WE SUGGESTED in a previous blog post that working shorter hours might be good for your productivity. It may also be good for your health. The graph below shows the relationship between working hours and "potential years of life lost" (PYLL), both of which were taken from the OECD. PYLL is a measure of premature mortality, which estimates the average number of years a person would have lived if they had not died prematurely. It gives more weight to deaths among younger people and may therefore be a better measure of mortality. The higher the value of PYLL, the worse.

We display the results in the simplest possible way: as a scatter graph. Nonetheless the data, which go from 1970 to 2011, are a little alarming:

Longer working hours seem to lead to higher premature mortality. (For stats nerds: the strength of the relationship is significant, with an r-squared of 0.2). The implication that over-work is bad for you chimes with lots of research (such as here, here and here) which links long working hours with poor health. Stress, for example, can contribute to range of problems like heart disease and depression. That was, indeed, what the philosopher Bertrand Russell argued back in the 1930s. Overwork, said Russell, led to "frayed nerves, weariness, and dyspepsia".

The pattern is not completely clear. The outlying figures to the right are those for South Korea. The country is famed for its long working hours, but also its healthy food, which may lower the risk of things like heart attacks and thereby reduce premature death rates. On the other side, Hungarians seem to get really stressed out at work: despite working relatively short hours, their PYLL is high.

If there is such a relationship between working hours and health, then shorter work hours might actually raise a person's total lifetime work by allowing them to live and work for longer. You can use that as an excuse next time you want to slack off early.