Background: The World Health Organization (WHO) reported that the proportion of senior citizens (over 60 years old) in the world population will reach 30% by 2050. Governments with rapidly ageing societies, such as Japan, urge local communities to develop sustainable solutions that facilitate healthy ageing. A vital component of the solution is for individuals to self-monitor their daily activities and health statuses. With advances in wearable devices, the self-monitoring practice of lifelogging, has become accessible for many people, making such devices promising tools for senior citizens. However, the current understanding of the effective practices of supporting senior citizens through lifelogging technologies is still limited. Methods: This article reports the findings of a study that investigated the feasibility and effectiveness of a lightweight GPS-based lifelogging approach exercised by senior citizens in Japan. We asked ten participants to carry a smartphone when they went out, and the device automatically captured their activity and location data. We also generated monthly personalised reports to help participants reflect on their daily lives. We analysed the log data collected by the mobile devices, answers to questionnaires distributed every month with activity reports, and final interviews. Results: The results of the analysis suggest that 1) it is feasible for senior citizens to carry a smartphone to collect their activity and location data, and participants did not feel stressed even when they did not have previous experience using the device; 2) activity reports are a promising way to help senior citizens reflect on their daily lives; 3) senior citizens can be highly atuned to erroneous numeric data captured by these devices, and 4) the ability to interpret visualisations of lifelog data can vary across participants. Conclusions: The findings of this study call for developing data literacy programs for senior citizens to facilitate their effective use of data-driven services.
