Learn about the effects of shift work and circadian misalignment on health and how we tackle it.
See how research from our team is being used to deliver evidence-based support for shift workers and their organisations.
Scroll down for research on the SleepSync app.
What is Circadian Misalignment?
Circadian rhythms are natural, internal processes that regulate the sleep-wake cycle and repeat roughly every 24 hours. These rhythms are influenced by environmental cues, notably light and darkness, which help align our biological clock to the 24-hour day. They affect various physiological processes including hormone levels, body temperature, and sleep patterns.
Circadian misalignment in the context of shift work refers to the discord between an individual's internal biological clock, their sleep-wake and fasting-feeding patterns, due to non standard work hours. This can be particularly challenging and puts shift workers at a greater risk of cardiovascular disease, metabolic diseases and mental health conditions (figure).
Interventions such as strategic light exposure, careful timing of sleep schedules and meals can help manage and mitigate circadian misalignment in shift workers, potentially reducing associated health risks.
Figure reproduced from Sletten et al., 2020. More information available at: www.ncbi.nlm.nih.gov/pmc/articles/PMC7368337/
Our latest research
Unravelling the Impacts of Circadian Misalignment on Health.
Circadian rhythms, our internal body clock, regulate nearly every bodily function and are crucial for maintaining health. Disruptions to this system—often caused by shift work or presence of circadian rhythm disorders—can lead to a range of problems including poor sleep, depression, obesity, diabetes, heart disease, and even increased cancer risk. The letter highlights the importance of aligning our biological clock with natural environmental cues to improve health outcomes and calls for more clinical attention and research to manage circadian misalignment effectively.
Improving Night Shift Alertness with Blue-Enriched Light: An Operational Study
This study explored the use of blue-enriched light to help night shift workers at a chemical plant stay alert and perform better. By switching from regular to blue-tinted, brighter lights for four nights, workers showed noticeable improvements in alertness and were quicker on tasks compared to when under normal lights. We now know, through this research and several others how even simple changes in lighting can help those working at night feel more alert, enhancing safety and efficiency on the job.
Tailoring Sleep Schedules for Shift Workers Using Biomathematical Models.
This study explored whether it is feasible or practical to use biomathematical models, or biological models of sleep-wake to personalise sleep timing recommendations for shift workers. . Findings indicated an overlap of 73.62% between recommended and actual sleep times and significant improvements in sleep-related outcomes post-intervention, showing that shift workers can implement tailored recommendations for sleep and see improvements in their health and wellbeing.
Initial Efficacy of the SleepSync Mobile App
Shift workers used SleepSync for two weeks, and reported improvements in sleep quality, time, and ease of falling asleep. The app also positively impacted mood, reducing anxiety, stress, and insomnia symptoms. Feedback indicated high usability and integration into daily routines, underscoring the app's potential as a practical tool for improving sleep and mental health outcomes in shift work settings.
SleepSync Testing in Air Traffic Controllers
The SleepSync app was tested on 13 shift workers from the Royal Australian Air Force to evaluate its impact on sleep and cognitive fitness. Over four weeks of app use, the study found that average sleep duration increased by 30 minutes, and there was a clinically significant reduction in insomnia symptoms. Additionally, improvements were observed in sleep-related impairments and sleep practices. Cognitive fitness improved with a significant reduction in NBack incorrect responses, indicating better controlled response. While these findings are promising, the study highlighted the need for larger, randomized controlled trials to confirm the app's effectiveness across different settings and longer periods.
Using light interventions for shift workers
This editorial discusses the benefits of sleep- and circadian-informed lighting interventions for shift workers. Optimised lighting interventions, especially those incorporating blue light, help mitigate circadian misalignment by improving alertness and cognitive performance. Studies in controlled settings show promising results for circadian phase resetting and improved work performance. However, widespread adoption remains limited due to small sample sizes and a lack of industry-specific value assessments, highlighting the need for larger, personalised studies to encourage broader implementation.
