Cold water swimming may protect the brain from degenerative diseases like dementia, researchers from Cambridge University have discovered.

In a world first, a “cold-shock” protein has been found in the blood of regular winter swimmers at London’s Parliament Hill Lido. The protein has been shown to slow the onset of dementia and even repair some of the damage it causes in mice.

The link with dementia lies in the destruction and creation of synapses – the connections between cells in the brain. In the early stages of Alzheimer’s and other neuro-degenerative diseases, these brain connections are lost. This leads to the cascade of symptoms associated with dementia – including memory loss, confusion and mood swings – and, in time, the death of whole brain cells.

Could cold slow dementia?

A number of other researchers have found similarly higher levels of RBM3 in babies and heart and stroke patients who have been made hypothermic. What these findings show, says Prof Mallucci, is that – just like hibernating mammals – human beings produce the “cold-shock” protein.

But the risks associated with getting cold outweigh any potential benefits, so cold water immersion is certainly not a potential dementia treatment, she says.

The challenge now, she says, 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. Dementia is predominantly a disease of the old, so even a relatively short delay in the onset of illness could have huge benefits for individuals, and the wider population.