Influence of motion artifacts on photoplethysmographic signals for measuring pulse rates

One of the most important issues in the wearable healthcare sensors for continuous monitoring in daily life is motion artifact reduction. This paper presents an analysis of motion artifacts on PPG signals to find the suitable location for monitoring heart rates. The experiment system, which consists of PPG sensors and data acquisition system, was built to measure heart rate during controlled body motions such as walking. A reflective type PPG sensor was used to measure the pulse rate signal from several locations of the body including forehead, ear, neck, wrist, finger, and toe, and data were collected and analyzed to compare the effects of motion artifacts on signals. Pulse rates were estimated by counting the number of heartbeats in minute and comparing results with from the two states of stationary and moving conditions. The experiment results showed that forehead is the most suitable location for monitoring because it has less motion artifact than other locations. These results can be used to support the measurement of pulse rates to detect clinically significant heartbeat problems.