While the theme of Yom Kippur is a day of Teshuva, a very integral part of the Mitzvas Hayom is the Mitzvah of innuy – i.e. the Mitzvah to afflict oneself on Yom Kippur.  The Mishna in Maseches Yoma lists 5 areas of pleasure that are prohibited on Yom Kippur.  The Gemara explains that this is learned from the fact that the Torah mentions the concept of inuy on Yom Kippur five times.

However, there are significant differences between the issur of eating/drinking and the other 4 prohibitions.  The punishment of “Kareis” applies to the prohibition against eating and drinking, but not the other 4 innuyim.

The Rishonim debate whether the other 4 inuyim are MiD’rabanan, or are all 5 considered part of the Torah’s explicit commandment not to partake in pleasure, no matter what form.  Obviously, there are many practical applications to this debate, as one can be lenient on Rabbinic prohibitions when there is a safek.  Practically, might it be permissible to wear leather shoes or bathe under specific circumstances?