Physical activity has been proposed as a novel way for shift workers to adapt to changing rosters and be more alert at work.

Strategic timing for exercise, light exposure, and sleep, may help with performance, mood and emotional regulation for shift workers, according to Central Queensland University (CQU) sleep research institute researchers.

Previous research has targeted lighting strategies alone to help workers adapt their circadian clocks to irregular work hours, said lead author and CQUniversity PhD candidate Dayna Easton.

“We typically assess an individual’s body clock by measuring biomarkers such as melatonin level and body temperature, which are influenced by external signals such as light exposure. For instance, light exposure during the early morning hours of a night shift will alter the body clock, meaning that workers will feel sleepy earlier in the night. 

“This obviously makes it more difficult to stay awake during the night shift. Ideally, what we need to do is alter the body clock in a different way so that workers feel alert during their night shifts, and sleepy afterwards.”

The CQU research argues controlling light is not always possible, for factors including safety and travel. 

“You can’t dim the lights in an emergency ward, or block morning sun coming into your car on the drive home,” said Ms Easton.  

Strategic physical activity could be a more accessible and cost-effective strategy to help adjust circadian rhythms and improve alertness at work and during a block of shifts, she said.

“Exercise can promote arousal, act as a time cue for the body clock, and become a habit that mitigates negative consequences of long-term shift work.”

Workers also needed support to understand their personal body clock patterns, she said. 

“Many of us know whether we are ‘early birds’ or ‘night owls’, but not how to take advantage of this. Understanding our own body clock patterns, and how they interact with our shift schedules will help decide what strategies work best, the timing of physical activity and also when to control for light exposure as much as possible.

“We know that shiftwork leads to impaired sleep, cognition, health and wellbeing, and an increased risk of occupational incidents – so countermeasures to improve sleep and alertness are vital.

Workplace support

The researchers recommend workplaces implement systems and practices to support fatigue and sleep.

“These strategies could look like providing napping or rest areas, healthy snacks, areas for physically active breaks, and also engaging with shift workers to understand which countermeasures they find most beneficial, said Ms Easton.

“Not only does this take the onus solely off workers but can hopefully help reduce barriers for countermeasure engagement and promote sustainable habit-forming.”

Read Move the night way: how can physical activity facilitate adaptation to shift work? is published in Nature Portfolio journal Communications Biology.

CQUniversity’s Appleton Institute, based in Adelaide, South Australia is a state-of-the-art sleep research leader in Australia and internationally, and conducts multidisciplinary research on health and wellbeing at work, rest and play.

Learn more at CQU’s Appleton Institute website.