I too swam regularly in the sea all year round when I was a volunteer life guard sixty years ago and can attest to the health - giving effects.
I note with interest, however, that contributors to this thread would appear to have a high average age. I do hope some younger members will post their experiences of cold water swimming so we oldies don't get the impression that we were much tougher than today's youth.
I live within ten minutes walk of the beach to if if I go there every day at the same time I will find the same people swimming for better mental health reasons, even in winter as it's the cold they say that's the curative.My neighbour who’s retired wild swims 2 to 3 times a week all year round, riddled with health issues & swears blind it’s what keeps him going.
Apparently there’s a lot of folk doing it now as it’s good for the mind & body, said the older generation prefer to wear trunks or bathing costume & the younger generation wet suits.
Its also a something that’s been done since pre Cristian times as rivers/ lakes were cleansing & pure.
We even had god’s; goddesses & deities in our waters..