Can Caffeine Affect Polygraph Test Results?


Is your employer polygraphing you at work? If they’ve taken the necessary steps to comply with the EPPA and you agree to the terms, you’ll need to prepare yourself for the exam. Undergoing a polygraph is a harrowing experience for most people. It involves you sitting in a chair, wired up to a machine, with a stranger asking personal questions.

You can walk into the exam room, meet the examiner, and run through the basics of the polygraph procedures. It pays to have some level of preparation before undergoing the lie detector test. The better prepared you are for the exam, the more control you have over the body’s natural “fight-or-flight” response when the examiner starts asking your questions.

The “fight-or-flight” response is a natural instinct we all have in us. It activates when we feel stressed, and there’s nothing we can do to stop it. The intensity of the fight-or-flight reaction depends on the amount of stress in the experience and what we do to prepare for it.

We can use several methods to better prepare ourselves for the polygraph exam and the reaction it brings to our physiology. Preparing for the polygraph isn’t illegal or underhanded, and it doesn’t show your indication to “cheat” on it.

One of the best ways to ensure you have a positive experience in your polygraph is to monitor your diet and behavior on the morning of the exam. Most of us wake up to a cup of coffee in the morning; it’s a pastime enjoyed by more than 60% of Americans each day. However, coffee, unless you drink decaf, contains the nervous system stimulant caffeine.


What Is Caffeine and Where Do You Find It?

Caffeine is a common ingredient in coffee and energy drinks. You don’t need us to tell you about its effects on the body. A good dose of caffeine in the morning clears the cobwebs, preparing us to take action during the day. The mental and physiological effects of caffeine on productivity are well documented, and it’s one of the reasons why employers instituted “coffee breaks” during the workday.

However, you don’t need us to tell you about the adverse effects of this chemical either. We’re sure you’ve had a day or two when you drank too much coffee or had that second can of Red Bull, leading to caffeine rampaging your body and mind, leaving you in a frenzy.

Caffeine is a nervous system stimulant, heightening your physiological responses. For instance, an hour after drinking a caffeinated beverage, the chemical finds its way into your bloodstream, instituting its effects. Your blood pressure increases, your breath quickens, and your pupils dilate.

Drink too much of the stuff, and you start to feel like your heart will jump out of your chest. You become anxious, and you can’t sit still. You might even decide that you’re dying, depending on the dose. Caffeine can be our friend or enemy, depending on our relationship with it.

If you’re inexperienced with caffeine and only have a cup of coffee from time to time, drinking one cup is enough to give you a surge of energy throughout your body. If you’re accustomed to the stuff, you could handle three to four times that dose and still feel comfortable. Everyone’s tolerance to caffeine is different.


Caffeine and its Effect on the Autonomic Nervous System

As a nervous system stimulant, caffeine affects the “autonomic” nervous system (ANS). The ANS comprises the sympathetic (SNS) and parasympathetic (PSNS) nervous systems. The ANS is responsible for the autonomic functions in our body, such as breathing and blinking, you don’t have to think about taking these actions, and it’s the ANS responsible for that convenience.

The PSNS controls the “rests and digest” functions of our body, meaning your ability to fall asleep and digest food. The SNS initiates the “fight-or-flight” response through its interaction with the hormonal system.

When we drink too much caffeine, we experience effects on both the PSNS and the SNS. For the PSNS, you’ll notice you feel more awake and start going to the bathroom more often due to the diuretic effects of caffeine.

With the SNS, you start feeling more responsive to the world around you. Your senses become on edge, and you might feel a little jumpy if you have too many cups of coffee. Unfortunately, that’s not what we’re looking for when we’re about to take a polygraph.

When you step into the exam room, you want to feel confident and at ease with the situation. While we all have a fear of the unknown, that’s a normal human response. However, arriving at the exam feeling jittery and anxious could interfere with the polygraph instrumentation and software and the examiner’s interpretation of its results.


Caffeine and its Interference with the Sympathetic Nervous System and Polygraph Results

Undergoing a polygraph is a nerve-wracking experience for most people. Even if you’re innocent of any crime and live a responsible life with nothing to hide, you’ll feel nervous walking into the polygraph exam room; it’s just human nature.

Since you’re feeling uptight about the situation, your autonomic and parasympathetic nervous system takes control of the situation. Your PNS activates the hypothalamus, signaling it to produce more adrenaline and cortisol, flooding your bloodstream with these biochemicals.

The purpose of this reaction is to activate the “fight-or-flight” response. As a result, your body primes itself to defend against assaults from attackers or run away from them. While the fight-or-flight response usually occurs when you experience a threat, such as someone following you home, causing you to run away at top speed, it also activates when you walk into the polygraph exam room.

The PSNS primes the fight-or-flight response, waiting for a stimulus to push it over the edge and cause you to stand your ground or run away. Polygraph technology and examiners leverage your PSNS response to determine if you’re being deceptive when they ask you questions.

If they ask you a question and you feel like you have to lie, the fight-or-flight response increases your breath rate, elevates your heartbeat, and your skin starts to sweat. The polygraph machine picks up this heightened physiological activity, presenting the information as a sign of deception to the examiner.

So, if you decide to have a cup of coffee a few minutes before entering the exam room, you’re asking for trouble. The stimulant’s effects on the nervous system add to the efficacy of the fight-or-flight response produced by the nervous system. Essentially, you’re making your self overly-nervous during the exam process. Caffeine creates anxiety when we have too much of it, and feeling anxious before you enter the exam room will affect the outcome of the lie detector test.

As a result, there’s a higher chance you’ll activate the PSNS and the fight-or-flight response, producing signs of deception when you’re just feeling nervous due to the additional caffeine in your system.


How Long Do I Wait Before Using Caffeine and Taking a Polygraph?

Caffeine ingested through energy drinks or coffee usually takes around 45 minutes to an hour to become active in your bloodstream, depending on your metabolism. It also has a four to six-hour “half-life” in the body. That means it takes around eight to 12 hours to dissipate from your bloodstream entirely.

So, if you drink a cup of coffee the hour before the polygraph exam, the caffeine starts hitting your bloodstream as you sit down for the exam. It activates the nervous system, and the SNS, priming the fight-or-flight response.

Since you’re in an unknown environment and under pressure, you’re more likely to enter the fight-or-flight response, even though you have no reason to do so. As a result, you might fail the polygraph because you feel overly nervous.

For instance, the examiner might ask you if you’ve ever stolen anything. Your mind flashes back to that time when you swiped a candy bar from the store as a kid without paying for it. The fight-or-flight response activates, and the physiological response from your body alerts the polygraph machine, causing the examiner to investigate the issue further.

Their continued pressure on you begins to look more and more like you’re being deceptive, even though you have nothing to be worried about. You end up failing the exam, and your employer now has an unfavorable opinion of you, even though it’s misinterpreted and misguided.


The Reality of Nervousness in the Polygraph Exam

In this scenario, where you’ve done nothing wrong but had too much caffeine, you don’t have to worry about failing the polygraph. The examiner will likely pick up that you’re nervous. They ask you why, and you’ll respond by telling them you had too much coffee before the exam.

They’ll do their best to calm you down and make you feel at ease. The sensitivity of the polygraph machine can tell the difference between being nervous and being deceptive. A talented and experienced examiner knows the pressure you’re under, and they’ll ensure that they do everything to make you feel comfortable again.

In a worst-case scenario, they’ll tell you to re-take the test at another stage when you don’t have caffeine rampaging through your system. They’ll also inform your boss of the reasons for the retest, and you won’t have to worry about them firing you.


Will My Morning Cup of Coffee Affect My Performance in My Lie Detector Test?

If you drink coffee or energy drinks daily, you’ll have a different response to the caffeine than someone who consumes these beverages from time to time. We build a tolerance to caffeine, and our body learns how to cope with its stimulating effects on the nervous system.

If you’re going into the office to take a polygraph that day, you don’t have to avoid your morning cup of coffee out of fear of failing the lie detector test. The best course of action on test day is to stick to your routine. If that involves a morning cup of Joe, stick to that ritual.

However, it’s common for people to feel tired the morning of the test because they might not get enough sleep the night before. The impending concern of the polygraph, even if you have nothing to hide, may cause sleeplessness.

So, it’s common for people to wake up feeling a bit groggy, requiring them to have an extra cup or two of coffee to help them refresh their minds. You might even stop past Starbucks on the way to the office and get a triple shot espresso to wake you up.

This behavior is a mistake. The extra caffeine outside our normal daily consumption will ramp your nervous system into overdrive, causing the priming of the PSNS and the fight-or-flight response. The effects of the extra caffeine become noticeably worse if you’re not a regular coffee or energy drink user.

Stick to your routine on test day and avoid consuming extra coffee or energy drinks. This strategy helps to remove any anxiety you might feel from drinking too many caffeinated beverages.


How to Minimize the Impact of Caffeine on Polygraph Tests

Being dehydrated or hungry also affects the body’s response to consuming caffeinated beverages. If your body needs more water in your system or you have an empty stomach, the caffeine gets into your bloodstream faster and has a more pronounced effect.

So, on the morning of your exam, make sure you have breakfast and hydrate yourself properly with water. Have your morning cup of coffee, but stick to one, don’t overdo it. Drink water up until your exam, and ensure your morning meal includes healthy fats.

Fats digest slower in the bloodstream and affect how your body absorbs caffeine in coffee. The fats slow the release of the chemical into your blood, giving you a smooth curve of energy rather than having it hit you like a freight train.

If you’re feeling nervous before the exam, tell the examiner. They’ll initiate you to the polygraph process, putting your mind at ease and removing the anxiety.

Uncover the Truth with a Professional Lie Detector Test – Our Carefully Vetted Examiners Ensure Your Peace of Mind.