I wasn't always afraid of heights. As a kid, I climbed trees and swung from the monkey bars - and you did, too, didn't you? So what happened between ages 10 and age 40 that made me (us) incapable of standing on the edge of anything?

What happened was that somewhere along the way, I let fear close a door. And after it closed one door, it closed others, until I was not just afraid of heights, but afraid to ride my bicycle too fast, or even climb a ladder. "My life is fine without those things," I thought. Then, a botched surgery and a brush with death revealed to me that fear had been making my decisions for a very long time. I promised that if I could just survive the surgical aftermath, I would live life like there was no tomorrow.

Easier said than done. Armed with a second chance, I charged full-steam ahead, but my knees were knocking the whole way. Here are three lessons I learned about fear.

1. Fear and discomfort are two different things (but they often masquerade as the same).

We hate discomfort: the minute we feel our hands shake, or our hearts race, we say, "Oh, I can't do that, I'm too afraid." What we're really saying is "I'm choosing not to do this because I don't like the way it feels." We succumb almost right away to simple discomfort, and in doing so, never give ourselves a chance to be brave.

2. Don't try to overcome a fear.

Learn how to negotiate with it. It's entirely normal to be nervous when trying new things, especially those experiences that are physically challenging or a little dangerous. Acknowledge your fear. Talk to it. Tell it that you are aware that it's trying to hold you back, but you're still going to jump out of the plane. Then take a deep breath and do it!

3. Courage is a muscle.

And like every other muscle in the body, it must be exercised if it is to do the heavy lifting when life calls upon us to be brave. We must all find ways to strengthen that courage muscle on a regular basis.

If life's full experience is the wild and unstoppable arc of a pendulum, who wants to live in the middle? Pushing ourselves to the point of feeling fear, then shaking off discomfort and summoning courage, challenging ourselves in a way that makes us feel we might die - that is what it means to live.

At the end of our days, when we look back on our lives, what do we want to remember? A comfortable life lived in the middle? Facing fear, negotiating with it, winning now and then, means we live as we are meant to -- with gusto and uncertainty, and the occasional wild and breathless ride. But to be brave like this takes a lifetime of practice. It takes a promise, a pledge, to never, ever, let fear win.