4 Months Into Running - Jonathan Chrisnaldy

Four months ago, I had never run more than 5 KM. Last week, I ran around Manhattan Island. Here is what running taught me about the power of mindset.

Cardio fitness (VO2 max) chart trending upward over six months — Six months of cardio fitness (VO2 max), trending up.

From the gym to the pavement

As someone who sits in front of a laptop 11 hours a day, working out is a must to keep my cortisol levels in check. When I was in Indonesia, I never ran more than 5 KM because of the pollution, the heat, and the lack of pedestrian access. During my time at Columbia, I usually went to the gym three to four times a week, but I rarely did any cardio.

In March 2026, I started running with a colleague, and it turned out that I genuinely enjoyed it. Over time, running increased my VO2 max, which is associated with greater longevity and a reduced risk of cardiovascular disease. Even in everyday life, I noticed that I rarely got tired anymore.

An impulsive half marathon

In April 2026, on a bit of an impulse, I signed up for a half marathon, of course with proper training and nutrition. Once again, thanks to my colleague who supported me from day one, I managed to finish the race in under two hours.

Half marathon stats: 21.51 km, 1 hour 55 minutes, 5:21 per km pace — My first half marathon: 21.51 km in 1 hour 55 minutes.

What I came to realize was that because my preparation was not ideal, my body could not handle the stress very well. But my mind kept telling me that I could do it. And I did. I finished in under two hours. Afterward, however, I could barely walk home, and I even requested to work from home for a day because climbing the stairs was too painful.

Holding the half marathon finisher medal at the race — Medal in hand at the finish line.

“If your mind can handle it, you can control everything.”

Running around Manhattan Island

Four days after the race, I was back for a recovery run, just 5 KM around the neighborhood. Then on Saturday, the impulsive thoughts returned when a friend asked me to do the Manhattan Loop, which means running around the entire Manhattan Island (55 KM). I knew it was impulsive and probably not a great idea, but once again, I chose to believe in the power of mindset.

Strava map of the Manhattan Loop: 55.14 km in 8 hours 8 minutes — The Manhattan Loop: 55 km around the island in just over 8 hours.

So on Sunday, exactly one week after the race, I ran around Manhattan Island at a slow but steady pace, and we finished in eight hours. It was painful for my legs, but it was fun, and I will probably do it again. More importantly, it reshaped my mental model and the way I see the world. For me, there is nothing wrong with continuing to believe in yourself while you can, as long as that belief is channeled into something positive.

Group selfie with friends after the Manhattan loop run — With the friends who got me through every mile.

So keep sweating, everyone.

— Jonathan