What if the Person Taking a Lie Detector Test has a Medical Condition?

The polygraph test

There’s a lot of “fake news” about how to cheat or fool a polygraph exam. It is commonly stated that you can’t take the test successfully if you have a medical condition. The fact is your medical condition can influence a lie detector test, so you need to be upfront about medical problems.

Will the test aggravate a medical condition?

No. The lie detector equipment and procedure will not cause any direct injury to the testing subject. There are no needles or injections. The only possible discomfort is the pressure from a standard blood pressure cuff on the arm.

What about medications?


Medications that affect blood pressure, blood flow, and heart rate can influence a polygraph test. These include anti-anxiety, anti-hypertensive, and illegal drugs. For some people, caffeine and nicotine can affect brain/body systems.

However, as LiveStrong points out, “the improved technology of the polygraph test with its ability to discern subtle changes in response to questions can uncover pre-medication.” So, an experienced lie detector expert will determine the subject’s medication regimen in the pre-test screening.

What if you have a medical condition?

There is always some stress in a polygraph test. And, for a few people, the lie detector process can be unduly stressful. High-stress situations, real or imagined, can affect those with medical conditions that are sensitive to stress, like some heart conditions.

Depending on medical conditions disclosed by the polygraph subject, most examiners would require an approval from the treating physician prior to conducting an exam on someone with such a condition.

There is nothing painful or physically harmful in a polygraph test. There is nothing to fear physically or psychologically. A lie detector test simply records your physiological responses when asked questions.

It reports changes in respiration, heart rate, and blood pressure. And, the lie detector expert measures those responses against responses to pre-screening questioning.


As David Brown said in The Washington Post, “It’s an axiom in medicine that no diagnostic test is perfect.” Still, when the lie detector subject is honest and forthcoming about all medical conditions, medication intake, physical concerns, the polygraph examiner has the data needed to make more accurate conclusions. –