Using Low-Cost Technology Devices for Monitoring Sleep and Environmental Factors Affecting It: A Systematic Review of the Literature

Low-cost technology devices, such as smartphones (SPs) and smart watches (SWs), are widely used today to monitor various health effects and environmental risk factors associated with them. However, the efficacy of using these devices as monitoring tools is largely unknown. The present study attempts to narrow this knowledge gap by reviewing recent studies in which low-cost technological tools were used to monitor sleep and associated environmental risk factors. The study focuses on peer-refereed articles that appear in three major scientific databases, Web of Science, Scopus, and ScienceDirect, and were published between 2002 and 2022. Of the 15,000+ records retrieved from these databases by the systematic literature review (PRISMA) search, 15 studies were identified as the most relevant and consequently analyzed. The analysis shows that nighttime light pollution and noise are environmental factors that are most commonly monitored by low-cost technology tools (eight studies), followed by temperature monitoring (seven studies), humidity monitoring (seven studies), and CO₂ monitoring (four studies). In eight studies, tandems of SPs and SWs were used to monitor sleep, while in six studies, data obtained from SPs and SWs were compared with records obtained from conventional monitoring devices. In general, SP and SW measurements were found to be fairly accurate for monitoring sleep and light pollution and less accurate for monitoring noise. At the same time, no studies conducted to date and analyzed in this review demonstrated the effectiveness of SPs and SWs in monitoring ambient temperature, humidity, and air pressure. Our general conclusion is that although SPs and SWs often lack the precision of professional instruments, they can nevertheless be used for large-scale field research and citizen science initiatives, while their feasibility and effectiveness for monitoring several environmental attributes have yet to be determined.