Can swimming in cold water protect brain against dementia? New study suggests it may be possible
Swimming in cold water may be able to protect the brain from neurodegenerative diseases such as dementia, according to researchers from University of Cambridge. They monitored people who swam in the cold waters of Parliament Hill Lido in London during winter and found that they had elevated levels of a “cold-shock” protein (RBM3) that may protect against neurodegenerative conditions. A 2015 study on mice had shown that the protein offers protection against the onset of dementia.
The current work has been discussed by Professor Giovanna Mallucci, center director of the UK Dementia Research Institute at the University of Cambridge, in an online lecture, but it has not yet been published in a scientific journal. While the research is still at an early stage, Professor Mallucci hopes that the findings could help in dementia treatment in the future. Only swimmers who got cold had raised levels of the protein RBM3, hence the aim is to find a drug that has the same effect. “If you slowed the progress of dementia by even a couple of years on a whole population, that would have an enormous impact economically and health-wise,” Professor Mallucci told BBC News.
Dementia is the loss of cognitive functioning — thinking, remembering, and reasoning — and behavioral abilities to such an extent that it interferes with a person’s ability to perform daily activities. According to the World Health Organization (WHO), globally, around 50M people have dementia, and there are nearly 10M new cases every year. Alzheimer’s disease is the most common form of dementia and may contribute to 60 to 70% of cases. Of those at least 65 years of age, there were an estimated 5M adults in the US with dementia in 2014 and the number is projected to be nearly 14M by 2060.
Treatment of dementia depends on the underlying cause. Neurodegenerative dementias, like Alzheimer’s disease, have no cure, though there are medications that can help protect the brain or manage symptoms such as anxiety or behavior changes. Research to develop more treatment options is ongoing.
The destruction of synapses in the brain, which are the connections between cells in the brain, causes dementia. Hibernating animals lose up to 30% of their synapses before their annual winter sleep, but the connections are reformed when they wake up in the spring. A mice study, previously published in the journal Nature, revealed that this effect is mediated by a “cold shock” protein in the brain called RBM3.
In the current study, the Cambridge team found that many swimmers in their research had elevated levels of RBM3 in their blood. All of these swimmers became hypothermic during their dips. Professor Mallucci believes the findings suggest that humans can also produce a “cold-shock” protein, like hibernating mammals, which could help create new brain connections. The team compared the cold-water swimmers with people doing Tai Chi. “We compared you to a bunch of people doing Tai Chi who didn’t get cold and none of them got increased levels of this protein but many of you did. It tells us that cold does induce this protein in humans; you’re the first non-patient cohort to show that cold water swimming raises this protective protein,” she told the swimmers, reports The Independent.
However, Professor Mallucci has cautioned against cold water immersion as a possible treatment for dementia, explaining that the risks outweigh any potential benefits as the shock of freezing water can cause heart attacks and strokes, as well as a rise in blood pressure and heart rate.
According to Professor Mallucci, the next steps are to conclusively prove that the protein slows down dementia and to find a drug that stimulates the production of RBM3. “The challenge now is to find a drug that stimulates the production of the protein in humans and, more important still, to prove it really does help delay dementia," she told BBC’s Radio 4 Today program.