I think multitasking is one of those words that has been used so much it has been reified. Ive never really thought it was a real thing outside of some careful and nonuniversal definition.
What is inside or outside the task of jogging differs depending on your goal for jogging. And what is central to your attention is also very fluid. same goes for listening to a podcast.. If your on a running machine, listening to Nerd poker, you probably wont miss any of the best jokes, if your running in a city crossing roads listening to 99pi you might not remember it all afterwards. sometimes I find moving while listening to something increases my recall because of the spatial associations made.
Multitasking is more like beeing in two meeting simultaneously and taking notes on both, writing a functional specification for a project while talking to your spouse about the weekly shopping list, talking with your coworker about a problem in a codebase while you work in _another_ codebase, trying to fix a production server while watching for cars on the road your kids are playing...
I wonder if it can be defined through System 1 and 2 activities. So doing a System 1 task + System 2 task simultaneously would be ok, but not doing System 1 task + another System 1 task.
I suspect the answer depends in part on how competent you are at the activity.
For example, if I'm learning to jog at a new cadence (180spm) I need to focus on just that. Once that's become my baseline I can listen to a podcast.
Similarly, if I'm at a stage of unconscious competence [1] driving to work, I can speak with a passenger. However, if it's a new section of road I'll need to pay more attention to signage, etc. at the cost of the conversation.
As for jogging, I think it depends on your goals but I generally wouldn't recommend listening to music or podcasts.
Instead, try to focus on yourself, your sensations, the smoothness/effectivness of your stride, cadence and so on. There is actually plenty to keep your brain busy.
It will help prevent injuries and make you a better runner.
I find the same while driving on motorways. Music is okay, but news / talk radio can sometimes distract me from what is going on and I lose situational awareness. Phone calls are right out.
I think you can generally do one physical thing on autopilot while still doing one mental task. Doing two mental or physical tasks at the same time is where it gets tricky.