Few acts are a divisive as public speaking, as half of us want to be on the big stage and half of us want to stay away from it as much as possible. As Jerry Seinfield once observed, more people fear public speaking than death: "If you had to be at a funeral, you'd rather be in the casket than doing the eulogy."

Here's a secret, though: Professional public speakers know a bunch of things that people avoiding the stage do not understand. As I've done more speaking, I've discovered some fascinating knowledge most people don't realize.

You should be sick of your talk well before you give it: Speaking coach Dr. Michelle Mazur says it best: The best speeches are practiced, refined and memorized to the point where you are exhausted of hearing them! It is counterintuitive - you'd think keeping it loose would help you stay fresh on the stage - but a few great things happen when you do heavy rehearsal.

First, you remember the talk, which means no notes or teleprompter is necessary. Second, you don't worry about remembering the talk, so you are fully present when you are communicating to the audience. Third, you have gone over the talk repeatedly, excising as many rough spots as possible. You have set yourself up for a smooth, professional experience.

Public speaking keeps you fit: You are in constant motion, shaking off nervous energy, gesturing to make a point and often walking to help occupy the stage. Public speaking is as physical as it is verbal.

I recently did a talk about productivity at the popular southern startup incubator American Underground. Sure enough, my Apple Watch was buzzing as I wrapped up my hour-long talk. My daily exercise was already done - and it wasn't even lunchtime.

On The Tim Ferriss Show, middle-age speaking guru Tony Robbins shared his intense physical regimen for keeping up with his all-day, week-long seminars. It is a marathon. If you have any interest in burning calories, then lots of public speaking will kill two birds with one stone.

Money isn't the only way you can be taken care of: It is easy to assume that the speaker in front of 15,000 people has gotten paid more than the one talking to 150 folks, but that's not true at all. What you get paid is based on several factors, including your negotiation skills, the money available to the organizers and your potential popularity with the listeners.

The ways you can be taken care of is pretty broad, too: A free ticket for speaking at an expensive conference, books purchased from you for all the attendees or exclusive access to an audience interested in your services.