Projektdetails

Hintergrund
Demographic change is a challenging task for the social systems of the member states in the European Union (EU). The feared impact of demographic change could be mitigated by healthy ageing, as older adults in good health remain longer at work and can play an active role in society through volunteer activities (Sanderson and Scherbov, 2010). In humans, physical activity (PA) is essential for optimal functioning of skeletal, musculo- and digestive systems and also for circulation (Hallal et al., 2012). In this context, PA can increase life expectancy, daily living skills, and overall well-being and quality of life (Holme and Anderssen, 2015). An estimated amount of three million premature deaths can be attributed to a lack of PA, which could have been avoided through prevention and health promotion (Holme and Anderssen, 2011). In the28 member states of the European Union, the main causes of death are diseases of the cardiovascular system for which physical inactivity is one of the major risk factors (Holme and Anderssen, 2015; Kohl et al., 2012). In Europe, 35% of adults are considered as physically inactive and this proportion increases with age up to 45% in the 60+-year-olds (Hallal et al., 2012). We have recently shown that both moderate and high intensity exercise can lead to considerable improvements in physiological fitness and health related quality of life in previously sedentary older adults (Knowles et al. 2015).

The gold standard methods for measuring energy expenditure (EE) are indirect calorimetry and doubly labelled water, however, these are expensive and impractical and therefore of limited use in free-living population studies (Brochard et al., 1983; Spurr et al., 1988). Alternatively, accelerometery has been suggested as a cheaper and more practical method for estimating EE in larger epidemiological studies (Davidson et al., 1997). The tri-axial GT3x+ accelerometer (Actigraph, FL, USA) can be attached to either the wrist or the waist and detects accelerations and decelerations of the body in three different planes of motion 30 times every second and records this as accelerometer “counts per minute” (AC). Predefined algorithms can then be used to translate AC into EE and subsequently used to generate PA intensity thresholds (sedentary, light, moderate, vigorous). Laboratory based studies have found positive relationships between AC and EE (e.g. Crouter et al., 2006).

Despite this, there are no algorithms that allow PA intensity or EE to be estimated from an accelerometer placed on the wrist of older adults. Placing the accelerometer on the wrist is methodologically important as this location has been shown to increase compliance of wearing the device in comparison to the hip (Fairclough et al. 2016).
 

Projektziele
The primary aim of this research is to generate a novel algorithm that allows PA intensity and EE to be determined from an accelerometer worn on the wrist in older adults. The secondary aim is to validate the robustness of this algorithm during a series of laboratory and field based activities. The proposed study is a pilot study that will inform a larger scale validation study carried out as part of the OUTDOOR ACTIVE study with research collaborators in Scotland at the University of the West of Scotland (UWS) (http://www.aequipa.de/en/subprojects/outdoor-active.html)