Flash: "getting cold gets you colds..."
Ya know, when I were a lad, there was an absolute rule for kids: they had to be dry and warm in winter or they would get a cold.
So, no swimming if the temperature was below -7, and no outdoor gymnastics either; and if you got snow inside your clothes or were out to long in the cold, then you got a change of dry clothes and a warm drink immediately.
So I made the mistake of mentioning this in the US on occasion. Poo, said they (quite reasonably, this was in California); colds are due to viral infections, not discomfort. "Old wives tales" (they were very ideologically unsound out west back then).
But, said I, rhinovirus infections are endemic and chronic sub-clinical infections common; is it not plausible, as opposed to scientificially demonstrated through hugely expensive controlled double blind studies (ok, single blinds), that getting very cold and wet is stressing and will lead to a temporarily depressed immune system allowing infection to flare?
Whatever, said they. Well, actually they agreed this was plausible, but quite correctly remained skeptical until actually demonstrated through a suitably rigorous study.
And, now the Welsh have done so. Bless them, and the little Grauniad too, good science journalism