In this paper the possibility of person identification based on biosignal is investigated. The work focus on the analysis of the changes in intervals between successive R-waves of electrocardiogram (ECG) recorded by wearable electronics in form of a necklaces. The main idea behind this project is to find efficient tool which may prevent sudden consciousness loss episodes or even sudden death episodes related to rapid temperature changes. Proposed method relays on the estimation of the RR interval changes in time with three approximation functions. Then, the identification of a person is performed based on the parameters of the utilized estimation functions.