What counts as low?
A glucose below 70 mg/dL (3.9 mmol/L) is considered low. Below 54 mg/dL is serious. Some people feel symptoms at higher levels if their sugars have been running high.
Symptoms
- Shaking, sweating and a pounding heart
- Hunger, anxiety or irritability
- Headache, blurred vision or difficulty concentrating
- In severe cases: confusion, seizures or loss of consciousness
Common causes in people with diabetes
- Insulin or sulfonylurea tablets, especially if the dose is too high
- Missed or delayed meals
- Unusual exercise, or alcohol
- Reduced kidney function, which makes some medicines last longer
Low sugar without diabetes is less common. Causes include alcohol, some medicines, liver or kidney disease, hormone deficiencies such as cortisol, and rarely an insulin-producing tumour.
What to do
If the person is awake and can swallow, give about 15 g of fast-acting sugar: glucose tablets, about 150 ml of fruit juice or a regular soft drink, or three teaspoons of sugar or honey. Recheck after 15 minutes and repeat if still below 70 mg/dL. Once it recovers, have a snack or meal.
If the person is drowsy, confused or unconscious, do not put food or drink in the mouth. Call emergency services (108) and use glucagon if it has been prescribed.
Preventing lows
- Do not skip meals when on insulin or sulfonylureas
- Check sugars before driving and before exercise
- Always carry fast-acting sugar
- Tell your doctor about any low; the dose may need changing
When to see a specialist
See a doctor if you have frequent lows, lows at night, lows with no warning symptoms, or a low sugar without having diabetes.
This guide is general information and is not a substitute for a consultation.