Around-the-Clock Operations Lead to Health Problems

October 16, 2003 ( - That off-hours job might not be a pain in the neck, but could be one in the stomach, heart, lungs and marriage.

Employees regularly working evening and night shifts in around-the-clock operations suffer higher rates of gastrointestinal ailments, cardiovascular disease and sleep disorders than the general population. These ailments come in addition to higher consumption rates of cigarettes, caffeine and other stimulants than their daytime counterparts and much high instances of divorce and separation for parents working fixed-night shifts, according to a Circadian Technologies Inc. report.

Perhaps least surprising, given the hours do not correlate with the traditionally nine-to-five, extended hours workers also suffered sleep-related problems including chronic sleep deprivation, insomnia and sleep apnea (11% versus 2% to 4% for the general population). One particular danger is fatigue-related car accidents; 41% of extended hours employees reported nodding off while driving compared with 28% of day workers.

Late Work Load

As extended-hours employees now constitute more than 18% of the workforce in the United States, the health, and subsequently financial, impact on employers could be enormous. “Extended hours employees account for a disproportionate share of direct health care costs, and that number rises when indirect costs, such as absenteeism and turnover, are factored in,” said Acacia Aguirre, a doctor and Circadian medical director and principal author of Health in Extended Hours Operations: Understanding the Challenges, Implementing the Solutions. These costs run upwards of $28.1 billion annually in higher health insurance costs, amounting to $1,181 per extended hour employee, Aguirre says pointing to an earlier Circadian study.

Quantifying the numbers tied to the medical ailments, the report found peptic ulcers are two to five times more frequent among extended hours workers than among day workers. Using a standardized measure that rates digestive disorders, such as heartburn, nausea and abdominal pains, on a scale of 0 to 24, Circadian found that the average score for extended hour workers was 13 compared with a score of 8.5 for day workers.

Similarly, were the instances of cardiovascular disease based on epidemiological studies that showed an association between shift work and cardiovascular disease, including:

  • higher morbidity with increasing age and shift work experience
  • a higher prevalence of angina and hypertension
  • increased risk for mycocardial infarction in occupations with a high proportion of shift workers.

Suspected contributing factors include desynchronization of circadian rhythms tied to the cardiovascular system, such as blood pressure, lipids, cholesterol and insulin; changes in lifestyle affecting diet, smoking, alcohol and exercise; and increased stress over conflicts between work and family duties and activities.

Perhaps also adding to the deterioration of the overall health is a reliance on stimulants. Workers in extended hours operations are twice as likely to use prescription or non-prescription stimulants as the general population. Twelve percent of workers in extended hours operations reported using stimulants at least several times per month and 2% reported using them daily. This compares with a 2002 National Sleep Foundation (NSF) poll that found that 6% of respondents used stimulants. The highest use of stimulants in extended hours populations is among workers aged 25-34, who report the greatest alertness challenges while working.

Additionally, consumption of caffeinated beverages was also higher. Among all employees surveyed, average consumption of caffeinated beverages was two cups or cans per day. But extended hours workers drink on average more than three cups or cans per day. Among caffeine drinkers, 34.3% of night shift workers drank four or more cups or cans compared with 28% on the daytime shift.

The higher frequencies were also noted among the higher number of extend hours employees that are smokers. In fact, more than half (55%) of male extended hours workers smoke versus with a national average of 25% of men aged 18 or older and only slight fewer (51%) female extended hours workers smoke compared with 21% of women over age 18.

Cost Conscience

To alleviate some of the potential financial problems, Aguirre suggested adopting measures to mitigate these health problems. In fact, she noted that for every dollar invested in one measure, company-sponsored employee assistance programs, $16 is saved on average due to lower rates of accidents, turnover and absenteeism among employee populations participating in such programs. As examples of programs Aguirre suggests:

  • segregating and analyzing data according to shift schedule from health-care providers and payroll and personnel systems to determine which employee populations have the most critical needs for intervention programs.
  • optimizing shift duration, work recovery time (time off between shifts), overtime amounts and distribution patterns among employees
  • involving employees in schedule design and selection
  • selecting optimum shift start and end times for maximum sleep duration.

Study findings are based on data compiled from Circadian's annual survey of employees and managers and a comprehensive overview of studies of extended hours operations. It incorporates first-hand data collected from 10,500 extended hours employees in 60 companies and from managers at more than 600 companies or facilities representing approximately 120,000 employees across all major industry sectors.

An executive summary of Health in Extended Hours Operations: Understanding the Challenges, Implementing the Solutions can be obtained by contacting Tracy Maddaloni at (781) 676-6924 or