This is the third in a series of posts regarding fatigue in the workplace. The first post addressed educating employees about the need for 8-hours sleep and the impact of sleep deprivation. The second post addressed early day shift start times and how they reduce the amount of sleep people get. This post will address the impact of shift length on sleep and fatigue.

Intuitively, you would think that the longer the work day, the less sleep you would get. To a certain extent, this is right. We have found that people working a 12-hour shift get about 10 minutes less sleep per night than people working an 8-hour shift. But that's not a complete picture since it is only looking at the days of work.

People on longer shifts get more days off. Workers on 12-hour shifts will get 87 more days off each year than those on 8-hour shifts. Since people sleep more on their days off than they do on the days of work, the people on 12s actually will average more sleep than those on the 8-hour work days. Here's a link to a table showing the details: http://www.shift-schedule-design.com/12-Hour_Shifts. You may have to scroll down a couple of times to find the table.

What do think? Counter-intuitive isn't it?