Dear Anonymous,

I have always advocated telling the truth and like yourself, have been found "inconclusive" and "not within acceptable parameters."   I was found to be acceptable at a later date.  At no time did I use countermeasures but I was accused of using countermeasures which indicated to me during my experiences that they are "guesses" or "hunches" but not based on discernable readings.

This is exactly why the polygraph used as a pre-screening device is a 50/50 crapshoot.  If you were a spy with unlimited access to a polygraph examiner and could "practice", you would be able to manipulate your blood pressure.  The ability to control ones heart rate and blood pressure is actually practiced to reduce anxiety and is in some American Heart Association handouts and studies.  This technique requires a dedicated effort over a period of months and you must have some way of getting positive or negative feedback by having someone take your blood pressure as you practice.  While repeated blood pressure readings over short amounts of time will affect the exact accuracy of the numbers, the overall trends (used in polygraph examinations) will be noticeable.  A spy will have no shortage of resources to accomplish this but the average government applicant does not.   The argument has been made that the polygraph will not stop any spies but has stopped many good applicants with false positives.

All of this is moot in the polygraph exam because the examiner still has no absolute way of knowing if the response is due to fear, deception , or just thinking about the subject.  There are expert psychologist who have spent their whole life studying these issues who would never claim to be able to distinguish truths from lies based only on physical reactions.

It is not science, it is an interrogation and intimidation tool.

I can assure you that if given enough chances, you will randomly produce an "acceptable chart". This has nothing to do with lying or telling the truth.

Much of your anxiety is centered around the fact that you were "told" verbally that you had responses to certain questions.  This in itself could be a mind game. 

Controlling your blood pressure is in no way a sure fire method to overcome the problems you state.

Regards.