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PubMed This is a summary of 19 peer-reviewed journal articles Updated
Endocrinology · Diabetic Autonomic Neuropathy

Autonomic Neuropathy: The Silent Risks

At a Glance

Diabetic autonomic neuropathy damages the nerves controlling your heart, blood pressure, and digestion. Key signs include a racing heart while resting, dizziness when standing up, and feeling full quickly, all of which can make managing your blood sugar much more difficult.

While most people associate diabetic neuropathy with foot pain, some of the most serious risks occur in the “silent” systems of your body. Autonomic neuropathy affects the nerves that control your heart, blood pressure, and digestion. Because these systems run automatically, damage to them can be difficult to notice until it becomes a significant safety issue.

The Heart: Cardiovascular Autonomic Neuropathy (CAN)

CAN occurs when the nerves that regulate your heart rate and blood pressure become damaged. This complication requires close monitoring because it can lead to severe health issues over time:

  • Heart Rhythm and Long-Term Cardiac Risks: CAN is a strong predictor of heart rhythm abnormalities and significantly increases your overall risk for severe cardiac events [1][2]. Close monitoring by a cardiologist is often recommended.
  • Orthostatic Hypotension: This is the clinical term for a sudden drop in blood pressure when you stand up, leading to dizziness, lightheadedness, or even fainting [3][4]. Actionable tip: If you experience this, try to stand up slowly and in stages—sit on the edge of the bed for a minute before standing, and stand holding onto a stable surface before walking.
  • Resting Tachycardia: You may notice your heart racing (a high pulse) even when you are sitting perfectly still or resting [5].
  • Kidney Risks: CAN is also an independent predictor of rapid kidney function decline, making it a critical “early warning” sign for your overall health [6][7].

The Stomach: Diabetic Gastroparesis

Gastroparesis occurs when nerve damage slows or stops the movement of food from your stomach to your small intestine [8]. This creates a “mismatch” that makes managing diabetes much harder:

  • Glycemic Variability: Because food isn’t being absorbed at a predictable rate, your blood sugar may stay low after a meal and then spike dangerously hours later once the food finally moves [9][10].
  • Symptoms to Watch For: You may experience early satiety (feeling full after just a few bites), frequent bloating, nausea, or unexplained vomiting [11][12].

How Doctors Monitor the “Silent” Risks

Because these symptoms are often hidden, your care team uses specialized tools to see what is happening inside:

  • Ewing’s Tests: A series of simple tests that measure how your heart rate and blood pressure respond to specific actions, like deep breathing or standing up [13][14].
  • Heart Rate Variability (HRV): By analyzing the tiny millisecond changes between your heartbeats, doctors can detect early signs of CAN [15][16].
  • Sudoscan: This non-invasive test measures sweat gland function, which is often one of the first signs of autonomic nerve damage [17][18].
  • Gastric Scintigraphy: To diagnose gastroparesis, you may be asked to eat a meal containing a tiny amount of radioactive material so a camera can track exactly how long it takes for your stomach to empty (usually over 4 hours) [11][19].

If you notice a racing heart, dizziness when standing, or early fullness, it is essential to share these with your doctor immediately. They are critical signals that your autonomic nerves need attention.

Common questions in this guide

What is cardiovascular autonomic neuropathy (CAN)?
Cardiovascular autonomic neuropathy occurs when nerve damage from diabetes affects your heart rate and blood pressure regulation. It can cause a racing heart while resting, dizziness when standing up, and an increased risk for severe cardiac events.
Why does diabetes make me feel dizzy when I stand up?
Nerve damage from diabetes can cause orthostatic hypotension, which is a sudden drop in blood pressure when you change positions. This drop makes you feel dizzy, lightheaded, or as if you might faint when getting out of bed or standing up from a chair.
How does gastroparesis affect my blood sugar?
Gastroparesis slows down how fast food moves from your stomach to your intestines. Because food is absorbed unpredictably, your blood sugar might stay low right after a meal and then spike dangerously several hours later when the food finally digests.
What tests check for diabetic autonomic neuropathy?
Doctors use non-invasive tools like Ewing's tests and Heart Rate Variability (HRV) analysis to check your heart's nerve function. They may also use a Sudoscan to test sweat gland function or a gastric scintigraphy to measure how fast your stomach empties.
Why does my heart race when I am sitting still or resting?
A high heart rate while you are sitting still, known as resting tachycardia, is a common early sign of cardiovascular autonomic neuropathy. It happens because the nerves that normally keep your resting heart rate steady have been damaged.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Can we screen for Cardiovascular Autonomic Neuropathy (CAN) using Ewing tests or a Heart Rate Variability (HRV) analysis?
  2. 2.Why does my heart rate seem to stay high even when I am sitting still or resting?
  3. 3.If I am experiencing dizziness when I stand up, should we test for orthostatic hypotension?
  4. 4.Is my gastroparesis causing my blood sugar levels to spike and dip unpredictably after meals?
  5. 5.Should we perform a 4-hour gastric scintigraphy to officially measure how fast my stomach is emptying?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (19)
  1. 1

    Intensive risk factor management and cardiovascular autonomic neuropathy in type 2 diabetes in the Action to Control Cardiovascular Risk in Diabetes trial: A post-hoc analysis.

    Aso Y

    Journal of diabetes investigation 2021; (12(8)):1316-1318 doi:10.1111/jdi.13565.

    PMID: 33949126
  2. 2

    Impaired hypoxic ventilatory drive induced by diabetic autonomic neuropathy, a cause of misdiagnosed severe cardiac events: brief report of two cases.

    Schubert L, Laroche S, Hartemann A, et al.

    BMC cardiovascular disorders 2021; (21(1)):140 doi:10.1186/s12872-021-01944-4.

    PMID: 33731006
  3. 3

    Cardiac autonomic neuropathy: impact on severe hypoglycemic unawareness and orthostatic hypotension in diabetic dysautonomia, a case series and review.

    Wu C, Devireddy R, Zazaian A, et al.

    Cardiovascular endocrinology & metabolism 2024; (13(4)):e00319 doi:10.1097/XCE.0000000000000319.

    PMID: 39574826
  4. 4

    Cardiovascular autonomic neuropathy and the risk of diabetic kidney disease.

    Cho I, Lim S, Kwon M, et al.

    Frontiers in endocrinology 2024; (15()):1462610 doi:10.3389/fendo.2024.1462610.

    PMID: 39329106
  5. 5

    Autonomic neuropathy in diabetes.

    Tannus LRM, Cobas RA

    Archives of endocrinology and metabolism 2025; (70(special 1)):e250406 doi:10.20945/2359-4292-2025-0406.

    PMID: 41313194
  6. 6

    Cardiac autonomic neuropathy and risk of incident heart failure among adults with type 2 diabetes.

    Kaze AD, Yuyun MF, Erqou S, et al.

    European journal of heart failure 2022; (24(4)):634-641 doi:10.1002/ejhf.2432.

    PMID: 35064959
  7. 7

    Cardiovascular Autonomic Neuropathy and Risk of Kidney Function Decline in Type 1 and Type 2 Diabetes: Findings From the PERL and ACCORD Cohorts.

    Tang Y, Ang L, Jaiswal M, et al.

    Diabetes 2024; (73(5)):751-762 doi:10.2337/db23-0247.

    PMID: 37467433
  8. 8

    Gastrointestinal autonomic neuropathy in diabetes.

    Marathe CS, Jones KL, Wu T, et al.

    Autonomic neuroscience : basic & clinical 2020; (229()):102718 doi:10.1016/j.autneu.2020.102718.

    PMID: 32916479
  9. 9

    Classification of Gastroparesis from Glycemic Variability in Type 1 Diabetes: A Proof-of-Concept Study.

    Cichosz SL, Hejlesen O

    Journal of diabetes science and technology 2022; (16(5)):1190-1195 doi:10.1177/19322968211015206.

    PMID: 33993744
  10. 10

    The impact of gastroparesis on diabetes control: Patient perceptions.

    Homko C, Siraj ES, Parkman HP

    Journal of diabetes and its complications 2016; (30(5)):826-9.

    PMID: 27166926
  11. 11

    AGA Clinical Practice Guideline on Management of Gastroparesis.

    Staller K, Parkman HP, Greer KB, et al.

    Gastroenterology 2025; (169(5)):828-861 doi:10.1053/j.gastro.2025.08.004.

    PMID: 40976635
  12. 12

    United European Gastroenterology (UEG) and European Society for Neurogastroenterology and Motility (ESNM) consensus on gastroparesis.

    Schol J, Wauters L, Dickman R, et al.

    Neurogastroenterology and motility 2021; (33(8)):e14237 doi:10.1111/nmo.14237.

    PMID: 34399024
  13. 13

    Sudoscan as substitute for quantitative sudomotor axon reflex test in composite autonomic scoring scale and its correlation with composite autonomic symptom scale 31 in type 2 diabetes.

    Huang CC, Lai YR, Cheng BC, et al.

    Neurophysiologie clinique = Clinical neurophysiology 2023; (53(6)):102915 doi:10.1016/j.neucli.2023.102915.

    PMID: 37926016
  14. 14

    Evaluation of the Degree of Agreement of Four Methods for Diagnosing Diabetic Autonomic Neuropathy.

    Peng Y, Liu YS, Wu MY, et al.

    Frontiers in neurology 2021; (12()):637099 doi:10.3389/fneur.2021.637099.

    PMID: 34113304
  15. 15

    Time- and frequency-domain measures of heart rate variability predict cardiovascular outcome in patients with type 2 diabetes.

    Cha SA, Park YM, Yun JS, et al.

    Diabetes research and clinical practice 2018; (143()):159-169 doi:10.1016/j.diabres.2018.07.001.

    PMID: 30006307
  16. 16

    Heart rate variability in type 2 diabetes mellitus: A systematic review and meta-analysis.

    Benichou T, Pereira B, Mermillod M, et al.

    PloS one 2018; (13(4)):e0195166 doi:10.1371/journal.pone.0195166.

    PMID: 29608603
  17. 17

    The Importance of Evaluating Sudomotor Function in the Diagnosis of Cardiac Autonomic Neuropathy.

    Nica AE, Rusu E, Dobjanschi CG, et al.

    Cureus 2024; (16(3)):e57226 doi:10.7759/cureus.57226.

    PMID: 38686272
  18. 18

    A cardiac risk score based on sudomotor function to evaluate cardiovascular autonomic neuropathy in asymptomatic Chinese patients with diabetes mellitus.

    Yuan T, Li J, Fu Y, et al.

    PloS one 2018; (13(10)):e0204804 doi:10.1371/journal.pone.0204804.

    PMID: 30281621
  19. 19

    Gastroparesis.

    Camilleri M, Chedid V, Ford AC, et al.

    Nature reviews. Disease primers 2018; (4(1)):41 doi:10.1038/s41572-018-0038-z.

    PMID: 30385743

This page provides educational information about diabetic autonomic neuropathy and is not intended as medical advice. Always discuss your symptoms and test results with your healthcare provider.

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