The British epidemiologist Jeremy N. Morris died recently. In the 1940s and 1950s, Morris did some of the first empirical research that showed how important it is, health-wise, to have a job that involves some physical activity. A 1949 study compared the health of the drivers of London's double-decker buses with that of the conductors."And there was a striking difference in the heart-attack rate. The drivers of these double-decker buses had substantially more, age for age, than the conductors." The data were so telling because drivers and conductors were men of much the same social class. There was only one obvious difference between them. "The drivers were prototypically sedentary," explains Morris, "and the conductors were unavoidably active. We spent many hours sitting on the buses watching the number of stairs they climbed." The conductors ascended and descended 500 to 750 steps per working day. And they were half as likely as the drivers to drop dead of a sudden heart attack.The idea that exercise is good doesn't seem particularly revolutionary today. But the thing is, this "information economy" hasn't been conducive to jobs that require you to break a sweat (or move at all, really, save your typing fingers). We seem to be moving towards more sedentary work. With unemployment at 10.2 percent, providing jobs of any stripe is tough right now, but we should also consider how to provide employment that doesn't leave people prone to heart attacks. And if we can do it without resorting to the treadmill desk, that'd be great.[youtube]http://www.youtube.com/watch?v=CPjN07JyVjoVia WSJ health blog. Photo from Flickr user Salim Virgi (cc).