The research activities of the Chronobiology team involves the study of human circadian rhythms, ranging from molecular function to physiology.

Professor Debra Skene and her team's research is focussed on the human circadian timing system in particular investigation of the causes, consequences and treatment of circadian rhythm disorders. Optimisation of therapies to correct human clock disorders, such as appropriately timed light and melatonin, is a long term goal.

Current research projects

• Role of eyes and visual pathology on the human circadian system
• Circadian photoreception
• Ageing and the circadian system
• Cardiovascular function and the circadian system
• Adaptation to shift work
• Does a change in main meal time shift biological rhythms?

Role of eyes and visual pathology on the human circadian system

Circadian rhythms in physiology (cortisol, melatonin, temperature) and behaviour (sleep/wake, alertness, performance) are being characterised in individuals with a range of visual pathologies. Their response to light (light-induced melatonin suppression) is also being investigated. The effect of visual disease on the circadian system and sleep/wake patterns is being studied with a view to optimising treatment of this condition (e.g with melatonin administration).

Circadian photoreception

Work from our laboratory has shown that short wavelength blue light is the most effective at suppression of nocturnal melatonin and phase shifting the circadian clock in humans. Studies designed to investigate the spectral sensitivity of non-visual light responses are ongoing in order to determine the contribution of rods/cones and/or novel photoreceptors in photic entrainment. The effect of ageing on non-visual light responses is also being studied.

Ageing and the circadian system

A consortium of 4 European partners was awarded a EU FP6 Marie Curie Research Training Network grant (4.5 million euros, 2005-2009) to allow early and experienced researchers to work in the network specifically addressing sleep problems and the effects of sleep restriction. Marie Curie Fellows in Chronobiology are Dr Tracey Sletten, Ms Katharina Lederle, Ms Sophie Wehrens and Dr Katrin Ackermann.

The ability of light to improve sleep, mood and alertness in the elderly is currently being studied both in the community and in care homes with funding obtained from Cross-Council New Dynamics of Ageing (NDA) Initiative, a multidisciplinary research programme supported by AHRC, BBSRC, EPSRC, ESRC and MRC, SomnIA and Philips Lighting.

Cardiovascular function and the circadian system

We have shown that endothelial function varies with time of day and is affected by age. Currently we are looking at the effect of sleep deprivation on endothelial function and markers of cardiovascular risk in controls and shift workers.

Adaptation to shift work

The effect of different shift work schedules, season, inter-individual differences and age on adaptation to shift work is being studied both in simulated and field studies. Treatments designed to hasten adaptation (e.g. appropriately timed light exposure) are being explored.