By Amy Liptrot

A few years ago, after I got out of rehab for treatment of alcohol addiction, I returned from London to the Orkney islands, where I grew up.

I was newly sober, unemployed and fragile. Back home, I joined an eccentric group of mostly women, the Orkney Polar Bear Club, who, each Saturday morning year-round, swim in the sea at different spots on the island coastline. We decide our location the night before, using analysis of the wind direction and height of tide. We swim at beaches, in rockpools, down rusty ladders from piers and out around shipwrecks.

The water is always bracingly cold - from 13c at the height of summer, to an icy 3c - and I wear just a swimsuit (albeit with neoprene boots and gloves, and usually a woolly hat). I don't stay in for long, but it's enough.

With seaweed and the Atlantic on my skin, up close to anemones and limpets, I am alive. I always feel more awake when I get out, my skin and my brain tingling, with the fresh perspective you get from being at duck level.

I also swam alone during the two winters I spent on the tiny island of Papay, the most north-westerly of the Orkneys. Sometimes I swam naked and felt like the selkies of Scottish folklore: magical beings who live as seals in the sea, then shed their skins to become human on land.

In a way I was performing my version of the cold water baths historically used in the treatment of alcoholics. I was adjusting to a sober life and finding new ways to enjoy myself.

Now, the wild swims function for me in several of the same ways as alcohol used to.

First, they provide a buzz: the 'cold water high'. Second, they're an effective method of stress relief. The cold ocean blasts away anxiety.

My focus is simply on not drowning, and when I clamber back on to the beach, I feel almost reborn and my worries are smaller.

I also use the swims to celebrate the changing seasons. On the spring solstice, I will have been sober for five years and I plan to celebrate, with joy and gratitude, in cold water.