PATIENT EDUCATION
Hypoglycaemia (Low Blood Glucose)
Hypoglycaemia is most common in people using insulin or certain glucose-lowering medicines. Symptoms can develop quickly and should be recognised early.
Select a topic below to view more information.
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Shaking, Sweating or Sudden Hunger
What you'll notice or feel
- Shakiness, sweating or palpitations.
- Sudden hunger, tingling or anxiety.
- Feeling weak, light-headed or irritable.
- Symptoms may improve quickly after glucose is taken.
Common causes
- Insulin or medicines that increase insulin release.
- A delayed or missed meal.
- More physical activity than usual.
- Alcohol, especially without enough food.
What it could be
- Mild to moderate hypoglycaemia.
- Another cause if glucose is normal during symptoms.
Initial self-care
- If you can safely swallow, treat according to your diabetes team’s low-glucose plan using fast-acting carbohydrate.
- Recheck glucose after treatment as advised.
- Follow with longer-acting carbohydrate if appropriate for your plan.
- Identify what triggered the episode.
When to see a doctor urgently
- Confusion, seizure, loss of consciousness or inability to swallow safely.
- Do not give food or drink by mouth to an unconscious person; use emergency glucagon if available and trained, and seek emergency help.
When to see a doctor
- Low glucose is happening repeatedly.
- You are having episodes without an obvious trigger.
- You need help adjusting insulin around meals or activity.
Night-time Low Glucose
What you'll notice or feel
- Waking sweaty, shaky or with palpitations.
- Nightmares or restless sleep.
- Morning headache or unusual fatigue.
- CGM alarms or low readings overnight.
Common causes
- Evening insulin dose or timing.
- Late exercise or alcohol.
- Insufficient evening carbohydrate for the treatment plan.
- Changes in kidney function or insulin sensitivity.
What it could be
- Nocturnal hypoglycaemia.
- CGM compression artefact or a non-glucose cause if meter confirmation is normal.
Initial self-care
- Confirm unexpected CGM lows with a meter when practical and safe.
- Review evening meals, exercise and alcohol patterns.
- Do not routinely overeat at bedtime without understanding the cause.
- Discuss recurrent overnight lows with the diabetes team.
When to see a doctor urgently
- Severe confusion, seizure or unresponsiveness.
- A person who cannot be safely awakened after suspected hypoglycaemia needs emergency care.
When to see a doctor
- Night-time lows recur.
- You are afraid to sleep because of hypoglycaemia.
- You have had a severe episode overnight.
Low Glucose During or After Exercise
What you'll notice or feel
- Shakiness, weakness or dizziness during activity.
- A glucose fall several hours after exercise.
- Unexpected low readings after unusually prolonged activity.
- Reduced exercise confidence because of previous lows.
Common causes
- Muscles use more glucose during and after activity.
- Insulin on board may be too high for the activity level.
- Insufficient carbohydrate before prolonged exercise.
What it could be
- Exercise-related hypoglycaemia.
- A need to individualise insulin, carbohydrate and activity planning.
Initial self-care
- Carry fast-acting glucose during exercise if you are at risk.
- Check glucose before, during or after activity according to your plan.
- Avoid exercising alone if you have a history of severe lows.
- Discuss insulin adjustment for planned exercise.
When to see a doctor urgently
- Severe confusion, seizure or collapse during exercise.
When to see a doctor
- Exercise repeatedly causes lows.
- You are avoiding beneficial activity because of fear of hypoglycaemia.
- You need an individual plan for sport or endurance exercise.
Medication or Meal Mismatch
What you'll notice or feel
- Low glucose after taking insulin but eating less than expected.
- Lows when meals are delayed.
- Lows after dose changes or weight loss.
- Episodes following vomiting or reduced appetite.
Common causes
- Insulin or sulfonylurea dose exceeds current needs.
- Meal timing has changed.
- Kidney or liver function has changed.
- Weight loss can reduce medicine requirements.
What it could be
- Treatment-related hypoglycaemia requiring medication review.
- Illness increasing the risk of both high and low glucose.
Initial self-care
- Do not repeatedly “feed” frequent lows without arranging medication review.
- Keep a log linking low readings with medicines and meals.
- Use sick-day guidance if you have been given one.
- Seek advice before fasting.
When to see a doctor urgently
- Persistent vomiting with diabetes.
- Repeated lows despite treatment.
- Loss of consciousness or seizure.
When to see a doctor
- Any recurrent medication-related low glucose.
- You have recently lost weight or kidney function has changed.
- You are planning religious fasting or major dietary change.
Hypoglycaemia Unawareness or Severe Episodes
What you'll notice or feel
- Little or no warning before glucose becomes very low.
- Others notice confusion before you do.
- A history of needing another person’s help.
- Severe episodes during sleep or while driving.
Common causes
- Repeated hypoglycaemia can blunt warning symptoms.
- Long duration of diabetes or autonomic neuropathy.
- Very tight glucose targets in some individuals.
What it could be
- Impaired awareness of hypoglycaemia, which substantially increases risk.
- A treatment plan that needs urgent re-evaluation.
Initial self-care
- Avoid driving until the issue is reviewed and local driving-safety rules are met.
- Carry glucose and medical identification.
- Ensure family members know how to use glucagon if prescribed.
- CGM with alerts may be helpful for some patients.
When to see a doctor urgently
- Any seizure, unconsciousness or episode needing external assistance is severe hypoglycaemia and needs urgent management.
When to see a doctor
- Arrange prompt specialist review after any severe episode.
- Warning symptoms are becoming less reliable.
- Hypoglycaemia is affecting work, driving or sleep.
YOUR CONSULTATION
What to Expect at Your Visit
- Review of glucose records, CGM downloads, insulin/medicine doses, meal timing and recent activity.
- Discussion of alcohol, fasting, weight change and kidney function where relevant.
- Assessment of whether warning symptoms are intact.
- Education on treatment of low glucose and use of glucagon when appropriate.
- Medication or insulin adjustment aims to reduce hypoglycaemia without causing excessive hyperglycaemia.
- A personalised prevention plan may include CGM alerts, exercise strategies and sick-day or fasting guidance.
* IMPORTANT: A Note Before You Go
For many people with diabetes, a glucose below 70 mg/dL (3.9 mmol/L) is treated as low, but individual targets and action plans can differ. Severe symptoms matter more than the number alone.
This page provides general educational information and cannot replace an individual medical assessment. If symptoms are persistent, worsening or concerning, arrange appropriate medical review.
NEED AN ASSESSMENT?
Arrange an Endocrinology Consultation
For non-emergency assessment or follow-up, appointments are booked through the hospital’s central appointment desk on 0422 432 4433. For severe or rapidly worsening symptoms, seek urgent medical care rather than waiting for a routine appointment.