Taking the plunge: how cold water swimming won me over

Figures of four women swimmers striding into a calm - but cold - sea.
Braving the cold waves: no matter what time of year, a dip in the sea can be fun… and do you good. Picture: author’s own

It is just before seven in the morning and I’m driving down to the Brighton and Hove seafront, wrapped up as warmly as possible, car heater on full. It’s April 16, yet the car thermometer reads just 2°C.  I am on my way to meet my sister Lucy for a swim – in the sea.

It’s exciting to think about what lies ahead: the intense, breath-sapping cold, followed by the warm coffee that I can smell from the flask beside me.  As I turn the corner, I glimpse a handkerchief of sea at the end of the street, the sky a matching bright blue. My sister and I are novice cold water swimmers, so we had carefully assessed the sea conditions ahead of this morning’s session – checking the tide and the height of the waves, to ensure that the sea was safe for us to enter.

Taking the plunge

I started cold water sea dipping last October, in the middle of the Covid pandemic, and I was quickly hooked. Maybe it was something to do with the tedium of lockdown that made me start, and the continuation of home working that motivated me to carry on. Cold water swimming is so life affirming, and offers excitement that breaks up the monotony of the the day-to-day, when you’re working from home surrounded by the same four walls, week after week. 

The sea is about 7°C in Brighton and Hove in April 2021, which might sound crazy, but it’s so exhilarating! (March is the coldest month for swimming; September is the warmest at about 17 degrees, due to the fact that the sea heats up during the summer and then cools down slowly.) 

Swimsuits, socks and woolly hats

When I reach the seafront and meet up with my sister, we notice lots of little groups of people, many wearing the “uniform” of a fleece-lined, long, baggy coat under which you can change and stay warm. Some of us are excitedly disrobing and getting ready to go in, others have just got out of the water; some are only wearing swimming costumes, bravely exposing their pink skin to the weak spring sunshine, while others wear full-body wetsuits. Nearly everyone sports a woolly hat.

Author Louise Serpell and her sister Lucy smiling after their dip in the sea
Author Louise Serpell (left) with her sister Lucy (both of whom are scientists and professors)

Lucy and I pull on our neoprene socks and gloves and walk straight into the sea, shoulders under, screaming as the cold hits. Sharp intakes of breath. Breathing slows as your body almost relaxes into the cold, freezing pain at the collar bone. The sea is flat and calm.

Safety first

We circle around, chatting, our covered heads out of the water, taking a few breaststrokes now and then. We look back towards Brighton’s beach, along to the piers and out to the wind turbines near the horizon. We look up at the sky in awe. But we don’t stay in long… it’s too cold today, and hypothermia is a real risk. Even during a summer heat wave, open water swimming can be dangerous, as the recent tragic fatalities in the UK have shown. The Royal Life Saving Society (RLSS) offers detailed safety guidelines for would-be open water swimmers on its website.

A swimmer emerges from the sea at Brighton in winter - the beach is covered with snow
A hardy winter swimmer emerging from the sea to a snow-covered Brighton beach – Photo by Crispin Jones on Unsplash

We stumble back up the stony beach, which feels strangely warm after the chill of the sea. The air feels warm, too, but we know to get dressed quickly before chill sets in. We pull on layers of dry clothes, thick fluffy socks, fleecy coats. We sit and look out at the sea, sipping hot milky coffee. Watching the seagulls. Life is good. The warm, fizzy feeling lasts for the rest of the day.

Mental health benefits

So what is driving this cold sea swimming obsession? Why are there ever-expanding numbers, particularly of women of a certain age, at the beach, braving the waves year round?

It could be that many of us just find it a lot of fun, and the fact that it costs no money is a plus. But wild swimming is also said to have a number of psychological benefits. Enthusiasts suggest that it reduces stress, helps with depression and encourages a sense of oneness with nature, though there have not yet been any proper scientific research trials to test the claims. 

However, the evidence for exercise as a treatment for mild to moderate depression is well established, and is recommended in the NICE (the National Institute for Health and Care Excellence) guidelines.

A natural high

It is likely that the post cold swim ‘high’ involves the body’s release of natural chemicals like endorphins, dopamine and serotonin. Endorphins relieve stress and pain; serotonin helps you feel happier, calmer and more focused; and dopamine makes you feel motivated, accomplished and productive.  

It is also possible that putting your head under while cold water swimming stimulates the vagus nerve, which transmits information to or from the surface of the brain to tissues and organs elsewhere in the body.

Cold water shock

Recent research by Professor Giovanna Mallucci, of the UK Dementia Research Institute at the University of Cambridge, has shown that a protein (RBM3) produced by cold-shock may be important in the future treatment of dementia.

But it’s important to proceed with caution, because there are also significant risks associated with immersion in very cold water, especially for those who are not acclimatised. It is therefore always essential to heed safety advice. 

Walkers at Seven Sisters near Eastbourne, where the green grass of the South Downs meets the blue of the sea and the white of the chalk cliffs
Photo of walkers at the Seven Sisters near Eastbourne by Marc Najera on Unsplash

The ‘blue green exercise’ route

Even if you decide that cold water swimming is not for you, it may be worth taking some exercise on the sea shore. Because we do know that ‘blue green exercise‘, that is, working out in green spaces near (or in) water, is more beneficial to mental health than exercising in a gym, at home, or even on urban pavements. So, if plunging into cold water is not your thing, maybe instead try a jog round Hove Lawns, or a brisk walk at Seven Sisters, for an increased sense of wellbeing.

For me and my sister, it’s the sense of achievement and community spirit involved in swimming in the cold Brighton sea that makes it worthwhile, regardless of the other possible health benefits. Perhaps it is, in fact, our after-swim chats over thermoses of coffee while sitting on the beach that have the most positive effect of all!

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