Hypoglycaemia: recognising and managing low blood sugar

Hypoglycaemia is a low blood sugar episode that can affect thinking, movement and consciousness.

It is most often associated with glucose-lowering treatment for diabetes, although other medical causes are possible. Symptoms can appear quickly and may become more serious if the brain has too little glucose. Knowing your personal warning signs and a plan for prompt treatment can make episodes easier to manage.

Early signs can include tremor, sweating, hunger, dizziness, palpitations, irritability, blurred vision, nausea or weakness. With a more severe episode, speech may become slurred, coordination can worsen, and a person may have a seizure or lose consciousness. Hypoglycaemia commonly presents with dizziness, whereas dizziness has many possible causes.

A mismatch between diabetes medicine, food intake and activity is a frequent trigger. Missing or delaying a meal, drinking alcohol without food, unexpected exercise, illness or a dosing error can contribute. In people without diabetes, a clinician may consider medicines, hormone conditions, liver disease or other causes.

Symptoms usually improve after blood glucose is restored, but repeat episodes deserve review because the trigger may persist. Awareness can be reduced after frequent lows, leaving fewer early warning signs. Keep a note of timing, meals, activity, medicines and glucose readings when available.

Using insulin or medicines that stimulate insulin release can increase risk. Skipped meals, changes in daily routine, prolonged activity, alcohol, kidney problems and recent changes to diabetes treatment may also be relevant. Risk is higher when a person cannot recognise or respond to their usual symptoms.

A clinician combines the symptom story with a glucose measurement during or close to an episode when possible. They may review glucose-monitoring records, meal patterns, activity and medicines. Further blood tests are sometimes needed when episodes occur without an obvious diabetes-treatment trigger.

If the person is awake and can swallow, use their personal hypoglycaemia plan, often with a fast-acting glucose source followed by longer-acting food if the next meal is not soon. Recheck glucose according to the plan. Do not give food or drink to someone unconscious, having a seizure or unable to swallow; seek emergency help instead. A clinician may adjust diabetes treatment after recurrent episodes.

Carry a suitable fast-acting glucose option and tell close contacts how to recognise an episode. Wear or carry diabetes information if you use glucose-lowering medicine. Discuss driving, fasting, shift work and exercise plans with your diabetes team so precautions fit your routine.

Severe hypoglycaemia can lead to injury, seizure, loss of consciousness or dangerous situations such as a driving incident. Repeated lows can cause anxiety around food or activity and may reduce confidence in glucose management. Contact your care team after a severe episode.

Match meals and snacks to the plan agreed for your treatment, and plan extra carbohydrate or medication adjustments around activity when advised. Avoid changing prescribed doses independently. Review any episode that happens overnight, during exercise or without a clear trigger.

A GP or diabetes clinician can review repeated episodes and arrange further assessment. Bring your meter or sensor information, medication list and a record of recent episodes. Diabetes education can help turn these details into a practical daily plan.