Shouting makes me hoarse -- how does Hillary keep it up?

I'm not the only one who noticed how much Hillary Clinton shouts. See Hillary just can’t stop yelling where Thomas Lifson notes the irony when Hillary says, “We’d be a lot better off if we actually talked to each other instead of yelling at each other.” Yet she does an awful lot of shouting herself.

How does she keep it up? Is there a way to shout and prevent hoarseness? Otherwise she may lose her voice entirely.