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Plain talk about
Autonomic Function Testing.

The WHAT, WHY, and HOW of Autonomic Function Testing.

WHAT is Autonomic Function Testing?


You may have heard the term “fight or flight” but there’s a lot more behind it than running away, or standing your ground. Did you know it is a term that applies to part of your nervous system?  Your Autonomic Nervous System is made of two main branches; Sympathetic (“Fight or Flight”) and Parasympathetic (“Rest and Digest”).  With everything you do, your bodily functions are programmed to have a certain response, and those responses are controlled by one of those 2 systems. For example, this is why your heart rate increases when you exercise, but also when you get scared or anxious.  It’s a specific set of physical responses programmed by your body to help you do what you’re doing.

Through an evaluation of your nervous system, Autonomic Function Testing measures whether or not your Autonomic systems are working right, and that your body properly responds to different conditions appropriately. Are any of your bodily functions overactive? Maybe underactive? And what does this mean long term? 


During each test, it looks at specific factors to evaluate the health and effectiveness of your nervous system.  Additionally, Autonomic Function Testing evaluates your overall cardiovascular health. How healthy are your heart and arteries? How is your physical and/or mental stress impacting your health? There can be silent risks that develop without any warning signs, but through Autonomic Function Testing your doctor can evaluate a lot of different issues that can come up.

WHY should I do this test?

It can be very dangerous when your nervous system is not properly responding to different conditions. Autonomic Function Testing is a thorough assessment of your nervous system, and can uncover a lot of hidden risks such as heart attack, stroke, sudden death, peripheral artery disease, etc. Autonomic balance can also give physicians a chance to evaluate how well your current treatment plan is working.

Uncovering these hidden risks earlier and more accurately can help you make lifestyle changes that will dramatically lower your chances of having a life-threatening issue.  It also gives your doctor information on your specific potential for future complications, and therefore be ready and aware to catch it before it’s too late.  Avoidance is not always possible, but awareness is the best defense.

HOW is the test performed?

Testing equipment:  These sensors are strictly receiving information

  • 2 blood pressure cuffs (ankle and arm) - these are evaluating the blood pressure in your arm and leg during the assessment.

  • 2 pulse oximeters (finger and toe) - these look at the oxygen level in your blood, as well as evaluate your artery health.

  • 3 lead EKG - 3 sticker electrodes will be put on your chest which listens to your heart work, as well as accurately evaluates your heart rate throughout the entire test.


Testing procedure:


Starting from a seated position, both the testing software and your technician will guide you through a series of simple testing phases:


  1. 4 minutes resting - just sit and relax, breathe normally and let the system see how your body is working at rest.

  2. 1 minute deep breathing - the software will ask you to breathe in for 5 seconds, and then breathe out for 5 seconds, for a 1 minute.  Just note that it’s harder to breathe in slowly, than it is to breathe out slowly, so focus on breathing in slowly through your nose, and then breathe out fully through your mouth.

  3. 2 valsalva maneuvers - Valsalva is not a well-known term, but you do it a lot.  Anytime you go to the bathroom, you build pressure through your stomach and most people tend to hold their breath.  This is exactly what Valsalva is, and the software will have you do this 2 times.  You will take a big breath in and then cut it off, and bear down.  After a few seconds, the software will ask you to breathe out forcefully.  It’s good to think about “blowing all the candles out on the cake in one shot”!  

  4. 2 minutes standing - All you have to do is stand up carefully, and stay standing for a couple minutes.  Sometimes people get dizzy when they stand up, but your technician will be checking and aware, and have you sit down if that’s the case.  

  5. Optional physical activity test: 30 seconds seated, 30 seconds standing, repeat - some offices will have an extended test that looks at how your heart rate and blood pressure respond when you sit and stand a couple times in a row.  It’s exactly that: sitting and standing twice and then you’re done!


*Some offices will perform this test from a special chair or table that rotates.  You will do most of the test laid back, until the last phase where instead of standing, your technician will rotate you upright.

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