"I'll catch up at the weekend"

Sunday afternoon is when you get ahead. The house is quiet, nobody's emailing, and two or three hours at the kitchen table takes the edge off Monday. It feels like the most productive time of your week, and it seems a small price.

The munitions records have something to say about this too. The wartime committee was particularly critical of Sunday working. Its verdict, which Pencavel quotes, was that seven days' labour only produces six days' output, and that cutting back Sunday work had caused no appreciable loss of production. Pencavel tested the claim with the committee's own data. He compared weeks in which the same total hours were worked with and without a day of rest. The weeks with no rest day produced about 10 per cent less. It was the same number of hours, and the only difference was whether the workers had had a day off.

That's a finding about recovery. People aren't machines that produce at a fixed rate per hour of operation. They run down and need restoring, and the restoring takes continuous time away from the work. An hour of work done on a rest day has to be paid for out of the week that follows.

The modern research on this uses the term psychological detachment, which means mentally switching off from work during your time off. It's more than being physically absent. You can be at your daughter's gala with your mind on the rota, and that doesn't count. Sabine Sonnentag and colleagues followed 309 employees in demanding service jobs for a year. High job demands predicted more emotional exhaustion and more physical complaints a year later, as you'd expect. But people who detached from work in their off-hours were less exhausted a year on. Among people with high demands, those who switched off were protected against the rise in physical complaints and the fall in engagement with their work that the others showed.

That last finding deserves attention. The people who switched off stayed more engaged with their jobs. Detachment was what kept them keen over the long run. The ones who never switched off were the ones whose enthusiasm wore away.

Now look at your Sunday. The two or three hours at the kitchen table are the visible part. The less visible part is that Sunday working means you never have a whole day without work in it. From about eleven on Sunday morning you're aware that the session is coming. Your mind starts to turn towards Monday. Your weekend is really a day and a half, and you spend part of that thinking about work. You'd noticed this on holiday, when it took you until the second Wednesday to stop checking your phone. A mind that hasn't switched off for years takes more than a week to learn how.

The objection is that Monday is genuinely easier after a Sunday session. I believe you. But Monday is easier after any good preparation, and twenty minutes on Friday afternoon, writing down the first three things for Monday, gets you most of that benefit. What the Sunday session mainly relieves is the unease of not working. The habit created that unease, and the session brings it back by the next weekend.