A recent study shows that exposing night shift workers to circadian-informed lighting may significantly improve their sleep quality and reduce human error on the job. A team of researchers led by Hannah Scott of Flinders University analyzed 19 adult workers who experienced either traditional dim lighting or circadian-informed lighting, which adjusted light exposure to support the body’s natural rhythms during night shifts. The findings revealed that the circadian-informed lighting significantly improved alertness, reduced sleepiness during shifts, and enabled participants to achieve longer, better-quality sleep.

The Challenge of Shift Work

In 2019, the U.S. Bureau of Labor Statistics reported that approximately 16% of wage and salary employees worked shift schedules. This includes 6% who worked evening shifts and 4% who worked night shifts. 

Shift workers often experience disruptions in their circadian rhythms, particularly those on night shifts. Circadian rhythms regulate our sleep-wake cycles and various bodily functions, aligning our internal clocks with the natural day-night cycle. Despite the challenges to the internal clock, shift work is essential in many industries, including healthcare and manufacturing. These irregular hours can disturb employees’ natural sleep-wake patterns, resulting in a range of negative effects, including:

• Sleep Disorders: Night shift workers frequently struggle with insomnia and other sleep-related issues due to misaligned circadian rhythms.
• Cognitive Decline: Fatigue can result in decreased attention, slower reaction times, and impaired decision-making. Previous studies have found that shift workers performed “significantly worse” in five categories of cognitive functions when compared to non-shift workers.
• Health Risks: Long-term shift work has been linked to chronic conditions, such as cardiovascular disease, diabetes, and mental health disorders.

Understanding how circadian rhythms operate is crucial for recognizing why shift work can be taxing. Nighttime exposure to bright, artificial lighting can confuse our internal clocks, making it challenging for workers to adjust to new schedules. This misalignment can lead to a cycle of sleep deprivation and cognitive decline, ultimately affecting job performance.

Exploring the Role of Circadian-Informed Lighting

The study involved 19 adults with an average age of 29. Conducted in a sleep health laboratory under controlled conditions that simulated night work environments, the participants experienced two different lighting conditions over an eight-day period. Circadian-informed lighting, combined blue-enriched lighting for alertness during simulated night shifts and blue-depleted lighting during day sleep periods. Researchers assessed several factors:

• Circadian Metrics: They measured melatonin levels, the sleep-regulating hormone, and core body temperature to assess how well participants adjusted to night shifts.
• Cognitive Performance: Participants completed various tasks that measured response times and attention lapses.
• Sleep Quality: Sleep studies tracked the duration and quality of daytime sleep. Participants were also asked to self-rate their current level of sleepiness.

The Science Behind the Findings

Circadian-informed lighting mimics natural light patterns, utilizing blue-enriched light to promote alertness and enhance mood. This approach helps synchronize the body’s internal clock with the external environment, optimizing cognitive performance during working hours. The study’s results align with previous research indicating that light exposure can significantly influence vigilance and sleepiness, particularly during nighttime work.

“The overarching benefits of circadian-informed lighting on sleep and alertness are very clear from this study. Our findings suggest that strategic lighting interventions can likely be used to enhance the performance, sleep, safety, and well-being of night shift workers exposed to inadequate light during their work shift,” says study co-author Alisha Guyett. “The circadian-informed lighting interventions significantly accelerated participants’ adjustment to night work, which could have important implications for improving the health and performance of those who regularly work night shifts.”

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