Quality of the Wireless Electrocardiogram Signal During Physical Exercise in Different Age Groups

Electrocardiographic (ECG) recordings are usually obtained at rest. In many cases, real-time ECG monitoring in the home environment during daily life would be useful, but that requires a wireless device. The purpose of this paper is to evaluate the quality of the wireless ECG signals during physical activities. The test data were collected both in a normal exercise environment and in a radio frequency (RF)-shielded and noiseless environment. 30 test persons performed running, biking, or Nordic walking exercises in normal indoor conditions, while electrical activity of the heart and acceleration of the body were measured by a VitalSens VS100 device (InteleSens). The acceleration data were also acquired with a DogIMU movement sensor (Domuset). Six more persons were measured in an RF-shielded environment, while they followed a specific list of exercises to verify the tests of the first group. The list consisted of exercise movements, thought to introduce disturbance in the ECG signals. The collected data were classified into three quality classes, good (3%), moderate (66%), and poor (31%), based on the recognition of the QRS-complex and R-R intervals as well as the amount of disturbance. The accelerometer data were compared to the amount of noise in the ECG data. A clear correlation was found between increased noise and level of activity. Increasing age also appeared to decrease the ECG signal quality. Careful consideration of the quality of the data versus positive and negative features of wirelessness shows great potential for the wireless ECG in future home healthcare and fitness industries.