Smartphone photoplethysmography: Toward effective utilization in daily life measurement

Abstract

The advent of the smartphone, a compact but powerful and multifunctional computing device, permits the measurements of various physiological indices using a commercially available device alone. This is achieved by using built-in flash LED as a light source and built-in CMOS camera as a photo detector, and is called smartphone photoplethysmography (PPG). Although smartphone PPG is so easy that even a non-specialist can operate by oneself in daily life, it should be used with sufficient knowledge of its effectiveness and limitation. Otherwise, users may encounter unpredictable pitfalls. In this review article, we describe the basics of smartphone PPG in terms of the general background of PPG, restrictions especially for smartphone PPG, and caution during measurement, which are essential information for effective daily life measurement.