Energy Profile and Low Intensity Activity (PROFILE)

Overview

The recent literature has highlighting the importance of the time of SB and the level of physical activity (PA) as predictors of metabolic cardio risks. Now, sedentary lifestyles are well recognized as one of the causes of mortality. As with physical activity, a dose-response relationship appears to exist: mortality would increase with time spent in sedentary behaviors. However, this relationship would not be linear: the more the daily sitting time increases, the more the consequences on mortality are important. It is now well demonstrated that time spent in sedentary adult behaviour finds primarily its origin in the work, characterized by prolonged and uninterrupted periods of sitting. Many strategies have been settled to break the prolonged sitting time. The most promising one seem to be the use of active workstations (standing, walking, cycling, stepping) because they reduce sedentary time at work and increase physical activity with positive effects on the global health. However inter variability in energy response have been identified during a sit to stand allocation with subject "savers" profile showing an increase in energy expenditure while others categorized as "non-savers" increased significantly their energy expenditure between sitting and standing position. As others active workstation strategies exist, this study aim to first, better characterize energy response to posture and activity allocation (15min sit-15min stand-15min sit-15min low intensity cycling), secondly to identify parameters that could explain different energy profile.

Subject will have an inclusion visit during a medical consultation where the eligibility criteria to participate to this study will be checked. During a second experimental visit, subjects will have to take a calibrated breakfast. Three hours after the breakfast, body composition will be assessed and energy expenditure and substrates oxidation will be measured with an indirect calorimetry device during 15min in a sitting position fallowed by 15min in standing position , 15min in a sitting position and 15min of low intensity cycling with a cycling desk. Then subjects will underwent physical capacity test : * 6min step test * Handgrip test * lower limb strength test Finally, subjects will be equipped with accelerometer and inclinometer device they will need to wore during 7 days.