Wednesday, twenty to seven

It's twenty to seven on a Wednesday evening and the doorbell goes. You're on the sofa with your feet up. You put one hand on the arm of the sofa, push, and make a noise as you stand. It's somewhere between a grunt and a sigh, and you've been making it for a year or two without deciding to.

The first three steps are the odd ones. Your hips feel as if they belong to somebody else, your lower back is set in the shape of the sofa, and one knee takes a moment to agree to bend. By the time you reach the front door you're walking normally. It's a parcel for next door. You take it in, go back to the sofa and sit down again.

You're fifty-four. You've noticed this kind of thing more and more. Getting out of the car after the drive home takes a moment of unfolding. When your grandson Alfie wants you down on the floor with his train track, getting down is fine, and getting up again needs a hand on the coffee table. At the multi-storey you take the lift for two floors, which you wouldn't have done at forty. Around three every afternoon your energy goes, and you get through to five on tea and whatever's in the drawer.

You have an explanation for all of it, and it's a reasonable one. You're getting older. You remember your father making exactly that noise when he got out of his armchair, and he was about the age you are now. It's what happens.

Here's the rest of that Wednesday, which you haven't thought about because there was nothing in it to notice. You got into the car at twenty to eight and drove thirty-five minutes to work. You were at your desk from half past eight until five. You ate a sandwich at the desk, because there was a lot on. From two until half past three you were in a meeting. Across the working day you were on your feet for perhaps forty minutes in total, going to the kettle, the printer and the loo. You drove home, sat at the table for dinner, and were on the sofa by seven.

Add it up. The car comes to an hour and ten minutes, the desk and the meeting room to not quite eight hours, and meals to forty minutes. The sofa, by bedtime, will be three and a half hours. That's a little over thirteen hours of sitting in a waking day of sixteen and a half. When the doorbell rang you'd been sitting since seven without a break, and before that since five with only the walk from the car to the house.

There's a woman at your work called Denise who's sixty-one. She walks a circuit of the industrial estate every lunchtime, in all weathers, and she takes the stairs. You've always filed her under "one of those people". It hasn't occurred to you that the difference between how she moves and how you move might have more to do with the lunchtimes than with the kind of person she is.

I'll use a few terms throughout. The tally is the number of hours you sit in an ordinary waking day. A long sit is an hour or more in a chair without standing up. A break is standing up and moving about for a couple of minutes. The age story is the explanation that your stiffness and tiredness are simply what your age brings. Disuse is what happens to a body that's asked to do very little, and it's the main rival to the age story in this book.

The habit has some regular features. This list is my own observation and not a research finding.

Nobody chose it. Each hour of sitting came attached to something else, such as a drive, a job, a meal or a programme.

It's invisible. You could tell me roughly what you ate yesterday and how long you slept. Almost nobody can say how many hours they sat.

The costs arrive slowly and look like something else. Stiffness, tiredness and a shrinking list of things you feel like doing are what you'd expect from ageing, so that's the label they get.

It feeds itself. The stiffer and more tired you feel, the more attractive the chair becomes, and the more time you spend in it.

And exercise, if you do any, sits in a separate box. You can go to a class on Tuesday and Thursday and still have a tally of thirteen hours on both days.

Try one thing before reading on. Pick an ordinary working day and work out your tally. Don't change anything. Go through the day from getting up to going to bed and add up the hours in the car, at the desk, at the table and on the sofa. Then note the longest single stretch you sat without standing up. Most people who do this find the total is two or three hours higher than they'd have guessed.