Shift Rotation

Rotation speed and direction. If shift rotation is unavoidable at the workplace, there are points that can be considered to reduce the impact of such rotations. According to the National Institute for Occupational Safety and Health (NIOSH) adapting to shift changes can be affected by the speed of the rotation and the direction of the rotation. The studies have mixed results regarding the speed of shift, but rapid changes (two days per shift) seem to be the most harmful. However, research clearly suggests it is better for a forward rotation (clockwise, or following the sun) of shift changes. This forward direction is healthier for allowing the body to adjust to new sleep times. Backward rotations force the body to adapt against the body rhythm by forcing sleep earlier and earlier.

Info source: http://www.massnurses.org/labor/education/2005/march/dangers.htm