After the First World War and into the 1920’s a new passion for fresh air and sunlight overtook people. Bathing costumes were gradually reduced in size and the fair skin complexion was traded in for the sun tan, all this giving way to an end of ‘Puritan’ thinking.
Gerald Heard in his book the 'These Hurrying Years', published in 1934. Has this to say about the changes in ideas of hygiene:-
'Just below the level of full consciousness were the ... changes in ideas of hygiene. Fresh air had won and pushed its victory against the curtain, blind, wrap and flounce so far that it began to pass the Plimsoll Line of prudery. A new issue was then joined, and the Hygienists, who till then had been allies of the Puritan, began to swing over towards the libertine. "To the pure all things are pure" was extended to the rather different and not so clear assumption that "to the naked all things are unexciting".
It may be true, but up to the present passion prevents sufficient scientific experiment. What is clear is that the fresh-air campaign had ceased to be physiological and had become psychological. That change involved a discussion of issues much wider than costume, though to the psychologist costume had always been a clue to understanding the subconscious sex life. Quite sane and kindly people went on to ask not whether clothes helped chastity but whether chastity itself was helpful.'