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Exploring the interplay and mechanisms between sleep, circadian rhythms and physical activity in relation to physical and mental health

   MRC GW4 BioMed Doctoral Training Partnership

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  Dr Rebecca Richmond  No more applications being accepted  Funded PhD Project (Students Worldwide)

About the Project

Understanding the interplay between physical activity and sleep is important for improving physical and mental health. A proposed mechanism linking physical activity with improved sleep is through regulation of circadian (24-hour) rhythms in the body. This project will investigate the relationship between physical activity and sleep, and the underlying biological pathways, using both population and experimental research methods. 


As part of this interdisciplinary PhD, the student will investigate the inter-relationships between physical activity and circadian/sleep measures in order to better understand how they interact to influence physical and mental health. This will be done using both epidemiological (observational and genetic) and experimental (in-vivo and ex-vivo biology) approaches.

For the epidemiological aspects of the study, data from two European biobanks (UK Biobank, n~500,000 and the HUNT study, n~125,000) will be used. These studies have obtained self-reported and objective measures of physical activity and sleep, the latter being derived from accelerometers worn by ~90,000 participants in UK Biobank and ~30,000 participants in HUNT. Variables to be assessed will include: intensity, duration, type and timing of physical activity; measures of sleep timing, sleep duration and insomnia; as well as measures of mental and physical health from direct assessment and electronic health records. Analysis of UK Biobank data will be supported by Drs Richmond (University of Bristol) and Tyrrell (University of Exeter) and analysis of HUNT data will be supported by Dr Skarpsno (NTNU, Norway).

Recent genome-wide association studies have identified genetic variants robustly associated with both self-reported and device-measured physical activity [4-6] and sleep [7-9]. These variants can be used in a Mendelian randomization (MR) approach to establish directionality between the physical activity and sleep measures and to estimate causal effects. By being positioned within the MRC Integrative Epidemiology Unit in the Bristol Medical School and affiliated with both the University of Exeter and NTNU, the student will draw on a wide range or resources and expertise for developing their knowledge and skills in the application of MR approaches.

For the experimental study, Prof Piggins’ lab within the School of Physiology, Pharmacology and Neuroscience at the University of Bristol have existing data on scheduled exercise and feeding/drinking rhythms in normal and mutant mice which could be used to develop a model of interactions between these. Another data set has monitored body weight among mice exposed to different light-dark and schedule exercise conditions. Finally, ex-vivo work can be carried out to investigate molecular pathways underlying the effects of scheduled voluntary exercise on circadian regulation by investigating gene expression in different brain structures and tissues in mouse models. Lab findings will be followed up in the human epidemiological studies and triangulated to better establish the interplay and mechanisms between sleep, circadian rhythms and physical activity.

The student will develop ownership of the project by deciding on the optimal split between wet and dry lab research approaches as well as the specific data sets and research questions. Further, the student will decide upon the context in which to evaluate the interplay between sleep and physical activity traits, in terms of the physical and/or mental health trait(s) to be investigated.

Lead Supervisor: Dr Rebecca Richmond, Population Health Sciences, Bristol Medical School, Faculty of Health Sciences

Co-supervisors: Professor Hugh Piggins, Dr Jess Tyrrell, Dr Eiving Schjelderup Skarpsno

How to apply 

This project is part of the GW4 BioMed2 MRC DTP projects.

Please complete an application to the GW4 BioMed2 MRC DTP for an ‘offer of funding’. If successful, you will also need to make an application for an 'offer to study' to your chosen institution. 

Please complete the online application form linked from our website by 5.00pm on Wednesday, 1st November 2023. If you are shortlisted for interview, you will be notified from Tuesday 19th December 2023. Interviews will be held virtually on 24th and 25th January 2024. Studentships will start on 1st October 2024. 


For enquiries regarding the application procedures please contact [Email Address Removed]  

For project enquiries contact Rebecca Richmond [Email Address Removed]

Biological Sciences (4) Medicine (26) Nursing & Health (27)

Funding Notes

This studentship is funded through GW4BioMed2 MRC Doctoral Training Partnership. It consists of UK and international tuition fees, as well as a Doctoral Stipend matching UK Research Council National Minimum (£18,622 p.a. for 2023/24, updated each year).

Additional research training and support funding of up to £5,000 per annum is also available.