The faster you listen to a podcast, the more CPU/battery it will use.
But at soon as you pause the playback the app won't use anymore CPU/Battery.
Some users reported an issue where the app was using CPU/battery while being unused.
It looks like the Google Play Services used to display the ad banner at the bottom of the screen is responsible of this issue (ie: Samsung Galaxy S6, S7, S8)
Fortunetly there's a workaround.
You can replace the ad banner with interstitial ads in the app settings. Interstitial ads or more intrusive (full screen ads) but their are displayed once every hour (only if the app is in the foreground). Then there's not any more Google Play Service code running on every screen of the app, which solves the CPU/Battery usage issue.
Another solution is to buy Podcast Addict Donate to remove the ad banner but the previous free solution should work fine ;)
If for some reasons you still experience a high battery usage please go into the device Settings/Apps/Podcast Addict screen and Clear the cache.