ASCI 638, Assignment 5.5, Shift Work Schedule

Rotating shift work is necessary for missions requiring 24-hour, seven days a week, 365 days a year (24/7/365) operations.  The physiology of human beings can make these types of operations difficult to support due to the toll on the human mind and body.  Optimizing the length of duty shifts and ensuring employees get sufficient time to rest and recuperate can mitigate these negative effects on the mind, body, and performance.

According to the University of California, Los Angeles (UCLA) Sleep Disorders Center (2006), rotating shift work can negatively affect one’s physical health.  Difficulties in getting sufficient rest and sleep can lead to degraded immune systems and increased probability of illness.  Lack of recuperation time can also cause decreased alertness levels and increased probability of workplace injury.  Mental health can also be negatively affected with a shift worker suffering from bad or depressed moods.  These emotions are caused by the shift worker feeling disconnected from family, friends, and a society geared toward traditional daytime-shift workers.  Burgess (2007) writes that physiological variations in a human being’s natural 24 hour pattern are termed circadian rhythms.  A person shifting their wake-sleep pattern out of phase disrupts this relatively stable rhythm.  Night shift workers sleep 25 to 33% percent less than day or swing shift workers and can lose one to three hours of sleep per night for the first three days after changing to night shift.  Some of the incidents attributed to fatigue-induced human error include: The Chernobyl nuclear plant, Space Shuttle Challenger, Bhopal Union Carbide tragedy, and Exxon Valdez oil tanker spill (Burgess, 2007).

Operating aircraft, such as unmanned aerial systems (UAS), can also be significantly affected by operators afflicted with the fatigue and stress induced by rotating shift work.  The problems can be mitigated by decreasing the number of working hours in a given period and providing sufficient rest and recuperation time between work periods to transition shifts.  In the assignment’s example scenario, the U.S. Air Force MQ-1B Predator unit is organized into four teams working eight hour shifts to provide 24/7/365 operations.  The schedule calls for each team to work six consecutive shifts, two days off duty, and then rotation to another shift.  In a given 14 day period, a team member will work 96 hours with only two days off before rotating shifts.  Burgess (2007) writes that at least three days are needed to recover from changes in the sleep-wake cycle.  Optimal scheduling would also limit shifts to eight hour durations and to three consecutive night shifts.  However, additional teams (Above the four teams specified in the scenario) would be required to meet these goals.  Assuming that the scenario is limited to the four teams specified, an alternative schedule is to change the shift duration to 12 hours.  Each team will work a two on, two off, three on, two off, two on, then three off before rotating shifts.  Although this will not meet the optimal eight hour shift duration, this will limit consecutive night shifts to three and allows for three days off before rotating shifts.  Over a given 14 day period, each team member will work 84 hours with seven days off.

           Although rotating shift work is not natural to most people and can take a psychological and physical toll on one’s body, it is necessary for certain types of operations.  Careful scheduling can mitigate some of the negative effects of disruption of the human body’s natural, circadian rhythm.  An important aspect that must be considered when developing a 24/7/365 shift work schedule is to consider the morale and feedback from those who will be working such a schedule.  The knowledge and confidence that leadership is receptive to and cares for the well-being of subordinates is an important morale factor that goes beyond the schedule.


References:

Burgess, P.  (2007, April).  Optimal Shift Duration and Sequence: Recommended Approach for

Short-Term Emergency Response Activations for Public Health and Emergency Management.  American Journal of Public Health, 97(Supplement 1), p. 88-92.  Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1854972/

University of California, Los Angeles Sleep Disorders Center.  (2006).  Coping With Shift Work

[Fact Sheet].  Retrieved from http://sleepcenter.ucla.edu/coping-with-shift-work