An illumination source may be configured to illuminate the skin of the user. An illumination detector may detect electromagnetic radiation reflected of the skin of the user. A compensation module may be configured to determine the position of the skin of the user relative to the illumination detector. A processor may be configured to determine a heart rate of the user by analyzing information corresponding to an amount of the electromagnetic radiation detected by the illumination detector. The processor may also determine the heart rate of the user by compensating for the position of the skin of the user as determined by the compensation module.
