The Download: ChatGPT workout plans, and cleaning up aviation

When I opened the email telling me I'd been accepted to run the London Marathon, I felt elated. Barely six months on from my last marathon, I knew how dedicated I'd have to be to keep running day after day, week after week, month after month, through rain, cold, tiredness, grumpiness, and hangovers. The marathon is the easy part. It's the constant grind of the training that kills you--and finding ways to keep it fresh and interesting is part of the challenge. Some exercise nuts think they've found a way to live their routines up: by using the AI chatbot ChatGPT as a sort of proxy personal trainer.