I went wild swimming in a chilly river and haven’t had a panic attack since

I was at my wits’ end when I finally lowered myself into the River Wensum, in Norfolk, at the tail end of autumn. My quest to find a cure for my severe anxiety and decades’ worth of weekly – sometimes daily – panic attacks was going badly. I’d exhausted conventional treatments, so I decided to try something different. An anaesthetist, Mark Harper, had told me about research he had co-authored into cold outdoor swimming as a…