"But I love my job"

Some readers will have felt that the last few chapters were about somebody else. You're not grinding through hours you resent. You like your work, you're good at it, and the evening session is often the most satisfying part of the day. It seems strange to be told to stop doing something you enjoy.

I take the point seriously. Enjoying your work is a great piece of good fortune, and I've no wish to talk you out of it. An absorbing job is one of the better things a life can contain. So let me separate two things that look alike from the outside.

One is working long because you're drawn to it. The other is working long because you feel uneasy when you don't. Researchers on overwork make this distinction, and they find the two have different consequences. Clark's review, from chapter 6, defined workaholism by the compulsion, the feeling that you ought to be working and the guilt and restlessness when you aren't. That inner pressure was tied to burnout and poorer health. Engagement, meaning real enthusiasm for the work, doesn't carry those costs in the same way.

There's a simple test for which one you have. Imagine a free Sunday with no laptop. If the picture is pleasant, and you'd happily spend the day on something else and pick work up on Monday with interest, then you love your job. But the picture may produce unease. You might already be thinking of reasons why this particular Sunday you really do need to look at a few things. If so, then something other than love is involved. Most people who work long hours and say they love the job have some of each.

And your body doesn't much care which it is. The evidence on long hours and health comes from studies that couldn't ask whether people were enjoying themselves. Mika Kivimäki and colleagues pooled studies covering more than six hundred thousand people in Europe, the United States and Australia, who were followed for an average of about eight years. Compared with people working standard hours of thirty-five to forty a week, those working fifty-five hours or more had a 33 per cent higher risk of stroke, and a 13 per cent higher risk of coronary heart disease. The stroke risk rose in steps. It was 10 per cent higher at forty-one to forty-eight hours, which was too small a difference to be sure of, 27 per cent higher at forty-nine to fifty-four, and 33 per cent at fifty-five and above.

On the strength of that and similar evidence, the World Health Organization and the International Labour Organization estimated that in 2016 about 745,000 deaths worldwide from stroke and heart disease could be attributed to working fifty-five hours or more a week.

I need to be careful here. These are observational studies, and a 33 per cent increase in a risk that's small for any individual in any year remains a small risk. People who work very long hours also tend to sit more, move less, sleep less and drink more, and it's hard to separate the hours from what travels with them. On mental health, Virtanen's team found that civil servants working eleven hours or more a day were about two and a half times as likely to have an episode of major depression over the following five or six years as those working seven or eight hours. That estimate comes from a modest number of cases and is imprecise. I'm not telling you that your job will give you a stroke or make you depressed. But your body registers the hours whether or not you're enjoying them, and your love of the work doesn't protect it.

If you love your job, the best case for a stop is the one at the end of chapter 8. People who switched off stayed engaged. If you want to be doing this work, and loving it, at fifty-five and sixty, you need the rest now.