Yes, to be alive breathing is required. However, how you breathe can aid or inhibit your ability to deliver a compelling and confident presentation.
Recently I was working with a young woman who had a tendency to do shallow breathing-she took breaths that only went as far as her upper chest. It gave the impression that she was gasping for air when she paused. This can happen when presenters are nervous. When people have shallow breathing like this it triggers a fight or flight response.
Start paying attention to how you breathe. Practice taking deep belly breaths. Put your hand on your abdomen to make sure you are doing it correctly. Your hand should rise and fall as your abdomen expands and contracts with each breath.
By breathing correctly, you reduce anxiety and have more breath to sustain the words you speak.