RESEARCH linking cold water swimming to dementia should not be interpreted as a public health message that regular dips in a freezing loch will protect you against the disease, the professor leading the study has cautioned.

Scientists detected markedly elevated levels of a “cold-shock” protein in the blood of regular winter swimmers at London’s Parliament Hill Lido which they found could slow the onset of dementia and even repair some of the damage in trials involving mice.

The prorein, RBM3, had also been found in hibernating mammals, whose brain connections are lost over winter but repair when they awake in Spring. However, it had not been detected in human blood until this point.

All of the swimmers become hypothermic, with core temperatures as low as 34C.

READ MORE: Screening for Alzheimer's could be a reality within five years as study warns of 12 'risk factors' for dementia

Professor Giovanna Mallucci, who runs the UK Dementia Research Institute’s Centre at the University of Cambridge, which carried out the study, urged caution with the findings.

She said: “What you are not going to get is that anyone who swims in cold water is protected from dementia. 

“I’m a scientist, I’m absolutely not here to advocate on behaviour. I caution against getting cold – that has an immediate acute risk to people.”

However she added: “These are things that are going to be a contribution towards having factors around that help you repair your brain cells.”

READ MORE: The Scots area classed as one of the best in the world in dealing with dementia 

Another study in Berlin found that cooling cardiac patients during heart surgery also produced the same protein, but according to Prof Mallucci the effect is likely to be temporary.


She said there would be “no easy link” tying the findings to countries such as Finland, where the benefits of a hot sauna then a cold plunge are touted, or to people who live in colder climates. 

She said: “There are all sorts of confounding factors that affect mortality.

“We are what is called homoeotherm so we as human beings so we keep our body temperature at 37, whether we live in the Arctic circle or the Sahara. People who live in the Arctic circle don’t have a lower body temperature, neither do they get cold if they can help it. 

“We are the nutters that go cold water swimming, you wouldn’t catch an Eskimo doing that.”

The crucial part of the research, she said, is the discovery of a protein which can help the brain repair itself.

She said: “What’s very exciting is that it harnesses the brain’s own capacity to repair itself. 

READ MORE: Think Dementia factsheet: Young onset dementia 

“It’s taking something that happens normally and amplifying it.  Will we get a drug out of it? I don’t know but it’s certainly very impactful in the experimental model and that’s all we can say.

“Because cooling is dangerous and you can’t do it for long, the idea is we have discovered the pathway that leads to this protein, then the next step is to find a drug or a way of increasing it that will protect the brain.

For those who advocate open water swimming the latest study has reinforced what they believe is a health-improving pastime.

Colin Campbell of Scottish Swimmer Open Water Swim Coaching is about to launch a social enterprise which aims to improve access to the sport.

He said: “I hugely welcome another piece of evidence-based research that confirms what most open water swimmers already know: that regular swims in cold water are great for your mental and physical health.

“I would, however, advise those new to the sport to approach it cautiously and to learn from experienced swimmers or a coach,

“I hope we will continue to see more scientific research that demonstrates the sport’s incredible health benefits."

“I’m sure they would have a willing army of volunteers.”

Dr Sophie Bradley, who is part of the Scottish Dementia Research Consortium, welcomed the findings.

She said: "This exciting study follows on from a previous discovery from the Mallucci laboratory whereby the scientists discovered that a so-called “cold shock” protein, RBM3, is responsible for stimulating the reformation of connections between brain cells following cooling.

"However, this is a very early study, and it remains to be tested whether drugs can be developed to stimulate the production of this protein and protect against disease progression."


The Herald's Think Dementia campaign aims to improve care standards for dementia patients in Scotland.