Application of the GPS technology to assess time-location pattern of undergraduate students at a private medical university in Karachi, Pakistan: A pilot study.

To compare time-location pattern of undergraduate university students through GPS and diary method, and with level of physical activity, a cross-sectional survey was conducted from September 2012 - May 2013 involving 50 undergraduate students from Aga Khan University. Data were recorded through GPS, diary method, International Physical Activity Questionnaire (IPAQ-L) and accelerometer (ActiGraph). Median self-reported time spent in the indoor-inside the campus, indoor-outside the campus and outdoor environment was 405 (IQR:300-540), 720 (IQR:465-840) and 300 minutes (IQR:180-495) respectively, while 52% of the students were in moderate, 40% vigorous and 8% in mild categories of physical activity. Mean differences in location (GPS versus diary method) were statistically insignificant; indoor residential, -30.2, indoor other, -26.2, outdoor at rest, 45.9 and outdoor travelling, 10.5 minutes. We conclude that students spent most of their time indoors-outside of campus and majority were physically active, while also demonstrating the applicability of GPS and ActiGraph for such studies.