Many scientists have documented the benefits of bright light exposure on shiftworkers. Laboratory research suggests that three periods of 3 hours of 2500 Lux (tripling the approximate 500 Lux found in a brightly lit office at night) can induce a 7 hour delay of biological clock or circadian rhythms (Bougrine et.al. 1993). In other words, the extra wattage improves sleep, mental performance and subjective alertness, resulting in better adaptation to changing work schedule. A pilot study conducted at the Universite Rene Descartes in Paris, France tested the impact of increased light on 14 operators on a derrick-laying barge in the typically overcast North Seas. During fixed 12 - hour shifts, the subjects were exposed to bright light (2500 Lux) for three hours during three consecutive days at 0200-0500, 0400 - 0700 and 0600 - 0900 for subjects on the shift 2400 - 1200 and at 0800 -1100, for subjects on shift 1200 - 2400. For each shift, a control group was established who were not exposed to bright lights. Comparisons between the two groups were made in fatigue and temperament. The pilot study found that bright light significantly improved sleep duration and quality. In fact, sleep periods increased from 50 - 95 minutes. Also notable was a decrease in fatigue and irritability during the light-enhanced work period. The control group, not exposed to bright lights, demonstrated increased tiredness and moodiness.

By sheer numbers, shiftworkers are becoming the backbone of the country. According to a U.S. Dept of Labor Report of May, 1991, shiftworkers comprise 18 percent of the total full time workforce. Among part time, temporary and flextime employees, one-forth or working men and 16 percent of working women are shiftworkers.

Since emergencies never sleep, 64 percent of protective service workerscover other-than-day shifts. Twenty-six percent of operators, fabricators and laborers are shiftworkers. Among industries, the highest incidence of shiftwork occurs in primary metals, textile mill production, paper production, rubber and plastics manufacturing. At least 30 percent of employees in transportation, eating and drinking establishments, entertainment and recreation do shiftwork.

Presently, the lowest percent of shiftwork is found among executives, administrators and managers. The future though, according to Jack Greenshields, senior vice president for Waldorf Corporation, will change. He said, "As shiftwork increases... we will experience a major paradigm shift as managers, and executives will no longer work just straight days."

The day shift in the plastics plant had the highest work volume and the highest overall injury rate.  In the crowded working environment of the plastics plant the most common injuries reported were categorized as physical-impact such as "slipped or tripped' or "hit by equipment." Workers on the evening and night shifts attributed "used tools incorrectly  as the cause of injury more frequently than day-shifters.  This finding aligns with the finding that maintenance work was primarily conducted on the later shifts.  Self-reports from the plastic plant included reports of "breathing fumes" which resulted in "breathing problems."

Data collected from the glass plant (rotating shifts) revealed no shift difference in specific injuries or event with the exception "broken bones" which was found to be most common on the day shift.  Self-reports from the glass plant provided enough data to suggest that the day shift experienced the greatest number of injury events and resulting injuries.

In the plastics plant (permanent shifts), differences in both the amounts and the types of injury events and resulting injuries suggest that safety interventions should be adapted to the unique differences that accompany different shifts.  In the glass plant with rotating shifts, the shifts varied in the amounts, not the types of events and injuries.  This was not unexpected, given the constancy of the workers and the production process across the rotating shifts. Clearly, a safety interventions should focus special attention on the the shift and workload issues.
(Research report from Carlla S. Smith, Ph.D et.al. Bowl;in Green University. International Journal of Occupational and Environmental health. P S46-S52.)

Shiftworkers, more than other employees, tend to stick together.  This phenomena is noted by Kent Boll, supervisor aircraft maintenance, Northwest Airlines who says, "The employees tend to be a tighter bunch, both personally and professionally with very close, long-standing relationships. The 3rd shift seems to be more sensitive to personal stimuli than other shifts."

In that same article, Bill Otto,  Chief on 3rd shift says, "The crews are very tight with one another, supporting each other."

The camaraderie of shiftworkers who work and socialize together helps them view their lifestyles as "normal."  Such cohesive groups will often out-produce other shifts and have lower rates of absenteeism.  That positive result, though, can sometimes become a negative if the shift begins to slip into "group think."

According to Rollin Glaser, Ed.D author of Group Think Index, "Group Think" happens when there is a high degree of group cohesiveness.  Workers begin to agree in order to maintain the group's sense of solidarity.

Irving Janis (1983) has identified symptoms of group think.  The easiest symptom to spot is when one or two persons prevent others from sharing opposite points of view.   These self-appointed leaders may apply direct pressure to anyone who disagrees with the majority opinion. 

Healthy ties among members of the night shift makes them feel valued as individuals and as co-workers.  Group think, though, discourages any opposing point of view.   Janis suggests that group think can be overcome by encouraging critical thinking, checking assumptions, and refraining from stating expectations at the onset. Another helpful bit of advise is for managers to be sure there is enough supervision on all shifts providing for good communication and feed back on all issues.  If this piece of the puzzle is missing, there is fertile ground for "Group Think" to get established.

Shiftwork is rarely easy.  But workers' home life and social life are affected differently depending on whether they work 8 or 12-hour shifts, according to one recent study.

The subjects were 61 women who work 12-hour shifts (work one day, then one night, then take two days off); 78 men who work that same pattern of 12-hour shifts; and 69 men who rotate their 8 hour shifts (two days each of morning, afternoon and night.) Questions covered the particular shift system worked, individual differences such as gender and age, and ability to tolerate shiftwork.

Workers' tolerance for shiftwork and their mental attitudes about it did not differ significantly among the various shifts.  However, domestic life and social life were most disrupted for those workers on 8-hour shifts. Regardless of gender, workers in 12-hour shifts reported less disruption of their personal life than did workers in 8-hour shift systems.

In a study conducted in 1996, researchers focused on two major questions regarding job performance and well-being of shiftworkers:   Do the number of rest days between work spans affect performance and well-being on subsequent work days?  And, do the number of consecutive shifts have an effect on performance and well-being?  Sixty-one nurses participated in the study.  Half of them worked full-time shifts that rotated among early, late, and night shifts; the remaining were full-time or part-time shiftworkers.  The researchers found that as rest day increased, so did sleep length, quality of sleep, alertness, calmness, cheerfulness, mood symptoms and social satisfaction.  A recovery factor from shiftworkers was noted by the second and third day off, an indication that readjustment from shifts occurs over time.  Consecutive days of rest were found to be beneficial.   The study also revealed that too much rest time may cause difficulty in adjusting to a night routine.

Well rested nurses returning to a day or night shift reported social satisfaction.   On the other hand, those returning to a night shift after more than 2 rest days experienced difficulty in acclimating themselves.

Based on their findings, the researchers suggest the following:

1)  Since well-being was recorded as lowest on the first rest day with a steady improvement on following days, scheduling 2 consecutive rest days is optimum.

2)  Increase the number of consecutive shifts to compensate for increased rest days. This recommendation is based on 3.29 being the average number of consecutive shifts and few changes occurring across all shifts.

3)  Do not consider the day on which the night shift ends as a rest day since alternating between a night and day routine created difficulties such as decrease in both sleep duration and alertness

Increasing scientific evidence supports a linkage between shiftwork and depression.  A follow-up survey of 15 cases of depression revealed that depression among shiftworkers was higher than that of the general population.  The survey investigated three categories: 1) depression directly related to shiftwork; 2) reactive depression, probably exacerbated by shiftwork; and 3) reactive depression linked to a major life event.

Those surveyed were asked: "All other things being equal, would you have preferred to give up working shifts and get a day time job?" Three out of seven whose depression was connected to a major life event responded, "definitely yes."  One out of four whose depression was intensified by shiftwork answered similarly. Three of four whose depression was directly associated with shiftworker also said, "definitely yes."

In summary, depression, among shiftworkers for the most part occurred during   shiftwork.  Eighty-six percent of category three cases happened after stopping shiftwork.  Evidence of marital conflict related to the shiftworker's schedule accompanied category one depression. Those in this category also reported a significant disruption in social and/or domestic life.

Beginning between the ages of 40 to 50, circadian rhythms begin to vacillate.  Circadian rhythms are naturally occurring body rhythms; i.e., cell division, blood pressure and hormone release.  One result is "occupation jet lag" or an inability to stay alert during a shift.  One shiftworker described occupation jet lag as: "The body is there, but the mind is gone."

Sleep patterns change as one gets older.  The main effects include:

A general decrease in the slow-wave activity which determines if the sleeper feels physically rested upon waking.

More awakenings.

Longer stages of light sleep.

Those experiencing and noticing physical and emotional changes need to share their feelings and thoughts with their partner, spouse or friend.  To begin the discussion, let them read this article. The shiftwork lifestyle can be a "shared journey" if friends and family understand the changes that accompany getting older.