Estimating Personal Physical Activity from Transport

A substantial and growing proportion of people in developed countries are overweight or obese. Personal physical activity protects against weight gain and obesity. Personal physical inactivity has been linked to a number of common and increasing prevalent health problems such as cardiovascular disease and a number of chronic diseases such as cancer (colon and breast), diabetes mellitus, osteoporosis and depression. Accelerometers can be used to objectively measure a person‟s incidental, intermittent physical activity such as short walks. They also enable movement to be monitored inside buildings that is often not recorded and is difficult using other technologies such as Global Position Systems (GPS). Accelerometers allow comprehensive analysis of physical activity bouts. They also have low subject burden, not having to rely on the memory of individuals and are unobtrusive, and allow recording over multiple days. However, accelerometers do not accurately record physical activity associated with cycling. GPS can be used to estimate personal energy expenditure from cycling since the speed and duration of movement is logged. However, GPS does not provide data at some locations such as inside buildings, urban canyons, or tunnels due to weak signals from satellites. Transport is a major activity type and common form of personal physical activity. This paper describes procedures for integrating GPS and accelerometers to estimate personal physical activity arising from transport. It provides experimental evidence using data from one subject and suggests that this method has potential for further investigation