*2.1. Wearable Devices*

Globally-accepted wearable devices to monitor sedentary behaviour are ActiGraph and actiPAL [23]. Matthews et al. [24] used the ActiGraph device to record the acceleration information and estimate the body movement. The wearable device was set to provide information in 1-min epochs. Participants wear this on their right hip attached with an elastic belt. After the collection of the data, the device was attached to computer, and data were analysed using specially-developed software. This mechanism is intrusive, and the user needs to attach the device to his/her body. Chelsea et al. [25] explored how the DigMem system is used to successfully recognize activity and create temporal memory boxes of human experience, which can be used to monitor sedentary behaviour. Users can track where they exactly were, what they were doing and how their bodies were reacting. Their solution is comprised of multimodal sensors including GPS, camera, ECG monitor, environmental sensor, sound and accelerometer. This notwithstanding, such a system is still not a handy solution to embrace in daily routines in order to promote self-awareness.

Stratton et al. [26] created an intelligent environment to monitor and manipulate the physical activity and sedentary behaviour. They also discussed the broad range of approaches already designed to increase physical activity among different populations. Their proposed solution is obtrusive due to the need to wear an additional sensor to monitor the sedentary behaviour. Such methods are intrusive and unable to process the sensor data inside the devices. Furthermore, they provide limited information about the sedentary behaviour in everyday routines. One of the drawbacks of wearable devices is the inability to detect the contextual information.
