The negative impacts on human health and performance from 24-hour work shifts are generally well known. A March 2011 discussion paper titled The Health and Safety Impacts of 24 Hour Shifts in Fire Departments by the Ontario Association of Fire Chiefs and Ontario Municipal Human Resources Association reported the following among the published conclusions:
“This paper reviewed more than 60 published research studies which focused solely on the health and safety impacts of extended work shifts on employees. Most of these are peer-reviewed studies published in scientific journals. The reviewed studies were consistent in their conclusions that night shifts and extended shifts (those over 16 hours) present safety and health risks for workers. Combining long shifts with night time work compounds the risks. The studies found that the rate of accidents and injuries increase with hours on the job. After 16 hours on the job, fatigue has a major impact. If work tasks require alertness, sleeping on the job may present a safety risk due to sleep inertia or “grogginess‟ upon waking. Shift workers working extended shifts face an increased risk of sleep disorders, gastrointestinal disorders, diabetes, cancers and heart disease.”
Samuel Blackstone’s essay titled Pulling an All-Nighter Is Worse Than Six Months of Unhealthy Eating, reports that researchers at Cedars-Sinai Medical Center in Los Angeles, CA had determined that working a 24-hour shift is seriously detrimental to one’s health. The study suggests that one night of total sleep deprivation may be as detrimental to insulin sensitivity as six months on a high-fat diet. This research demonstrates the importance of adequate sleep in maintaining blood sugar levels and reducing risk for metabolic diseases like obesity and diabetes.
Health Effects of Shift Work (2010)
A 2010 scientific symposium on the health effects of shift work found that shift work is widespread with more than 20% of the workforce in North America and Europe engaged in shift work, requiring working at night or non-traditional hours. Shift work can result in sleep disruption and sleep deprivation and in sleepiness/fatigue at work. Night shift work has been associated with an increase in breast cancer in women who work rotating shifts for longer durations (i.e. 30-plus years). Evidence from animal studies supports the link between circadian disruption (in the form of suppressed melatonin production) and the growth of tumors.
In 2007, based on limited evidence from human studies and sufficient evidence from animal experiments, the International Agency for Research on Cancer (IARC) classified “shift work that involves circadian disruption” (i.e. night shift work) as a probable human carcinogen (Group 2A). There is strong evidence that night, evening, rotating and irregular shifts are associated with an elevated risk of workplace injuries. There is evidence that shift work has a moderate negative effect on fetal growth in pregnant women.
According to the Cleveland Clinic, Shift Work Sleep Disorder (SWSD) is a dysfunctional condition that affects people who frequently rotate shifts or work at night. Schedules of these people go against the body's natural circadian rhythm, and individuals have difficulty adjusting to the different sleep and wake schedule. SWSD consists of a constant or recurrent pattern of sleep interruption that results in difficulty sleeping or excessive sleepiness. This disorder is common in people who work non-traditional hours, usually between 10:00 p.m. and 6:00 a.m. The most common symptoms of SWSD are difficulty sleeping and excessive sleepiness. Other symptoms associated with SWSD can include difficulty concentrating, headaches or lack of energy.
Consequences of SWSD include:
- Increased accidents
- Increased work-related errors
- Increased sick leave
- Increased irritability or mood problems
These findings suggest that individuals with SWSD are at risk for significant behavioral and health-related morbidity associated with their sleep-wake symptomatology. Further, it suggests that the prevalence of SWSD is approximately 10% of the night and rotating shift work population.
One additional study found those individuals with either insomnia or excessive sleepiness and who were currently working rotating or night schedules and classified as having shift work sleep disorder suffered a number of specific negative consequences including: significantly, higher rates of ulcers, sleepiness-related accidents, absenteeism, and depression more frequently compared to those shift workers who did not meet criteria. Importantly, in most cases, the morbidity associated with SWSD was significantly greater than that experienced by day workers with identical symptoms.
24-hour stints (even if infrequently experienced) and routine night shift work schedules are common in the emergency operations, contingency management, and crisis disciplines. These non-traditional work schedules can negatively affect individual health and job performance, in some instances perhaps significantly.
Adjustments to regular work schedules, adequate rest periods, cessation of variable work schedules and additional physical and psychological support may be necessary to ensure the readiness of our workers during non-traditional periods.
Specific corrective steps may include: decreasing the number of night shifts worked consecutively, avoid extended work hours beyond the normal end of shift timeline, avoid or minimize long commutes, avoid rotating shifts, facilitate good worker sleep and rest patterns to ensure adequate rest, and institute appropriate rest and break patterns during the work shift; and adjust environmental conditions (e.g. lighting, climate, ergonomic work stations, etc.) to minimize fatigue during work shifts.
Images: culturecountermag.com and Firestorm, respectively