Anxiety and unsteady breathing are the culprits that exacerbate a stutter. We have stutters, we anticipate stuttering which triggers fight or flight and tight breathing which makes our ability to compensate for the neurological misfires plummet. Humans are constantly in a state of hyperventilation. Lifting is probably a great way of gaining breath control and confidence but I’d say one could get equal benefit from yoga or running or MA… whatever floats their boat.