There is provided a audio pacing device including a sensing unit, such as heart rate monitoring unit, to obtain a parameter, such as heart-beat rate (pulse), of a user in physical exercise, a memory to store a plurality of audio signals having predetermined tempo indications (e.g. beats per minute values); and a processing unit configured to (1) determine whether the intensity of the parameter of the user should be increased, decreased or maintained by using the parameter of the user from the heart rate monitor and a predetermined reference value, and (2) dynamically select and render an audio signal having (or adjusted to have) an audio-tempo that enables the user to accordingly increase, decrease or maintain exercise intensity, respectively.