Since the podcast is getting longer and longer, could you add chapter markers? Not only would this serve as a table of contents — which you can search later on, it’d make it easier to re-listen to a topic in case you wanted to catch more of the details. Plus, you can add links and custom artwork for each chapter, too, which is very popular with some podcasts. So if you talk about a particular study, the chapter marker could link to said study.
There seems to be decent software out there, too, e. g. Podcast Chapters.