Running News Daily

Strava's Most Active Runner Shared the Secret to Running 20-Mile Days at 61

"When people ask me about the key to my longevity, I tell them it’s slowing down."

Name: David B. Simon

Age: 61

Location: Agoura Hills, California

Occupation: Programmer/Developer (Retired)

In 2020, David Simon ran more than 8,000 miles and 2,000 hours—more than any other person on Strava, the popular fitness app. His run streak, however, predates the fitness platform by decades: Simon, turns out, has steadily clocked 20+ mile days for nearly 40 years. Men's Health talked to Simon, 61, about how he’s stayed motivated, consistent, and (mostly) injury-free.

I started running the summer after high school in 1977. Before that, I was a shy, insecure, and completely unathletic guy. My first run was to the local drugstore about a mile from home. I was completely exhausted when I got there, but it felt good. I ran home, and after that, I started doing it every day. Within a month, I was up to a continuous three-mile run without stopping. Three months after that, I was up to 15 to 20 miles a day and hooked.

At the time, I was able to do it within about two to three hours—these days it takes me about five. Running truly changed my life: I got fit, healthy, more confident, and happier. Now if I miss a day, I bounce off the walls. It’s become my version of meditation, an escape from real world pressures. Unless I need to travel for work or have an emergency, I’d never miss a day. I'd drive my wife nuts.

Now that I’m retired, I take my time. Often I’m doing work or taking personal calls, so the runs are partly my “working hours” too. I’ve been able to work from home all my life, which has afforded me more time to run while seeing my daughters grow up. Over the years, I've kept pushing myself. In 1984, I signed up for the first L.A. Marathon and finished in 4:20. I ran the next 10 marathons—and once in Chicago—and got my PR down to 3:20.

In 2013, I accidentally wound up running the Las Vegas Marathon. I was in Vegas for work, and after I got to my room, I changed and headed out for my run. When I got to the street, I heard what sounded like gun fire and saw thousands of people running towards me. Turns out, it was the start of the marathon, which runs down the strip and through downtown. So, I just started running with them and ended up finishing—okay, scabbing—the race. I felt bad when they gave me a medal, but they said it was okay when I fessed up, and I had a great time.

I later stopped running organized events—the crowds and logistics just got too hard with two kids. When my kids were in high school, however, they each wanted to run the marathon, so I did it two more times over those four years. They’re both still avid runners—and much faster than me, I might add. I wound up founding a youth cross country running team, the Calabasas Cheetahs, and coached them for a few years.

Even during COVID, I still wake up motivated to run—I’m quite addicted to running. I pretty much run by myself or only with my daughters, so I’ve been safe. I always use Strava and I like to do their monthly “running distance challenge,” which has a leaderboard. I’ve always been among the top runners, and I’m proud of that considering I’m also likely older than most of the other runners. Fortunately, living in Southern California means very few cold or rainy days.

f I’m not taking calls, I always run while listening to podcasts—mostly tech and security, or news and political podcasts. I also listen to Howard Stern on Sirius, as well as the occasional audiobook, but I don’t listen to music. Mostly I run in the mornings, but sometimes my schedule requires me to break up my runs. I’m very routine-oriented, and my routine is always to wake up, walk the dog, eat a small something, drink a Rockstar Energy Drink, and then head out for my run.

Diet is a very long story. I’m an extremely picky eater—healthy, but not diverse. I’ve never eaten meat, for instance. I’m not intentionally vegetarian: I’ve just never liked it.

I live on high protein power bars like ProMax, as well as healthy multigrain breads and carbs. I eat about 4,000-5,000 calories per day, and lots of carbs. I’ve been lucky with injuries, too: In 40+ years of running, I’ve only had one knee injury—I tore my meniscus. The doctor said I needed surgery, so I did it, and I feel like it was one of the worst mistakes of my life. That knee has never been the same. When I injured my other knee, I opted not to do surgery and it’s perfect now. You live and learn.

As for gear, I’ve used ASICS running shoes like the GT 1000 or Gel Nimbus almost all my life—they’re a little wider, which I need, and I’ve found them somewhat more durable without being heavy or clunky. I’ve tried others and they hurt my feet. I always carry my phone with me in a running pouch, and I use cheap bluetooth headphones with hooks and a cord. Since I’m only listening to podcasts, audio quality isn’t all that important. I mostly want something that’s comfortable and lasts a long time.

When people ask me about the key to my longevity, I tell them it’s slowing down. At my age, my “run” is more of a fast shuffle, but that also means less impact, so it’s good for my knees and body. I’m always breathing normally out of my nose and can talk easily unless I’m on a steep hill. That’s also what I like to tell beginners: Start slow. Build up. Don’t try to “boil the ocean all at once,” as a mentor once told me. Otherwise, you’ll burn out. Running is a lifestyle, not just a training activity.

My only goal this year is just to be able to keep doing what I’m doing. As I tell my family, when I can’t run anymore, I’ll walk. When I can’t walk, I’ll roll. And when I can’t do that, I’ll have to figure out a new activity.