- Kelly Shen, Science Column
Cold water swimming might be a way to protect the brain from degenerative diseases such as dementia, researchers from Cambridge University have discovered. For the first time, a “cold-shock” protein has been found in the blood of regular winter swimmers at London’s Parliament Hill Lido. Why is that important? The exact same protein has been shown to slow the onset of dementia and even repair some of the damage it causes in mice.
Each year, there are around 10 million new cases of dementia. It is a neurodegenerative disease that slowly inhibits one’s memory, thinking, behavior and the ability to perform everyday activities. It is also known as Alzheimer’s and most commonly affects the senior population. We still aren’t sure what exactly causes it, (at first it was thought to be beta-amyloid plaques and toxic tau clusters, however that got refuted not too long ago), but researchers are working to find a cure.
Why is cold water promising?
The idea of using cold water comes from hibernation, and an animal’s ability to hibernate when faced with cold temperatures. It’s been known for decades that cooling people down can sometimes protect their body parts. For example, when cardiac and neuro surgeries are performed the patient is often cooled during surgery (but not for too long). What is not understood is why the cold has this protective quality. Part of dementia is essentially the breaking down and creation of synapses, which are connections between the cells of the brain. In neurodegenerative diseases, these connections are lost. This is why there are the symptoms of memory loss, confusion, and behavior. Here’s the really interesting part: brain connections are also lost when animals like bears and hedgehogs go into hibernation. 20-30% of their synapses stop working to conserve energy. When they wake up in the spring however, these connections magically reappear.
The Cambridge dementia team decided to test this out: They cooled ordinary mice, and mice with Alzheimer’s disease and prion (neuro-degenerative) disease, to the point where they became hypothermic, which means their body temperature was below 35C. On re-warming, they found only the ordinary mice could regenerate their synapses; the Alzheimer’s and prion mice could not. The “cold-shock” protein called RBM3 soared in the ordinary mice, but not in the others. It suggested RBM3 could be the key to the formation of new connections.
Next, they decided to test this out on humans. During the winter, the Cambridge team tested a number of winter swimmers and used a nearby Tai Chi group as a control. The results showed that the swimmers had elevated levels of RBM3, while the Tai Chi group, who also went into the water, didn’t show an increase in RBM3.
Can cold water actually work?
What these experiments show is that humans are capable of producing this “cold-shock” protein, just like hibernating mammals. The problem is that immersing people in cold water has many risks, so it might not actually work. The mission now would be to find a drug that stimulates production of this protein, and prove that it does help to delay dementia.
“Complete rebound of a drop of water just after impact with a body of water.” by José Manuel Suárez. Licensed by CC