Next, tonight, the search of the secret of changing your life. Last night, our Dan Harris told you about a panic attack on live TV. And it was the wake-up call that started him asking big questions... See More
Next, tonight, the search of the secret of changing your life. Last night, our Dan Harris told you about a panic attack on live TV. And it was the wake-up call that started him asking big questions about the way we can all get more control of what really makes us happy. Tonight, Dan brings the simple answer he found. And it takes only five minutes a day. From ABC news, this is "Good morning America." We're going to go, now, to Dan Harris, who is at the newsdesk. Dan? Reporter: This is me ten years ago, having a panic attack on "Good morning America." It's too early to prescribe statins. Reporter: My heart is racing, my palms sweating. I literally cannot breathe. This meltdown was all, I later learned, brought on by a personal struggle so many of us face, a combination of doubt, drive, depression and drug abuse. So, I went in search of something to tame my racing mind, interviewing a gaggle of gurus. From the questionable, like the positive thinker, Joe Vitale, who charges 5 grand for a ride in his rolls. You never wake up in the middle of the night thinking how am I getting away with this? No, never. Reporter: To successful and mainstream figures, like deepak Chopra, who I just couldn't connect with. The nanotech workshop in the mind of god. Reporter: That's where it gets difficult to understand. Why? Reporter: But all along, there was a simple way to defang the voice in our heads. Something this fidgety, skeptical reporter always considered to be uniquely ridiculous. Meditation. Just breathe. Reporter: But then I found out that millions of Americans are doing it. Including lots of successful people. From the co-founder of Twitter, to pro athletes like novac djokavic, to the U.S. Marines, to Dr. Mehmet oz. The ability of stillness, of the deafening quiet of meditation, has endless benefits. And it allows you, perhaps for the first time, to realize that those dangerous voices you hear telling you that you aren't good enough, are lying to you. Reporter: I never thought I'd do this. But I'm about to give a medication lesson on national television. There are three steps. Number one, sit upright. It doesn't have to be cross-legged. You can do it in a chair, on the floor, whatever. Two, just try to feel you're breath coming in and going out. And three, whenever your mind wanders, which it will a million times, simply return your attention to the breath. Think of this act of repeatedly hauling your attention back to the breath, like a bicep curl for your brain. Even if it's just five minutes a day. Brain scans show meditation can literally grow the gray matter in the parts of your brain associated with self-awareness and compassion. Short, daily doses of medication. And shrink the area associated with stress. And as Dr. Oz explains, that's not all. Medication doesn't just help with blood pressure, which it does. It doesn't just help with things like psoriasis, which is an autoimmune disease of your skin. How can meditation help that? Because it changes how your body innately responds to the world outside of it. Reporter: So, what's it done for me, the guy who once had a panic attack in front of 5 million people? Medication has helped me slow down that the good stuff in my life has become much more vivid. From the fact that ABC news lets me be the co-anchor of "Nightline." To eating cookies with my wife. To playing with our cats, even if they don't like it as much as I do. So, Dan, you and I talk about this a lot. Yeah. But five minutes. Yeah. I say five minutes. Everybody has five minutes. Nobody's so busy they can't do five minutes. And I saw benefits right away. Chief among them, I was able to focus on what's going on right now instead of being lost in memories of the past and fantasies about the future. Why only 10% happier? It's slightly tongue and cheek. But anybody on Wall Street will tell you 10% is a good return on investment. And athletes say if you can be better 10%, you win. You're going to have more on "Nightline." So many people are weighing in online with you to talk about this. And you can read about his experience in the new book "10% happier."
This transcript has been automatically generated and may not be 100% accurate.