CIRCADIAN HEALTH

Modern lifestyles and work schedules – with late nights and irregular routines – can disrupt the body’s internal circadian clock. This circadian clock organises sleep patterns, affects cognitive performance, and influences our mental and cardiometabolic health. We are exploring the best ways to track, diagnose and manage circadian health.

Many real-world scenarios, including shiftwork and jetlag, create fundamental challenges for our circadian health, due to irregular patterns of sleep and light exposure. The timing and strength of our circadian rhythms is largely determined by light. Our research has revealed that individuals differ not only in the timing of their circadian clocks, but also how their clock responds to light. Therefore, circadian solutions need to be tailored to the individual.

OUR RESEARCH

Our research is investigating how circadian rhythms shape our overall health and implementing new solutions to mitigate circadian disruption.

We are studying light as a low-cost intervention to improve many aspects of health. We are developing new methods to track and predict circadian rhythms and implementing these tools into clinical practice.

Research projects

Wellcome Trust project investigating light to enhance antidepressant treatment efficacy
Wellcome Trust project investigating how light exposure patterns, and individual sensitivity to light, may predict Post-Traumatic Stress Disorder (PTSD)
ARC projects developing new tools to measure circadian light sensitivity, and evaluating the effects of our light exposure patterns on sleep
NHMRC project developing new methods to track and predict circadian timing from wearable data.
Understanding how light exposure patterns affect our physical and mental health
Understanding how light exposure effects cognitive performance and behaviour (e.g., alertness, gambling)
Investigating how circadian mechanisms contribute to sleep and Studying the impacts of circadian disruption in the context of shiftwork.

Featured publications

DP Windred, AC Burns, JM Lane, P Olivier, MK Rutter, R Saxena, AJK Phillips,. SW Cain (2024). Brighter nights and darker days predict higher mortality risk: A prospective analysis of personal light exposure in> 88,000 individuals. Proceedings of the National Academy of Sciences, 121(43), e2405924121.
DP Windred, AC Burns, JM Lane, R Saxena, MK Rutter, SW Cain, AJK Phillips (2024) Sleep regularity is a stronger predictor of mortality risk than sleep duration: A prospective cohort study. Sleep 47(1):zsad253.
AC Lander, MT Burge, BG Thomas, AJK Phillips, EM McGlashan, SW Cain (2025). Circadian photoreception influences loss aversion. Scientific Reports, 15(1), 13051.
Burge, M. T., Lumapas, R. A., Lander, A. C., Thomas, B. G., Phillips, A. J.K., & Cain, S. W. (2025). Blue light influences negative thoughts of self. Sleep, zsaf034.
A Guyett, N Lovato, J Manners, N Stuart, B Toson, B Lechat, L Lack, G Micic, S Banks, J Dorrian, E Kemps (2024) A circadian-informed lighting intervention accelerates circadian adjustment to a night work schedule in a submarine lighting environment. Sleep 47:zsae146.
DP Windred, AC Burns, MK Rutter, CH Yeung, JM Lane, Q Xiao, R Saxena, SW Cain, AJK Phillips (2024) Personal light exposure patterns and incidence of type 2 diabetes: analysis of 13 million hours of light sensor data and 670,000 person-years of prospective observation. The Lancet Regional Health–Europe 42:100943.
H Scott, B Lechat, A Guyett, AC Reynolds, N Lovato, G Naik, S Appleton, R Adams, P Escourrou, P Catcheside, DJ Eckert (2023) Sleep irregularity is associated with hypertension: findings from over 2 million nights with a large global population sample. Hypertension 80:1117-26.
PD Nguyen, C Dunbar, H Scott, B Lechat, J Manners, G Micic, N Lovato, AC Reynolds, L Lack, R Adams, DJ Eckert (2025) A novel method to separate circadian from non-circadian masking effects to enhance estimation of circadian timing and amplitude from core body temperature. Sleep Medicine 132:106530.
K Sansom, AC Reynolds, DP Windred, AJK Phillips, SS Dhaliwal, J Walsh, K Maddison, B Singh, P Eastwood, N McArdle (2024) The interrelationships between sleep regularity, obstructive sleep apnea, and hypertension in a middle-aged community population. Sleep 47(3):zsae001.
G Micic, N Lovato, SA Ferguson, HJ Burgess, L Lack (2021) Circadian tau differences and rhythm associations in delayed sleep–wake phase disorder and sighted non-24-hour sleep–wake rhythm disorder. Sleep 44:zsaa132.

Resources

Australasian Sleep Association

Sleep Regularity Index (SRI) R Package

WORK WITH US

We have long-term international and Australian sleep health partnerships across universities, South Australian Local Health Network and with industry groups. Please contact us to discuss opportunities.

Get involved