Ben Franklin was a weird dude. As we've covered before, he was extremely difficult to work with. John Adams was once forced to share a bed with him, and was exposed to Franklin's weirdest hobby: taking regular "air baths."
Franklin believed - somewhat correctly, though against conventional wisdom of the day - that illness spreads via stagnant air. He thought it was "frowzy corrupt air" (grundle funk) trapped by oppressive clothing that was the source of most ill health - and he had just the solution!
In this letter to his doctor buddy, he raves about his radical new discovery of... reading naked and then taking a nap: