Ich habe mit ChatGPT für den Paris-Marathon trainiert

*Derek Wallbank for Bloomberg News*

Twelve months ago, I signed up for the Paris Marathon. Within six months, I knew I’d be in trouble without a trainer. So, living in the San Francisco Bay Area — the home of artificial intelligence — I decided to build one myself.

Like many runners, I’d signed up for the marathon in a post-race haze of glory. At the time, I was living in Singapore and running almost daily in the tropical heat. A recent half-marathon in Hong Kong had gone well; I posted a personal best of 2 hours 47 minutes. I’d even joined a weekly running club, spending Tuesday nights circling a track with 100 other Singapore Falcons. My only previous marathon, more than a decade earlier in Washington, DC, had fortunately faded into memory: a seven-hour finish, blown-out hips, knees and feet, and a limp that lasted weeks.

In April 2025, anything seemed possible. Then I relocated to California in June for a new job. Work and family adjustments took over, leaving me little time to train. My fitness slipped, the weight crept up, and by October it was clear something had to change.

I’d been experimenting with ChatGPT and, in a mix of curiosity and desperation, entered a prompt: “Good evening, I am Derek, and I want you to act as my expert running coach and nutritionist. Your mission is to get me in the best shape possible to achieve my next goal: the 26.2-mile Paris Marathon on April 12, 2026.”

[Read the full essay here.](https://www.bloomberg.com/news/features/2026-04-10/training-for-a-marathon-with-an-ai-coach-what-worked-and-what-didn-t?accessToken=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzb3VyY2UiOiJTdWJzY3JpYmVyR2lmdGVkQXJ0aWNsZSIsImlhdCI6MTc3NTg0Mzg2OSwiZXhwIjoxNzc2NDQ4NjY5LCJhcnRpY2xlSWQiOiJURDk5SzRLSVAzTFAwMCIsImJjb25uZWN0SWQiOiJEMzU0MUJFQjhBQUY0QkUwQkFBOUQzNkI3QjlCRjI4OCJ9.58Zm4vydK14YAc_YjKtgHUy8R86mT-SHinY0q0_HLeU)