Sleep Monitoring in Adults Using Wearables and Unobtrusive Technology

Sleep is a complex physiological process that plays a fundamental role in maintaining homeostasis and overall health. It has an internal structure characterized by sleep stages, which is often affected by either the high demands of the current 24-h society or by different sleep disorders such as sleep apnea. These disturbances to the regular sleep structure have been strongly associated with reductions in cognitive and behavioral performance, attention deficit, depression, nocturia, memory loss, snoring, and cardiovascular diseases. Therefore, it is crucial to identify sleep problems in an early stage before the overall health is compromised in an irreversible way. Currently, sleep disorders are diagnosed using polysomnography (PSG), which is the gold-standard sleep test usually recorded in a sleep laboratory. This test is often associated with elevated costs and reduced comfort. With this in mind, many studies have focused on the development of wearables and unobtrusive technologies that can be used at home and that can monitor sleep during more than one single night. This chapter discusses unobtrusive state-of-the-art sensors and algorithms for sleep monitoring in adults, with a special focus on heart rate, respiration, and blood oxygenation monitoring.