New study dips into the world of cold-water swimmers

A short film captures the journey of students and cold-water swimmers collaborating on a research project testing the saliva of swimmers to uncover any biological changes in the body caused by cold water therapy

Researchers Bridie Hodgson and Katrin Jaedicke from the University of Sunderland have created an experiment to find out if there were any significant changes in the body brought on by cold water swimming.

Working with swimming group the Wild Sea Women and regular sea swimming volunteers, the research team took saliva samples from the participants before and after they entered the water.

This is the first time a saliva sample experiment has been carried out on cold-water swimmers.

Dan Prince’s short film

In June 2020, Wild Sea Women began in Sunderland with just a handful of women keen to connect and dip in the sea together for their health and wellbeing. Since then, the group has taken off and now has 12,000 members across the north-east and into Scotland.

One of those members – Bridie Hodgson, a final-year Biomedical Science degree student at the University of Sunderland – to draw on her scientific knowledge to discover more about any biological changes to these cold-water swimmers’ bodies, which could shed light on the mental and physical health benefits they experience.

Working alongside Dr Katrin Jaedicke, a Senior Lecturer in Applied Biosciences and a salivary biomarkers scientist, together with other final-year project students they spent time with the Wild Sea Women on two mornings at Seaburn beach, taking saliva tests before they entered the water and afterwards. Tests were then carried out in the University’s labs.

Captured on film

The project also attracted interest from north-east filmmaker Dan Prince, who documented the stages, and results, capturing the first time anyone has ever tested cold water exposure in saliva samples, charting the journey between scientists and swimmers.

Dr Jaedicke said: “The enthusiasm from all involved in this project has been the real success story behind the project. These women were so willing to stand there and spit in a tube at 6am on the beach every morning, and be filmed in the process, we were incredibly lucky to have a group so involved in the process.” 

No significant changes

She added: “We wanted to discover if there were any biological changes in the body reacting to the cold-water environment, through saliva tests. While the saliva results did not show any significant changes in the women’s bio-markers, this was more about feasibility than anything else, can we actually do this type of research on a larger scale, and we’ve just opened the doors. Clearly there are changes taking place in the physical and mental wellbeing of these women, and this needs further investigation.” 

Bridie will now take the project forward as part of a master’s degree, with a larger group of the Wild Sea Women, from across the region and Scotland. 

Further study

The new study will look at women going through menopause, checking for biomarkers which play an important role in illuminating relationships among environmental exposures, human biology, and disease. Scientists can use biomarkers to better understand fundamental biological processes. 

There will also be work with the University of Sunderland’s Psychology Department, to measure psychological parameters in collaboration with the swimmers. 

Bridie said: “This is a terrific opportunity to undertake some very fascinating work, and the University of Sunderland has allowed me to put the skills I’ve learned over the previous three years into practice. I have confidence since I have been engaged in every aspect of the project, from recruiting to meeting participants and working with samples. Our next step is to pursue a master’s degree in September with a similar project. The Wild Sea Women made this possible, and Katrin has been an inspiring lecturer throughout my entire journey, providing endless guidance and support.”

Anecdotal evidence

Hayley Dorian, who set up Wild Sea Women in 2020, added: “It’s been a privilege to work alongside the science team at the University of Sunderland, to help with their incredibly interesting research. Although it would have been great for us all to see some tangible proof of the benefits of going into the sea from this particular project, we know from our own personal experience that the sea improves our health in ways we may never understand.” 

Dan Prince explained the process behind creating the film, he said: “Even though the results were not what the students were looking for, I felt their journey was just as important as the research for the story. 

“I really enjoyed working with them on this. Going from the sea to the lab showed two very different worlds, but all starting from only one subject – sea swimming. This was really interesting for me to capture.”

Images: David Woods

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