Hypoglycaemia: The Questions People Actually Ask
Hypoglycaemia: straight answers to the questions people actually ask, with the figures behind them.
Blood glucose falling too low, usually in people taking insulin or sulfonylureas.
Key takeaways
- Commonly defined as: below 4 mmol/L
- Early symptoms: shakiness, sweating, hunger, anxiety, palpitations
- Most useful single change: Carry fast-acting carbohydrate at all times.
- Commonest mistake: Driving with glucose below 5 mmol/L.
- See a doctor if any of the signs under "When to speak to a doctor" below apply to you.
What is Hypoglycaemia?
Blood glucose falling too low, usually in people taking insulin or sulfonylureas.
Why does it matter?
It can develop quickly, impairs judgement exactly when judgement is needed, and is dangerous while driving.
Commonly defined as for Hypoglycaemia?
Below 4 mmol/L.
Early symptoms for Hypoglycaemia?
Shakiness, sweating, hunger, anxiety, palpitations.
Immediate treatment for Hypoglycaemia?
15-20g of fast-acting carbohydrate.
Recheck after for Hypoglycaemia?
15 minutes, and repeat if still low.
What is the single most useful thing to do?
Carry fast-acting carbohydrate at all times.
What is the most common mistake?
Driving with glucose below 5 mmol/L.
When should I see a doctor?
Call 999 if someone with diabetes becomes unconscious, has a seizure, or cannot swallow safely — do not put anything in their mouth. Seek medical advice for repeated episodes, for loss of the early warning symptoms, or if episodes occur overnight. In the UK you must inform the DVLA if you have had severe hypoglycaemia requiring help from another person.
Where to go next
- Popular Beliefs About Hypoglycaemia, and What Is Actually Published
- Hypoglycaemia: A Beginner-Friendly Start
- Hypoglycaemia — the reference entry
- Diabetic Eye Screening: Sorting the Evidence From the Noise
- Carbohydrates and Blood Glucose: Sorting the Evidence From the Noise
When to speak to a doctor
Call 999 if someone with diabetes becomes unconscious, has a seizure, or cannot swallow safely — do not put anything in their mouth. Seek medical advice for repeated episodes, for loss of the early warning symptoms, or if episodes occur overnight. In the UK you must inform the DVLA if you have had severe hypoglycaemia requiring help from another person.
Where this comes from
- NICE — Type 2 diabetes in adults: management
- Diabetes UK — hypos
How this page was put together
Every figure, recommendation and warning above is taken from the guidance named in Where this comes from. Nothing on this page is inferred, summarised or generalised beyond what those bodies publish: where they give a number, it is their number, and where they are silent, so are we. Pages are rebuilt whenever the underlying record changes. Sign-off by a named clinician, where it has happened, is shown at the top of the page along with the date.
Medical disclaimer
This article is general information, not medical advice. It cannot account for your own history, medication or circumstances. Always speak to a GP, pharmacist or another qualified health professional before making changes that affect your treatment, and never delay seeking medical advice because of something you have read here. In an emergency, call 999.
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