein. When levels of the protein were lowered, the disease progressed more quickly. When levels of the protein were lowered in healthy mice, the mice exhibited less synaptic regrowth and displayed memory impairments as a result.

Interestingly, RBM3 is synthesised in higher quantities at colder hypothermic temperatures.

Up until recently, all knowledge associated with RBM3 and hypothermia was attained in animal studies due to the ethical implications associated with making humans hypothermic.

A study at Cambridge University, conducted by Professor Giovanna Mallucci, had the breakthrough idea to investigate the levels of RBM3 protein in people who voluntarily make themselves hypothermic, cold-water swimmers!

A group of avid winter, cold-water swimmers from Parliament Hill Lido in Hampstead Heath volunteered to take part in the study. The Cambridge team found that a significant number of swimmers had markedly elevated levels of RBM3.

To ensure this was not fluke, they repeated the measurements every winter for three years. They also compared the recorded levels of RBM3 from the swimmers with that of a group of people who practiced Tai Chi on the poolside at the Parliament Hill Lido. RBM3 was not elevated in the Tai Chi group.

Scientists hope that this might be the key to understanding how we can restart the process of synapse renewal in humans with neurodegenerative dementias. RBM3, its elevation in recreationally hypothermic humans, and its restorative activity in animals hold an exciting new avenue for potential dementia treatments. The next step is to find a drug that stimulates the production of RBM3 in humans and to prove that it helps.

Of course, the evidence is not yet conclusive; so don’t take the plunge thinking that it’s a guaranteed preventative measure for dementia.

If you plan to start cold-water swimming, be sure to do it safely. Below is a list of safety measures that should be considered prior to starting.

  • Be aware of the risks, especially in open waters.
  • Know your limits.
  • After swimming, warm up slowly – get dried off, dressed, and wrap up. Have a warm drink and a sugary snack. Warming up too fast can cause chilblains.
  • Familiarise yourself with the symptoms of hypothermia; these are confusion, shivering, pale skin, blue lips, fatigue, and hyperventilation. Seek medical help if necessary.
  • Immerse yourself slowly so to avoid the gasp response as this can cause you to breathe in, putting you at risk of drowning.
  • Never swim under the influence.

A lovely book on the benefits of swimming is The Lido by Libby Page.