How does the Audio Thread affect Main Thread?

Quick question here: How does the Audio Thread affect the Main Thread?

My intuition would be that if the audio thread takes less time than the main thread it won't affect ms per frame at all. The profiler presents the audio thread as if it's doing the work in the background and that it doesn't have anything to do with the main thread, but empirically it affects it very severely. If someone could shed some light on this it would be great!

 

Bump to this question. I don't use audio at all