This is the 4th post on the subject of "fatigue in the work place."

People get less sleep on the days they work than the days they are off. With each consecutive day of work, they fall farther and farther behind in their sleep, or what is commonly referred to as sleep debt. Sleep debt accumulates and is very subtle. People don't realize they are losing a small bit of cognitive ability every day their sleep debt builds up. With each passing night, they come to work less safe and less productive.

Reducing the number of consecutive days of work, gives employees time off to catch up on their sleep and pay off some of the sleep debt. While the number of days needed to fully recover is uncertain, most researchers believe that at least 2 days off in a row are needed to have a recuperative impact.

The problem with reducing the number of consecutive days of work, of course, is that the number of weekends off can drop dramatically, especially with 8-hour shifts. There is no easy solution to this. The schedules we design never exceed 7 consecutive 8-hour shifts or 4 consecutive 12-hour shifts. Only in special circumstances do we feel that these limits can be exceeded safely.