Some degree of dysfunction with the autonomic nervous system is probably very widespread, especially as we get older. For example, more than 25 percent of people over the age of 75 suffer from mildorthostatic hypotension, in which it may be harder for people to stand without feeling dizzy due to the autonomic nervous system’s inability to appropriately adjustblood pressure.
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Almost any medical problem—or even treatment—can impact the autonomic nervous system either directly or indirectly. A problem with the autonomic nervous system is calleddysautonomia. Before correcting the problem, though, it’s important to properly test to make sure that the nature of the dysautonomia is correctly understood.
Orthostatic Blood Pressure Measurement
If the blood pressure falls, it may not be a problem with the autonomic nervous system: there may just not be enough blood to maintain adequate pressure. The usual reason for this is dehydration, which is why we also check the pulse. If the blood pressure does fall, the pulse should increase as the body tries to increase blood pressure and get blood to the brain. If it doesn’t, there may be a problem with the reflex arc involving thevagus nerve, which has autonomic nerve fibers that control heart rate.
Other Bedside Tests
Using anelectrocardiogram(ECG or EKG) while doing some simple maneuvers can increase the sensitivity of tests for dysautonomia. For example, the ratio of the distance between two electrical waves on the 15th and 30th heartbeats after standing from a seated position can indicate a problem with the vagus nerve. This can also be done during deep breathing. Up to age 40, an exhalation to inspiration ratio of less than 1:2 is abnormal. This ratio is expected to decrease as we age and also decreases with even a very milddiabetic neuropathy.
Other techniques measure changes in blood pressure after muscular contraction for a few minutes, or after keeping a limb immersed in cold water.
Advanced Autonomic Testing
When bedside tests are insufficient, there are more involved diagnostic procedures available at some institutions. These may involve the patient’s being placed on atilt table, which allows the patient’s position to be changed rapidly and in a way that can be easily measured.
Skin conductance can be measured after a chemical is infused to make just that patch sweat in order to evaluate subtle differences between different regions of the body.
Sometimes serum levels of hormones like norepinephrine can be measured in response to a systemic stress, but such testing is unusual.
Sweat Tests
The sympathetic nervous system is responsible for causing secretion from sweat glands. Think of it as a way to ensure that our body stays cool enough to successfully run away from an attacking tiger.
Sometimes the sympathetic innervation to part of the body is lost, and this part no longer sweats. This is not always obvious, since perspiration may run from another region of the body to cover the part that no longer perspires. In a sweat test, the body is covered with a powder that changes color when sweating, making regional lack of perspiration more obvious. The downside is that this test is very messy.
Testing of Separate Body Parts
Because the autonomic nervous system involves almost every part of the body, it may be necessary to check how the autonomic nerves are working in one particular part rather than just the cardiovascular system.
If a problem with the autonomic nervous system is suspected and confirmed, it is likely that more testing will be needed to determine the cause. Rather than trying to just treat the dysautonomic symptoms, addressing the core cause of the illness is the best way to get the autonomic nervous system back in balance.
SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Hiitola P, Enlund H, Kettunen R, Sulkava R, Hartikainen S.J Hum Postural changes in blood pressure and the prevalence of orthostatic hypotension among home-dwelling elderly aged 75 years or older. Hypertens. 2009 Jan;23(1):33-9. doi:10.1038/jhh.2008.81. Epub 2008 Jul 24.Blumenfeld H, Neuroanatomy through Clinical Cases. Sunderland: Sinauer Associates Publishers 2002.Ropper AH, Samuels MA. Adams and Victor’s Principles of Neurology, 9th ed: The McGraw-Hill Companies, Inc., 2009.
Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Hiitola P, Enlund H, Kettunen R, Sulkava R, Hartikainen S.J Hum Postural changes in blood pressure and the prevalence of orthostatic hypotension among home-dwelling elderly aged 75 years or older. Hypertens. 2009 Jan;23(1):33-9. doi:10.1038/jhh.2008.81. Epub 2008 Jul 24.Blumenfeld H, Neuroanatomy through Clinical Cases. Sunderland: Sinauer Associates Publishers 2002.Ropper AH, Samuels MA. Adams and Victor’s Principles of Neurology, 9th ed: The McGraw-Hill Companies, Inc., 2009.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Hiitola P, Enlund H, Kettunen R, Sulkava R, Hartikainen S.J Hum Postural changes in blood pressure and the prevalence of orthostatic hypotension among home-dwelling elderly aged 75 years or older. Hypertens. 2009 Jan;23(1):33-9. doi:10.1038/jhh.2008.81. Epub 2008 Jul 24.Blumenfeld H, Neuroanatomy through Clinical Cases. Sunderland: Sinauer Associates Publishers 2002.Ropper AH, Samuels MA. Adams and Victor’s Principles of Neurology, 9th ed: The McGraw-Hill Companies, Inc., 2009.
Hiitola P, Enlund H, Kettunen R, Sulkava R, Hartikainen S.J Hum Postural changes in blood pressure and the prevalence of orthostatic hypotension among home-dwelling elderly aged 75 years or older. Hypertens. 2009 Jan;23(1):33-9. doi:10.1038/jhh.2008.81. Epub 2008 Jul 24.
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