Before you start

This is a short book and you can read it in two or three sittings. It's about one habit. You need to get somewhere close, and your hand goes to the car keys or the lift button before you've thought about it. The shop half a mile away. The office on the second floor. The school six hundred yards up the road. Your legs could cover the distance, and they don't, and you don't experience that as a decision, because it isn't one. It's a default.

I'm going to argue three things. The first is that the default makes sense from the inside. The car is right there, the lift is right there, the weather is what it is, and you've got things to carry and not much time. The second is that most of the reasons don't survive a look. For short trips the car often loses on time once you count the keys, the parking and the walk from the space. Walking at an ordinary brisk pace is what the NHS calls moderate activity, the kind that counts, and the biggest health gain from walking is at the low end, between none and a little. And the time isn't lost. It's moved, and it comes back with something attached. The third is practical. You set a line, a mile and three floors to start, and below the line you walk, unless you've got a reason you'd say out loud. Chapters 19 to 21 cover how.

This book doesn't ask you to sell the car, take up hiking, buy a step counter or hit ten thousand steps. It asks you to use your legs for the distances they were already going to cover, and to notice how many of those there are.

Three cautions.

The NHS says that if you haven't been active for some time, or you have a medical condition, you should speak to a GP before starting. A mile of walking is gentle, and for most people it's nothing to check. But if you're not sure, ask.

If walking a mile or climbing two floors brings on chest pain, or breathlessness that's out of proportion, or dizziness, stop and see a GP. Chest pain that doesn't go away is 999.

And if a mile isn't a distance your body can cover, because of joints, a heart or lung condition, a disability, or age, the line in this book is yours to set, with your GP if you'd like, and the argument holds above whatever line you choose. Nothing here is about people who can't walk. It's about people who can and don't.

The notes at the back give my sources and their limits. Where I'm giving my own reasoning and not a finding, I'll say so.