The MRI image — taken from a volunteer asked to take a five-minute dip in a 20C (68F) bath — shows changes in tiny parts of the brain that connect to each other.
It marks the first time that researchers have ever seen it.
They said this brain activity explains why people feel more upbeat and alert after taking a cold bath or a plunge in a river, lake or the sea.
Brits in their droves are turning to outdoor swimming and opting to have cold showers in a bit to keep fit and boost health.
Researchers from Bournemouth University said the mental health benefits of being in cold water are ‘widely known’ from previous studies that quizzed participants before and after they took a dip.
But the scientists wanted to examine how the shock of going into cold water actually affects the brain and drives better mental health.
They recruited 33 healthy volunteers, aged 20 to 45, who were immersed in a pool of water — heated to 20C (68F) — for five minutes.
Swimming fanatics say this temperature is comparable to that of lakes and rivers during the summer.
Each volunteer was quizzed on their emotional state and had an fMRI scan — which detects brain activity as well as its structure — before the bath and immediately after, so the researchers could spot any changes in their mood and brain activity.
The results, published in the journal Biology, show increased connectivity between the medial prefrontal cortex and the parietal cortex — indicated by red patches on the scans.
These parts of the brain are involved in maintaining attention, helping decision-making and controlling emotions. Survey responses showed that participants felt more active, alert, attentive and less distressed after the exercise. Dr. Ala Yankouskaya, study author and senior lecturer in psychology at the university, said, ‘All tiny parts of brain are connected to each other in a certain pattern when we carry out activities in our day-to-day lives, so the brain works as a whole.
‘After our participants went in the cold water, we saw the physiological effects – such as shivering and heavy breathing. ‘The MRI scans then showed us how the brain rewires its connectivity to help the person cope with the shock.’
She said, “So when the participants told us that they felt more alert, excited and generally better after their cold bath, we expected to see changes to the connectivity between those parts.”
“And that is exactly what we found.”
The team plans to use their findings to understand more about the wiring and interactions between parts of the brain for people with mental health conditions.
Dr. Yankouskaya said, “The medial prefrontal cortex and parietal cortex have different wiring when people have conditions such as depression and anxiety.”
“Learning how cold water can rewire these parts of the brain could help us understand why the connectivity is so different for people with these conditions, and hopefully, in the long-term, lead to alternative treatments.”
-Daily Mail.uk