Below is an in-depth discussion of what a lie detector machine measures and what a polygraph expert looks for.<\/p>\n\n\n\n Whether the polygraph machine is the analog kind or the more modern computerized type, it’s designed to observe and record the cardiovascular activity of the individual \u2014 the examinee \u2014 that it’s strapped to.<\/p>\n\n\n\n That’s because various emotions of a person can have an effect on the heart and its behavior.<\/p>\n\n\n\n And one of them is the feeling of guilt, which the vast majority of the population experiences when attempting to look and sound honest when telling a lie. Being guilty can be stressful to the body, and being stressed can cause all kinds of stress hormones to be produced. Many of these hormones can impact cardiovascular activity.<\/p>\n\n\n\n When being non-truthful, as a result, your blood pressure increases. And when your blood pressure increases, your heart rate tends to follow suit \u2014 it beats more than usual per minute.<\/p>\n\n\n\n It’s due to this why both the blood pressure and heart rate are monitored during a lie detector examination.<\/p>\n\n\n\n The machine can pick up changes in their readings, which can help the examiner determine whether or not the examinee could be fabricating lies. <\/p>\n\n\n\n But it’s important to note that changes in the blood pressure and heart rate can be due to many things, not just when answering crime-related questions falsely to cover up the truth.<\/p>\n\n\n\n Read Also: 10 Medical Conditions That Affect a Polygraph<\/a><\/strong><\/p>\n\n\n\n Notice that cuff that a doctor places around your upper arm when taking your blood pressure? Well, one of the different medical instruments integrated into the lie detector machine looks exactly like that thing.<\/p>\n\n\n\n The name: cardiosphygmograph. The function: to measure cardiovascular activity.<\/p>\n\n\n\n Sometime during the pretest phase of the polygraph examination, the examiner will place the cuff around the examinee’s arm. And during the question and answer stage, the cuff remains inflated. This is necessary in order for it to be able to monitor a couple of important physiologic changes in the individual.<\/p>\n\n\n\n One of the things that a cardiosphygmograph measure is blood pressure. It works by observing two pressures in the brachial artery, which is a major blood vessel supplying blood to your hand, forearm and upper arm:<\/p>\n\n\n\n Other than the blood pressure, the cardiosphygmograph is also capable of measuring the heart rate, too. Also referred to as the pulse rate, the heart rate is the number of times your heart beats per minute.<\/p>\n\n\n\n Both the blood pressure and heart rate are very important polygraph measurements.<\/p>\n\n\n\n Except for certain people such as those who are psychopaths, sociopaths and pathological liars, telling a lie can cause a feeling of guilt. In turn, this can cause stress in the body. The release of stress hormones in the bloodstream can momentarily increase an individual’s blood pressure.<\/p>\n\n\n\n This is the reason why your blood pressure is one of the physiologic processes that a polygraph monitors.<\/p>\n\n\n\n Because of this, it’s important for the lie detector test examiner to establish the examinee’s baseline blood pressure when telling the truth and the baseline blood pressure when telling a lie. Such is done during the pretest phase by asking irrelevant questions that require no lying and control questions that can usually force someone to lie.<\/p>\n\n\n\n Each time the blood pressure reading spikes, chances are that the examinee is lying.<\/p>\n\n\n\n It’s not just telling a lie, however, that can cause your blood pressure to rise temporarily but many other things, too. The following are some examples of those that can lead to momentary blood pressure spikes:<\/p>\n\n\n\n Various medications can also have an impact on the blood pressure of an individual. Leading the list are antihypertensive or blood pressure medications, the kinds that doctors prescribe to individuals with hypertension, which is characterized by a higher than normal blood pressure.<\/p>\n\n\n\n A hypertensive individual tends to have a systolic blood pressure reading of 130 mmHg or higher and a diastolic blood pressure reading of 80 mmHg or higher most of the time.<\/p>\n\n\n\n Other medications can also affect blood pressure. Some examples include:<\/p>\n\n\n\n If you are taking any of the above-mentioned drugs or medications and about to undergo a lie detector test, make sure that you inform the examiner about it during the pretest phase.<\/p>\n\n\n\n When stressed, one of the stress hormones the body produces is adrenaline. What the said hormone does is trigger the body’s fight or flight response, which is a primitive physiologic reaction to just about anything that is perceived as frightening or stressful, such as a threat or a hazard.<\/p>\n\n\n\n To prepare the body for either fighting or fleeing, the air passages dilate to introduce more oxygen to the muscles. The peripheral blood vessels, meanwhile, contract in order to redirect blood to the major muscle groups.<\/p>\n\n\n\n These reactions that adrenaline causes can elevate the heart rate.<\/p>\n\n\n\n Since lying is basically a form of stress, just like what was mentioned earlier, your heart rate increases each time you attempt to deceive someone, such as a polygraph examiner. And this is the reason why the number of times the heart beats per minute is one of the things that a lie detector instrument measures carefully.<\/p>\n\n\n\n However, because the idea alone of undergoing a polygraph test can be nerve-racking, it’s not unlikely for your heart rate to be faster than usual. Does this mean the examiner will find you guilty?<\/p>\n\n\n\n Not necessarily.<\/p>\n\n\n\n When establishing the baseline physiologic readings during the pretest phase of the examination, the examiner will attempt to determine your usual heart rate when in a relaxed state or telling the truth while answering irrelevant questions. If nervous because of the test, the professional will take this into consideration.<\/p>\n\n\n\n Your already high heart rate will increase further when being deceitful anyway, which means that there is very little to no chance for an experienced polygraph examiner to be confused with your rapid heart rate.<\/p>\n\n\n\n![\"polygraph](\"https:\/\/truthorlie.com\/wp-content\/uploads\/polygraph-test-1406172881-1024x768.jpeg\")
<\/figure>\n\n\n\nCardiovascular Activity<\/h2>\n\n\n\n
1. Cardiovascular Activity<\/h3>\n\n\n\n
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2. Blood pressure<\/h3>\n\n\n\n
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3. Heart rate<\/h3>\n\n\n\n
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