Low blood glucose can cause sweating, trembling, hunger, palpitations, dizziness, irritability, confusion or unusual behaviour. Some people have little warning.
Common causes
Skipped meals, excessive insulin or certain medicines, unusual exercise, alcohol, vomiting, changes in kidney function or continuing an old dose after weight loss can contribute.
Safe immediate response
If the person is awake and can swallow safely, follow the fast-acting carbohydrate plan taught by their clinician and recheck glucose. High-fat foods such as chocolate may act too slowly. If unconscious, having a seizure or unable to swallow, give nothing by mouth and seek emergency help.
For many adults, the familiar 15–15 approach uses approximately 15 grams of fast-acting carbohydrate followed by a glucose check after 15 minutes, with repetition if still low. Measured glucose tablets or a glucose drink may be suitable. Children and people with particular treatment needs require an individual plan; confirm the amount and response beforehand.
Prepare to prevent lows
Keep fast-acting glucose available at home and outside. Teach family members the warning signs and emergency response. People using insulin or a sulfonylurea should plan for delayed meals, fasting, travel, exercise and illness. Do not drive while symptomatic; ask whether checking before driving is appropriate.
Night sweating, nightmares or morning headache can sometimes suggest overnight lows, but do not change doses based on symptoms or a high morning value alone. Meter readings, CGM data, meal patterns and medicine timing help identify what is happening.
When review is needed
A severe episode, overnight lows, symptoms while driving or repeated readings below 70 mg/dL warrants treatment review. Bring records of glucose, meals and medicine timing. A clinician can revise targets or treatment and discuss an emergency rescue plan where appropriate.
See the diabetes clinic and appointment options.
Sources
This article is for health education and does not replace an individual medical consultation. Symptoms, test results, medicines, and treatment decisions should be discussed with a qualified clinician.
Seek urgent medical care for severe breathing difficulty, chest pain, confusion, fainting, uncontrolled bleeding, severe dehydration, or rapidly worsening symptoms.