What is low blood sugar?

Low blood sugar occurs when blood glucose levels fall below 4mmol/l.  It is a daily concern for people with diabetes and, for many individuals, severe low blood sugar is a major obstacle to the achievement of normal blood glucose levels and the prevention of long-term complications.  Low blood sugar can be caused by:

  • taking too much insulin or oral diabetes tablets;

  • skipping meals, or delaying mealtimes;

  • not eating enough food;

  • undertaking physical exercise/exertion without adjusting intake of insulin/tablets/carbohydrates;

  • alcohol consumption;

  • hot weather;

  • stress; and

  • taking certain other medicines.


What does low blood sugar feel like?

People experience different symptoms associated with low blood sugar.  However, it is especially important to recognise your own warning signs.  Some common symptoms include, but are not limited to:

  • trembling;

  • sweating;

  • weakness;

  • difficulty concentrating;

  • palpitations, fast/pounding heart;

  • blurred/changed vision;

  • confusion, irritability;

  • anxiety, excitement;

  • hunger;

  • tiredness, drowsiness;

  • dizziness;

  • difficulty speaking;

  • headache;

  • nausea; and

  • tingling.


How should I treat a low blood sugar episode?

It's essential to stay calm and act promptly.  For most people, the major aspect in preventing low blood glucose levels is the low threshold they must have for dealing with such a situation.  In other words, know when you have low blood sugar and act immediately.

The following are guidelines only, as everybody's needs are different. Your GP or Diabetes Specialist Nurse will advise you on how to treat low blood glucose.  At the first signs of the onset of low blood sugar, you should take 10g–20g of fast acting carbohydrate and repeat again after 10 minutes, if necessary.  This should be followed by a snack of sustained release carbohydrate (e.g. a sandwich or milk and biscuits). 

Patients who remain in control of their diabetes with a minimum of low blood sugar events are more likely to achieve near normal blood glucose levels and avoid future chronic ill health, disability and premature mortality that can be associated with the disease.


How can I be prepared for the onset of low blood glucose?

Frequent self-monitoring of blood glucose should reduce the frequency of low blood sugar episodes.  It is important that meals are not skipped after taking insulin.  In addition, adjustments in diet must be made if exercise or physical exertion is planned, as this may cause a lowering of glucose.  An additional intake of food or a change in insulin dosage will be required. Carbohydrate/glucose should always be close to hand.

It's also important to share your knowledge with family, friends and work colleagues, so they know how to recognise the signs and how to help you.

What is diabetes?

What is low blood sugar?

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