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Reference : UMR7178-FLODIE-001
Workplace : STRASBOURG
Date of publication : Thursday, August 01, 2019
Scientific Responsible name : BERGOUIGNAN Audrey
Type of Contract : PhD Student contract / Thesis offer
Contract Period : 36 months
Start date of the thesis : 1 October 2019
Proportion of work : Full time
Remuneration : 2 135,00 € gross monthly
Description of the thesis topic
Description of the Thesis Project
Objectives of the thesis
- To understand long-term effects of fragmenting sitting time with short active bouts on physical activity pattern and energy metabolism;
- To understand long-term effects of fragmenting sitting time on metabolic profiles and metabolic flexibility;
- To understand long-term effects of fragmenting sitting time on eating behaviours and general well-being;
- To compare these effects with those induced by the practice of physical activity as a continuous sinble bout of activity, matched for total active time and energy expenditure;
- To learn the following techniques: three-dimensional accelerometry, indirect calorimetry, doubly marked water method, nutrient fate tracing technique, continuous interstitial glucose monitoring, use of questionnaires and visual analogue scales to detect changes in eating behaviour and well-being;
- To learn to disseminate research data at conferences and through the publication of scientific articles in peer-reviewed journals.
- To defend PhD Thesis in a period of 3 years;
Scientific field and themes
Metabolic health, sedentary behaviors, physical activity, metabolism
There are obvious reasons to promote sport and exercise for health. However, recent epidemiological studies indicate that even among people who exercise regularly, a reduction in sitting time can provide major health benefits. These studies also highlighted the importance of intermittent periods of physical activity (PA). Adults with uninterrupted sedentary periods have less healthy metabolic profiles than those who frequently interrupt sedentary time, regardless of age, sex and total sedentary and active time. However, there is little understanding of the underlying mechanisms. In the absence of such data, public health guidelines to prevent the impact of physical inactivity on health will remain non-specific. Our group is working to (i) understand the role of sedentary behaviours in the emergence of chronic diseases, (ii) develop new PA protocols to prevent sedentariness and its harms.
Our preliminary and published data suggest that frequent interruptions in sitting position due to short episodes of PA provide short-term benefits in carbohydrate metabolism, insulin sensitivity and metabolic flexibility, a key component of metabolic health that corresponds to the ability to use fasting fat but carbohydrates in postprandial conditions to provide energy to the body. An improvement in satiety, well-being was also observed. Unexpectedly, these effects are more pronounced than those induced by a continuous episode of aerobic PA, which is equivalent in terms of duration and energy expenditure. However, the long-term effects of an increase in PA through the fragmentation of sedentary time and the ability of individuals to adopt this strategy on a daily basis remain unknown.
This thesis project will seek to answer these questions. He/she will compare the effects of frequent interruptions of sedentary time with traditional training, equivalent in terms of duration and energy expenditure, on (i) AP profiles and energy metabolism by combining the use of 3D accelerometers, indirect calorimetry and the doubly labelled water method, (ii) biomarker profiles of metabolic health, (iii) the use of lipids and carbohydrates measured using tracing techniques, (iv) daily blood glucose levels, and (v) feeding behaviour and well-being.
Collaborative aspects/partnerships envisaged
The project will be placed within the framework of the Joint International Laboratory (LIA - ACTIMOVE) with the University of Colorado in the United States (Drs. Daniel H. Bessesen, Edward L. Melanson, Paul S. MacLean). Nationally, it will be conducted in collaboration with Prof. Chantal Simon (PU-PH) of the Rhône Alpes Human Nutrition Research Centre.
The Institut Pluridisciplinaire Hubert Curien of the National Centre for Scientific Research (CNRS) is an institute composed of three departments, one of biology, one of chemistry and one of physics. The institute is located in Strasbourg, France. The Department of Ecology, Physiology and Ethology is interested in understanding the physiological and behavioural adaptations of animals, including humans, to environmental changes. The "Physiological Adaptations to Gravity & Health" team led by Dr. Audrey Bergouignan is conducting an interdisciplinary research program to understand the respective contribution of ecological, biological, sociocultural and anthropological factors in regulating energy balance, weight and metabolic health. The team has the equipment, expertise, experience and funding to conduct this project.
- Master's degree or equivalent in nutrition, exercise physiology, physiology, ecophysiology, physiopathology;
- Research internships;
- Good level in English;
- Excellent writing and oral presentation skills;
- Other: Synthesis and critical thinking skills; Flexibility and adaptability; Teamwork skills while being autonomous; Curious and enthusiastic; Creativity; Initiative; Resilience.
Documents to provide
Letter of motivation
At least two references (people who can be contacted)
Constraints and risks
The thesis will be attached to the ED414 Doctoral School of Life Sciences at the University of Strasbourg. The graduate student will participate in the courses and training required by the doctoral school. He/she will also be expected to participate regularly in DEPE, team and other meetings related to his/her work. He/she will also be required to present his/her research work at the Department's monthly seminar.
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