It’s easy to underestimate the impact of a time change. After all, whether you’re springing forward or falling back, there is only an adjustment of one hour. Some say the responsibility of adjusting to the transition should fall to individuals, particularly when those individuals are expected to show up to work on time, fully awake and ready to get down to business. But some employers are paying attention to research indicating that changing the clock frequently increases worker fatigue and puts worker safety and health at risk. Unsurprisingly, many experts have cited more serious concerns following the switch to daylight saving time in March compared with the return to standard time in November, despite the impact both can have on humans’ circadian rhythms, physical and mental changes that follow a daily cycle.

“Losing one hour of sleep can be pretty significant,” says Lora Cavuoto, Ph.D., assistant professor of industrial and systems engineering at the University at Buffalo and of the ASSP Foundation-funded study “Advancing Safety Surveillance using Individualized Sensor Technology.” “But because it’s only one hour of less sleep, employers might not see some of the obvious, extreme signs of fatigue like eye closures or nodding off. There may be a reduction in work output or general presenteeism – people who are at work but not functioning at 100 percent.”

When a worker’s fatigue due to a lack of sleep crosses the line from slightly slowing their productivity to seriously impairing their judgment or physical control, it puts them and everyone around them in danger. So how can employers and employees remain vigilant and watch for the subtle warning signs? What are the best ways to manage fatigue risk? What’s the point of moving time forward, anyway?

Why Daylight Saving Time?

Daylight saving time (DST) has been observed in most of the U.S. for 100 years, off and on. It was adopted in 1918 during World War I to help conserve fuel, but was originally intended to be temporary and ended when the war was over. DST returned in 1942 during World War II for the same reason, but it wasn’t until 1966, when President Lyndon Johnson signed the Uniform Time Act, that the U.S. started officially observing it in regular intervals at a standardized time each year. Some areas, including Hawaii, Puerto Rico and most of Arizona, have opted out of DST. The Florida Senate voted to make DST a permanent state of affairs. According to the U.S. Department of Transportation, DST is intended to save energy, save lives, prevent traffic injuries and reduce crime.

Reduced Sleep, Reduced Safety

According to a 2009 study published in the Journal of Applied Psychology, employers in the mining industry have even seen a significant spike in the number and severity of workplace injuries on the Monday after the adjustment to DST over the years. Based on these findings and what numerous studies have shown about the importance of maintaining good sleep hygiene to perform tasks safely, it’s important to consider the effect disrupted or inadequate sleep can have across other industries. A “Fatigue Risk Management in the Workplace” guidance statement, which the American College of Occupational and Environmental Medicine (ACOEM) released in 2012, makes a convincing case for companies to implement fatigue risk management systems so they can identify and address sleep-related hazards, whether resulting from a time change or other factors. It starts by explaining why such systems are needed in the workplace.   

“Fatigue and decreased alertness resulting from insufficient or poor quality sleep can have several safety-related consequences,” ACOEM says, “including slowed reaction time, reduced vigilance, reduced decision-making ability, poor judgment, distraction during complex tasks and loss of awareness in critical situations.”

The statement describes sleep-related safety issues specific to shift work, where employees are often expected to work long and unpredictable hours in varying levels of daylight, preventing them from developing a sleep routine and making them more prone to sleep disruption. As such, it says many industries that have already adopted fatigue risk management systems employ shift workers, including transportation, mining, healthcare and pipeline. Cavuoto’s research echoes these findings.

“A few industries are taking a regulatory, policy-based approach to fatigue – transportation in particular,” she says. “Nursing and other healthcare groups are starting to address fatigue risk management, recognizing the issues related to shift length or time-on-task.”

Sleep-Related Worker Fatigue Costs Money

Estimates of the total yearly cost of lost productivity due to sleep-related worker fatigue vary, according to ACOEM, but its fatigue risk management statement cites two notable reports. The first, published in 1997 by the National Sleep Foundation, says that annual employer losses due to insufficient sleep in the U.S. approached $18 billion. The second, more recently published in 2010 and titled “The Cost of Poor Sleep: Workplace Productivity Loss and Associated Costs,” estimates a cost of $1,967 per employee per year in lost productivity due to sleep loss.

On top of the immediate costs resulting from the low productivity of sleep-impaired workers, employers could see the problem snowball, since sleep-related fatigue has also been frequently linked to health problems. Workers’ chronic health problems cost their employers significant sums of money. A National Center for Chronic Disease Prevention and Health Promotion fact sheet says chronically ill employees miss about 450 million more days of work each year than healthy employees, costing companies more than $153 billion annually. 

“Research increasingly demonstrates a positive association between short sleep duration and a variety of medical conditions,” ACOEM says, “including diabetes, hypertension, cardiovascular disease, adverse reproductive outcomes and obesity and its resultant medical issues.”

What Can Be Done?

No one believes that losing or gaining one hour of sleep due to a time change is going to upset employee circadian rhythms to the tune of $18 billion. However, when employers are sensitive to the sleep needs of their employees, and the ways that shifting clocks impede their safety and productivity, Cavuoto says everyone benefits. This could include implementing a more formal fatigue risk management system, like those described by ACOEM, but not necessarily. Some companies might benefit from a simpler approach, like slightly altering their hours of operation following a time change.

“I think an awareness of the potential issue is important,” she continues. “Companies should make sure not to put any critical activities on the day right after clocks change, when people might not be performing at their best. Realize that these are real effects and account for them when scheduling.”

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