When I was in high school, one of my classmates ran a marathon without training for it.
I thought she was insane. In fact, I knew she was insane. She told of chafed armpits in the first 10 miles; a torrential downpour for miles 10 through 15; wet, heavy cotton until the sun came out at mile 20; blood and pus seeping from her blisters into her socks until mile 26.

The day she came back to school, she took her time on the stairs, gingerly lifting one leg half an inch off the floor and then shuffling her body toward the next step with a wince. At lunch, we bombarded her with questions: how had she willed her legs to keep moving? How had she not died of thirst and exhaustion? How had she run through bursting blisters? Most of all, why hadn’t she just stopped when she became unbearably exhausted?
“I needed to prove to myself that I could do it,” she answered with a look of whimsical triumph in her eye.

It wasn’t until I started running myself that I understood that urge. I still will avoid chafed armpits at all costs, but now the prospect of discomfort doesn’t freak me out. Let me elaborate.

Until I started running, I was very pain-averse. I knew that without pain I would not gain, but I didn’t particularly care about gaining anything except an excuse not to run. The moment my leg muscles began to burn, I was ready to roll onto the ground and be carried home. Whenever I ran more than a mile or two, I felt as though I was going to die, or at least as though I deserved a congressional medal of honor. I was also highly sensitive to extreme temperatures, making anything other than swimming hellish. The idea of sweating was unspeakably scary. Sweating was for athletes. Sweating was also for the unkempt, the classless. Until I started running, I thought that it was plausible that I did not have sweat glands.

When I was younger, my school required us to run a mile to pass Physical Education (P.E.). I pleaded with my father, who was also my P.E. teacher, not to make us run it; I presented a logical argument and thought about drafting a petition. It was no use: running the mile was a state regulation.

I dreaded waking up the day of the run. I considered pretending to be sick, but then remembered that if I missed the science lesson on meiosis, I would probably never catch up and be forced to drop out of school (it was seventh grade, after all!). So I dressed carefully, with the fact that I might be perspiring in mind, and bravely went to school. My school didn’t have its own track—it was in Manhattan, after all—so we walked the six blocks to Asphalt Green, a YMCA of sorts on 90th Street and East End Avenue, as a cluster. Then we began to run. The overachievers sprinted as fast as they could and then sprawled on the asphalt, comparing times. The middling crew was the next to finish. Finally, the stragglers huffed and puffed to a stop.

Then there was me and my friend Amari. We had talked about it beforehand and decided to walk the mile instead of run it, which was legal because nobody told us that we couldn’t. It was a beautiful day outside, and because we weren’t out of breath, we shared some good conversation in the 13 minutes that we spent circling the field four times. “Why would anybody run when you could just walk?” I wondered. When we stopped, my P.E. outfit was as fresh as it had been before. I felt triumphant and clean.

I hardly ran again until my senior year of high school, when I decided to see what would happen if I broke a sweat. It’s hard to say what compelled me to wake up, lace up, and trot down the street, but whatever it was, I haven’t looked back. (I literally haven’t looked back, because I don’t trust my balance, and swiveling my neck while jogging would probably end in catastrophe).

It’s hard to explain why running is so glorious, but much of it has to do with pain, just like my insane, marathon-running friend said. Confronting discomfort minute after minute, run after run, day after day, asks you time and again whether you’re going to be strong or weak. It asks you if you’re going to be a sitzpinkler (a wimp) or a winner. Running is not hypothetical.

There’s nothing better in this world that I know of (except for chocolate) than running on smooth pavement on a spring morning while listening to “Centerfield” by John Fogarty. I feel young and alive! My body was made to move!

However, free-flowing endorphins come at a price.

First, I fear that my feet will never be the same. “The same” here is a euphemism for “not atrocious.” At any given time, at least three of my toenails are ambivalent about whether or not they want to stay attached to my feet. I’m O.K. with that, actually. I’ve always thought it was overkill to have 10 toenails.

Second, even though I will always want to talk about the run I’ve just done, chances are that approximately zero other people in the world care. That’s O.K., too. Running isn’t a comparison or a competition.

Finally, I’ve found that smiling while running is a surefire shortcut to less pain. So is wearing pink, a color of good health and good cheer. I’ve found that these two phenomena make me look rather insane. So if you’re ever in the gym and see someone running in all pink, smiling (and, in all likelihood, huffing and puffing), it is probably me. It’s just as well: perhaps it sends the message that I am not one to be messed with.

Running does make me feel that I am not one to be messed with. It makes me feel pretty invincible.

It doesn’t matter how fast or how long you go. But it’s important, sometimes, to just go and see what you can do. Your body can stand almost anything. Why not let it?

Davis is a member of the class of 2017.