For the many enthusiasts for sea and lake swims, the longing to immerse yourself in cold water, to feel the dopamine rush as your body temperature changes - this can bring not only an immediate thrill but a sense of great, lasting wellbeing.
Those who submerge themselves regularly speak of the feeling of euphoria. Why, though, and how? And what will the British Government's Environment Agency do to help others realise the physical benefits and mental health benefits of this rapidly growing pastime.
Wild swimming or open water swimming - is it good for you? 
Open-water swimming is becoming increasingly popular as people recognise and act upon the urge to spend time in blue spaces. Oceans, rivers and lakes have a primal appeal for many people and a growing number are taking the plunge to discover the benefits of open-water swimming for themselves. 
The Â̲èÖ±²¥'s Dr Catherine Kelly is a leading voice in the new understanding of how wild swimming and visiting bodies of water can bring a special sense of wellbeing.  The author of  Blue Spaces: How and why water can make you feel better  (2021), Catherine Kelly is an advisor for the Environmental Agency and spoke in January 2023 at the  All Party Parliamentary Group on outdoor and wild swimming, chaired by Lord Bethell, health and wellbeing spokesman.
She presented research synthesis and policy/practice challenges and opportunities for using outdoor swimming and blue spaces for social prescribing and wider societal benefits. With an invitation to sit on a potential new parliamentary advisory committee, we could well find in the near future that social prescription includes recommendations of a regular swim outdoors with an approved provider, for those who need specific support, or who experience barriers to access.
But what is it that takes people to the open water for exposure to cold three times a week and what are the benefits of cold water swimming? Why does the simple presence of an expanse of water have such a positive effect?
What are blue spaces? What are the benefits of blue spaces?
Blue space(s) is a key phrase for policy-makers, with a gradual recognition that they should be considered alongside green spaces for their therapeutic value. Exactly what are blue spaces and why are they important? The notes that blue spaces are officially described as ‘outdoor environments – either natural or manmade – that prominently feature water and are accessible to people.  Basically, the collective term for rivers, lakes or the sea. Catherine Kelly goes further in For her, it "refers to all natural waters – oceans, seas, rivers, ponds, streams and waterfalls. If we want to be looser with the term, we can include fountains, canals, outdoor swimming pools and even your own bath or shower at home."
 While the benefits of nature and green space are well understood, it is only now, through the work of Catherine Kelly and others that we are beginning to discover the depths of the issues around blue space. And this has led to commissioned research and invitations to Catherine Kelly and her colleagues in this academic area.
There is, Catherine Kelly explains, something we understand intuitively around blue space, a feeling of subjective wellbeing. The growing interests of government and research funders is now helping this to be scientifically understood. This will gain an evidence-base for the benefits of wild swimming and cold-water swimming, but will also bring knowledge to recognise the wellbeing of those who never swim but recognise the sensation of the water in its presence.
What is it about water that helps us? In essence, we know intuitively that for many of us we simply feel better when we are in or near water – ‘subjective wellbeing’, where it is self-reported, or felt. A new research agenda is however emerging and slowly beginning to receive funding, where a more scientific, or objective, evidence-base is being investigated to prove the benefits of blue spaces across a range of human wellbeing areas.
Wild swimming or cold water swimming could have major health benefits
"Moving our bodies increases our cardiovascular fitness, releases mood-enhancing endorphins and helps with muscle building and bone density improvement," says Catherine Kelly in  . Water swimmers report on the sensations of swimming in cold water, of submerging yourself in deep water and swimming in icy temperatures. Well-referenced research evidence suggests that swimming in cold temperature water can support immune health.  A   found that  cold water swimmers gain  significant increases in white blood cell counts. The body produces more white blood cells when faced with a stressor, and  open-water swimmers find it  stimulates their release as the heart rate increases. Exercise helps and there are also sensations gained as you come out of the water. But it's not all about submersion. Our therapeutic relationship with water goes far beyond cold-water therapy, wetsuits and a form of exercise. 
Swimming in open water can boost dopamine and serotonin levels
As well as the  Physical Wellbeing, Catherine Kelly also points to the  Psychological Wellbeing, or mental benefits of water, and the  Social Wellbeing,  where a body of water might bring opportunities for exploration and adventure or togetherness as like-minded cold water swimmers become friends. 
Mental health and stress levels. can all improve by being in or next to water, as research shows. It can reduce our blood pressure, slow our breathing down and allows our parasympathetic nervous system to function properly. Research evidences a better night's sleep since subjects started swimming.  Vital for effective brain function and a strong immune system, reported benefits include an increased metabolism and an improvement in mood. Being in and near water reduces the stress hormones cortisol and adrenaline that course through our bodies and make us feel unwell. Interesting research is emerging too on the anti-inflammatory powers of cold water.
 Inflammation for example plays a role in many diseases and in depression and anxiety, and immersing ourselves in cold water regularly, stimulates the vagus nerve to give us powerful mood enhancing effects.  In addition, looking at water, the horizon, the sky and any surrounding habitats gives us a sense of awe, calm and perspective. In water, we come home to ourselves – our bodies and minds, in a way that few other places offer so simply and effortlessly. Catherine Kelly also notes the social wellbeing aspects, through which camaraderie, an acceptance of each other and of the water, keeps people excited to return.  In essence, blue space allows us to connect to ourselves, to the water itself, and to each other.
What are the benefits of open water swimming? Ask Catherine Kelly, author of Blue Spaces
Oceans, seas, rivers, ponds, streams and waterfalls - even fountains, canals, outdoor swimming pools -- they are all blue spaces.  Most people agree that water makes us feel better. Research shows that a walk by the water is the preferred environment of many humans.    asks why so many of us feel drawn to water. As well as the innate soothing quality that water brings there are huge questions on the importance of water environments and their therapeutic benefits in our lives. Blue Spaces  examines the significance of water across cultures, the most up-to-date research and the evidence that supports the importance of blue space and  provides practical ways that we can all integrate wellbeing exercises into our lives whether we live by the water or not.
Dr Catherine Kelly is a geographer with research interests across sustainability, tourism and wellbeing. She is interested in the importance of water-based 'therapeutic landscapes' for physical, psychological and social wellbeing and also looks at how wellbeing can be used to advocate for personal relationships with the coast and its stewardship/environmental conservation. 
Find out more about the work of our researchers in the Centre for Aquatic Environments and the Centre for Spatial, Environmental and Cultural Politics
Referenced: Lombardi G, Ricci C, Banfi G. Effect of winter swimming on haematological parameters. Biochem Med (Zagreb). 2011;21(1):71-8. doi: 10.11613/bm.2011.014. PMID: 22141210.