Just Build Your Stamina

1. AI got smarter. We got more worn out.

I started using Claude Code for real work last December. I pushed it across the whole company, to the point where it was close to mandatory, and these days I handle most of my own work with AI too. It answers my emails, posts to social media and analyzes how people react, keeps meeting notes up to date, and applies AEO (answer engine optimization) to our blog. You write one prompt and the AI does it right there on the spot. Of course your brain floods with dopamine.

The problem is that humans have a limited attention span. When you run several things at once, at some point you start wondering what on earth you're actually doing, and your head starts to throb. I now understand those news stories about someone collapsing after 48 hours of gaming at a PC bang (a Korean internet cafe). I've read a lot of posts lately saying AI is actually leaving people more drained, and honestly, the people on my team are no different.

So these days I use Cowork as my main tool instead of Claude Code. It gives you less freedom than Claude Code and it's a bit slower, but that turns out to be an advantage: I can keep only as many windows open as I can handle and work through tasks one at a time. For a non-developer like me, this may actually be the more efficient setup. (If you're not building many programs yourself, you don't really need Claude Code.)

2. Your body rules your mind and heart

One way to deal with the AI era is to take it head on. Learn to code, build agents, push automation to the limit. That matters a lot, and it's meaningful work. At the same time, it's also important to look squarely at what AI can't give you and make up for it yourself. Here's what I mean.

My wife loves "Misaeng", a hugely popular Korean webtoon and TV drama about a former Go prodigy who ends up as an office intern. One day she read me this line from it:

"If there's something you want to achieve, build your stamina first. If it's something you think you'll be doing for the rest of your life, build your stamina first. Laziness, idleness, boredom, irritability, depression, anger. They are all symptoms of a body that can't hold up, so the mind ends up ruled by the body. The reason you often fall apart late in the game, the reason you're slow to recover after taking damage, the reason you're slow to bounce back after a mistake: all of it comes from the limits of your stamina. If you want to win, first build a body that can endure enough thinking. Without the protective shell of stamina, 'mental strength' is nothing but a slogan." Yoon Tae-ho, "Misaeng"

It convinced me the moment I heard it. People say mental strength is what counts, but in reality physical stamina governs mental strength. If your body can't hold up, no amount of willpower is more than a slogan. The line comes from the world of Go, yet I can't think of anything more accurate for office workers in the age of AI.

3. Life is a long run, after all

I don't think of myself as someone with great stamina. Still, when I was young I could keep going and pull all-nighters without a second thought. These days, if I push even a little too hard, I definitely pay for it the next day. But life is a long marathon. To keep moving forward while riding the roller coaster of ups and downs, growing, learning, and taking hits and landing a few of your own, what you need in the end is stamina.

As I get older my stamina will keep dropping and more things at work will blow up. AI will help carry some of that, but in the end what holds it all up is this one body of mine. So I have to take care of my own body. AI can't do that for me yet. (Neither can it do childcare, the dishes, or the cleaning. There's still so much AI can't do for us, haha.)

By the way, my mother, who is in her mid-sixties, has recently been working out almost six days a week, mixing Pilates with personal training. She never exercised at all in her life, and now that she works out one to two hours a day, she says her vitality has come back and she's full of energy. It amazes me how much she's changed.

Then my mother asked my younger sister, who works as a designer in New York, in all seriousness: "Your English is good. Why don't you become a Pilates instructor who teaches in English in Hannam-dong?" (Hannam-dong is one of Seoul's wealthiest neighborhoods.) At the time, my sister and I both said, what are you talking about. But now I quietly think it makes a lot of sense. Well-off families in Hannam-dong are going to keep their kids exercising regularly anyway, and they'll want them learning English too, and there probably aren't many places in Korea that do both at once. Of course, if someone says "AI will end up doing that too," I don't have much of a comeback. But at least for now there's clear demand, and above all, teaching exercise would also build her own stamina. So I came around to thinking it isn't such a bad idea.

Orchestrating AI agents well matters a great deal. But even to do that better, we can't let our guard down about the fact that we're still human. (We're not humanoid robots yet.) So the first thing to do in the AI era might be surprisingly simple.

Just build your stamina.

I'm not an AI expert, but I'm always up for a coffee chat. If you'd like to share your story or hear more about other people's experiences, reach out on LinkedIn.

Originally published in Korean on Brunch, March 20, 2026.