What are the symptoms of hypoglycemia?

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From the Guidelines

Symptoms of Hypoglycemia

Hypoglycemia is characterized by shakiness, irritability, confusion, tachycardia, sweating, and hunger as its primary symptoms.

  • These symptoms can vary in severity and may not always be present, especially in individuals with impaired hypoglycemia awareness 1.
  • Level 1 hypoglycemia, defined as a blood glucose concentration <70 mg/dL (<3.9 mmol/L) and ≥54 mg/dL (≥3.0 mmol/L), may exhibit these symptoms, while Level 2 hypoglycemia, with a glucose concentration <54 mg/dL (<3.0 mmol/L), is associated with neuroglycopenic symptoms that require immediate action 1.
  • It's essential to note that some individuals, particularly those with long-standing diabetes or recurrent hypoglycemia, may experience impaired hypoglycemia awareness, where they do not exhibit typical symptoms of hypoglycemia, making it crucial to monitor glucose levels regularly 1.
  • The symptoms of hypoglycemia can be inconvenient or frightening for patients with diabetes and, if left untreated, can progress to loss of consciousness, seizure, coma, or death 1.

From the Research

Symptoms of Hypoglycemia

The symptoms of hypoglycemia can be classified into two main categories: neurogenic (autonomic) and neuroglycopenic symptoms.

  • Neurogenic symptoms are the results of the perception of physiologic changes caused by the autonomic nervous system's response to hypoglycemia, and include:
    • Tremulousness
    • Palpitations
    • Anxiety
    • Sweating
    • Hunger
    • Paresthesias 2
  • Neuroglycopenic symptoms are the results of brain glucose deprivation itself, and include:
    • Confusion
    • Sensation of warmth
    • Weakness or fatigue
    • Severe cognitive failure
    • Seizure
    • Coma 2

Common Symptoms

Other studies have also identified common symptoms of hypoglycemia, including:

  • Autonomic symptoms:
    • Hunger
    • Palpitations
    • Tremor
    • Sweating 3
  • Neuroglycopenic symptoms:
    • Confusion
    • Drowsiness
    • Odd behavior
    • Speech difficulties
    • Incoordination 3
  • Additional symptoms:
    • Inability to concentrate
    • Weakness
    • Dizziness
    • Tiredness
    • Difficulty in speaking
    • Shivering
    • Drowsiness 4

Classification of Symptoms

Symptoms of hypoglycemia can be classified as adrenergic or neuroglycopenic 5.

  • Adrenergic symptoms are caused by the release of adrenaline in response to low blood glucose levels.
  • Neuroglycopenic symptoms are caused by the lack of glucose in the brain.

Variability of Symptoms

It's worth noting that the symptoms of hypoglycemia can vary from person to person, and may not always be specific to hypoglycemia 3, 5.

  • Some people may experience mild symptoms, while others may experience more severe symptoms.
  • The symptoms of hypoglycemia can also be affected by the frequency and severity of hypoglycemic episodes, as well as the individual's overall health and medical history 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Symptoms of hypoglycemia, thresholds for their occurrence, and hypoglycemia unawareness.

Endocrinology and metabolism clinics of North America, 1999

Research

[Causes, diagnosis, and treatment of hypoglycemia].

Medicina (Kaunas, Lithuania), 2006

Research

Hypoglycemia. Definition, clinical presentations, classification, and laboratory tests.

Endocrinology and metabolism clinics of North America, 1989

Research

Hypoglycemia in diabetes.

Diabetes care, 2003

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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