"I can't keep getting up, I've got work to do"

The strongest practical objection comes from the working day, because that's where most of the tally is and where you have least control. You're paid to get things done. Getting up every half hour sounds like a way to get less done, to lose your thread twenty times a day, and to look as if you're avoiding work.

Take the worry about looking idle first, because I think it does more to keep people in their chairs than the work itself. In most offices, sitting still at a screen is what diligence looks like. It's worth noticing that it's only a look. You know from your own experience that an hour at the desk can contain twenty minutes of work, and that the answer to a problem often turns up on the walk to the kettle. Most colleagues, in any case, are paying far less attention to your movements than you imagine.

On whether breaks damage work, the best evidence I know is a large British trial. Charlotte Edwardson and colleagues worked with 756 desk-based council employees in Leicester, Liverpool and Greater Manchester. Whole offices were assigned by lot to one of three arrangements. Some got a programme to help them sit less, with coaching, prompts and small changes such as moving the bins and printers further away. Some got the same programme plus a desk that could be raised for standing. The rest carried on as usual. A year later the researchers measured everyone's sitting with sensors.

The programme alone cut sitting by about twenty-two minutes a day. The programme with the desk cut it by just over an hour a day. Both groups reported small improvements in stress, wellbeing and vigour compared with the offices that carried on as usual, and the desk group reported less pain in their legs and feet. The researchers measured work performance too. The published summary mentions no harm to it and no boost either, so I won't claim one.

So across dozens of real offices, people who sat an hour less each day felt somewhat better and their work didn't visibly suffer. That fits what most people find when they try it. A two-minute break at a natural pause costs you very little concentration. It can help, because long unbroken hours at a screen are when your attention goes soft, and you begin rereading the same paragraph.

The trick is to attach breaks to things the work already contains, so that they don't feel like interruptions. These are suggestions and you'll think of better ones for your own job.

Take phone calls standing up, and walk about if the lead or the signal allows. Many people think more clearly on their feet during a call anyway.

When you need to ask a colleague something, walk over and ask. It's often quicker than the exchange of messages would have been.

Use a smaller glass or mug. You'll refill it more often, and the refills will look after the other end of the process too.

Finish a task, stand up, then start the next one. The gap between tasks is a natural break, and you were going to lose a minute there regardless.

Use the furthest printer and the loo on the next floor, as the Edwardson programme arranged for people. It's the same errand, with forty more steps in it.

In a long meeting, say at the start that you'll stand at the back for part of it because it helps your back. Nobody minds, and often somebody else joins you.

And eat lunch somewhere other than your desk, even if it's only ten minutes on a bench. On the Wednesday in chapter 1, a walk to a bench and back would have been the only proper movement between half past eight and five.

Some jobs allow almost none of this, among them driving, call-centre work under a headset and a timer, and operating machinery from a seat. Chapter 15 deals with those. In that kind of job the breaks have to come at the edges of the working day, which makes the evening matter more.