Rhythm is both a feature of and product of the phonological structure of English. The phonology of any language is a system, so that a change in one part of the system will affect some or all of the other parts.
Sentence stress is a difficult area to work on for learners and teachers alike. For this reason it's also an area which is often neglected, but this aspect of the language can cause problems for learners in both their speaking and perhaps more importantly listening.