The challenge and energy running requires may be a selfish one, but it actually motivates me to be stronger in my relationships.

Fall in love with running and you won't get sick of it – you won't be someone who used to run years ago – or someone who wishes they had the motivation to run but just can't seem to bring themselves to do it. You have to be IN LOVE with this sport to keep doing it month after month, year after year – even when the going gets tough. That's what it's like for me and running – it's a till death do us part type of relationship.

Some people live to run. I don't believe that anyone should live their lives as if they have nothing else (but running). I run because it makes me feel real. On top of the pain and the thrill and exhilaration, running makes me feel alive. I don't live to run, I run so I can live.

Running is alone time that lets my brain unspool the tangles that build up over days—work-related grief, everyday family-life frustration, and the occasional bit of deeper-seeded crap that gets labeled depression and the like. I run, pound it out on the pavement, channel that energy into my legs, and when I'm done with my run, I'm done with it. I'm a happier and healthier person now.

Why run? I run because I am an animal. I run because it is part of my genetic wiring. I run because millions of years of evolution have left me programmed to run. And finally, I run because there's no better way to see the sun rise and set... What the years have shown me is that running clarifies the thinking process as well as purifies the body. I think best – most broadly and most fully – when I am running.

After running a few marathons I can explain to people why I run. It calms me. I can't imagine not having it in my life. It helps me to sort through things. It's like stepping outside myself and getting a better perspective of who I am. Running helps me focus better, helps me take my life in the direction it needs to go. It's not like I concentrate on these topics while I'm in the process of running, but running opens my mind to all kinds of possibilities and perhaps the solution is out there waiting for me to find it. Running takes me to that place.

That's the year when, as a ninth grader, I started running. Immediately I was enamored. I loved the sense of exploration, of challenging myself, of being outside in all kinds of weather. I loved the time alone, time to think about whatever came to my head. I loved seeing if I could go farther than I ever had, or run a loop faster than I did the week before. I loved how I felt physically while running and how I felt mentally when I was done. When I joined the high school cross-country team that fall, I learned to love running even more. Training with friends, racing against those friends, building toward a long-term goal – all this and more about being a competitive runner added a whole other layer of attraction to this most natural act.

The number of miles I have run since I was a toddler would have taken me around the world several times, and I still cannot define precisely my joy in running. There is no sacrifice in it. I lead what I regard a normal life. In my case, I thoroughly enjoy running 100-odd miles a week. If I didn't I wouldn't do it. Who can define happiness? To some, happiness is a warm puppy or a glass of cold beer. To me, happiness is running in the hills with my mates around me.

Daily exercise dosage: thirty minutes of elevated heart rate, taken daily, a magic bullet against the ills of modern life. That's actually how running starts for most of us. If we progress beyond that formula, it is because we discover an appetite that turns running into something more: a challenge, a security blanket, a fulfillment unavailable in otherwise sedentary lives. Dr. Kenneth Cooper has said that if you're running more than fifteen miles a week, you're running for something other than cardiovascular health. Yes. Exactly.

As I get older I see that running has changed for me. What used to be about burning calories is now more about burning up what is false. Lies I used to tell myself about who I was and what I could do, friendships that cannot withstand hills or miles, the approval I no longer need to seek, and solidarity that cannot bear silence. I run to burn up what I don't need and ignite what I do.

For the most part, we exist in a numb, dead society. I'm doing my best to be alive and running in the mountains is the best way I've found to do that. And because I love the effortlessness that sometimes occurs while cruising down a cushy pine-needle singletrack or even while grinding up a switchback above tree line. I love how I can run up and into a mountain cirque or over a pass and be completely dwarfed and humbled by the sheer immensity and grandiosity of the landscape and I love flying down the other side with the breeze in my hair and the gravel in my shoes and the burning in my quads and the branches in my face and then when I'm finally all worn out there's nothing like peeling my shoes off and just sitting. Just being at rest. Running sharpens the focus on life and intensifies the emotions. Is there any better reason to do anything?

What distinguishes those of us at the starting line from those of us on the couch is that we learn through running to take what the days gives us, what our body will allow us, and what our will can tolerate.

The first person you have to inspire every day is yourself. Running will do that. We're all terrible at something. Why not make up for it with a strenuous, completely unrelated activity? When you're nothing but a slob at the desk, you can instantly turn yourself around with a quick run. I've never been in a ditch so low that a run wouldn't pop me out of it. There are no shadings in this. Every run makes you fantastic.

Running focuses my mind and allows me to think around a subject. I still need a workshop to make discoveries, but on a run I might think of a new avenue to explore. Another thing I learned from running is that the time to push hard is when you're hurting like crazy. The moment you should accelerate is the moment you're the most tired. I found that to be so in life as well.

Running has made being depressed impossible. If I'm going through something emotional and just go outside for a run, you can rest assured I'll come back with clarity.

I have also taken up running, something I gave up years ago in the wet, gloomy darkness of Portland. But I don't run because it's sunny here almost every day, and I don't run because there are more perfect bodies in Los Angeles than I have ever seen in my life. I run because I can.

And I run because, as my feet meet the sidewalk, I digest my life changes and discover new lines for my stories, and as the palm trees tickle my peripheral vision, I dream.

And I run because as I count down the blocks in descending order — eighteen, seventeen, sixteen — I know when my feet land on block one, my eyes will be rewarded with the most humbling stretch of the Pacific Ocean. Some days I stand on the path above the beach, taking in the endless kingdom of liquid blue. Some days I run down the slope and over the bridge onto the sand, to smell the water and listen to the waves moving toward and away from the land.

Then, I remind myself to stay in the fight, while I surrender to this view.

The focused, calm, and vital feeling that occurs with my daily runs is more a constant companion than the intermittent guest of the runner's high. My daily run has been one of my closest friends for over 40 years. It's helped me solve problems, guided me to some great ideas (as well as some ridiculous ones), accompanied me to the heights of ecstasy, and has humbled me on many occasions. It's been there after births and after deaths, after joy and after sorrow. But over my long running career, I can recall only a handful of times that I've gone beyond the more standard 'in the zone' type of feeling and experienced a true runner's high. Those few occasions have left me with blissful elation, experiencing a running rhapsody as though gliding on air with a flowing, effortless, and exultant feeling.

Running is not just about fitness and competition; it's about changing our lives. Most of us run because it makes us feel significant, powerful, and in control, not just because we want to compete. When people who have never had a sense of accomplishment before suddenly gain it, it transforms every aspect of their lives. They become increasingly fearless. People always realize they can do more when they first do something at all. Confidence grows, and with it, so does vision.

Marathon running is a sport of goodwill. It's the only sport in the world where if a competitor falls, the others around will pick him or her up. It's the only sport in the world open to absolutely everyone, regardless of gender, age, ethnicity or any other division you can think of. It's the only occasion when thousands of people assemble, often in a major city like New York or London, for a reason that is totally peaceful, healthy and well-meaning. It's the only sport in the world where no one ever boos anybody.

Every runner has a story about that race (or training run) that was a disaster. They wanted to quit; they wondered why they started or signed up; they doubted their ability to finish, let alone hitting that goal time. They talked about the conversations, the mental arguments that sometimes occur daily...

Don't be afraid of running. It does love you — even when you hate it. It loves you so much it doesn't coddle you or lie to you. If you don't train, you suffer. And sometimes you suffer even if you've done everything you can to prepare. Running will remind you of your life most days — unexpected headwinds, devastating injuries and disappointing performances.

But if you really commit to it — even smaller distances like a couple of miles a few times a week — it will transform you. The sport that most people say they hate will reveal aspects of you, of your abilities, that you never would have known if you hadn't decided to get out and just run. One day you'll wake up and instead of having that argument about whether or not you want to run, you'll ask yourself how you lived without the run. It becomes the best part of your day and creates the best friends and best moments in your life. All you have to do is put one foot in front of the other even when it seems hopeless, pointless and impossible...

The reasons to run are as numerous as the runners on the road. But my favorite aspect of running is how the sport seems to transform difficult moments into inspiring opportunities.

That hill, that headwind, that unexpected detour — they're all just opportunities to see something different in ourselves, in others and in the world around us.