There are no scientific studies on the effects of tachycardia (rapid beating of the heart) or any other medical condition on polygraph results. However, polygraph "testing" has not been proven through peer-reviewed field studies to reliably distinguish liars from truth-tellers in populations who have no such medical conditions. Indeed, the scientific consensus viewpoint is that polygraph testing has no scientific basis.

Before your relative agrees to submit to a police-administered polygraph interrogation, please refer him to our free book, The Lie Behind the Lie Detector, which exposes the trickery behind this pseudoscientific procedure. As used by law enforcement agencies, the polygraph often serves as little more than a pretext for getting a suspect into an interrogation room without a lawyer present, and your family member would probably be well-advised to refuse the polygraph.