Low blood sugar (hypo): recognise it and act right

A colleague is sweating, shaking, looks pale and is acting strangely. It can look like drunkenness, but it may also be low blood sugar: a hypo. Recognising it quickly and acting correctly makes a big difference. Here we follow the ERC Guidelines 2025 for First Aid.

When is blood sugar too low?

According to the ERC guidelines, blood sugar is low when it drops below 4.0 mmol/L (70 mg/dL). People with diabetes are especially at risk.

Recognising low blood sugar

Watch for these signs:

• sweating;
• shaking;
• looking pale;
• hunger;
• confusion;
• strange behaviour.

That strange behaviour can look like drunkenness, which is why a hypo is sometimes misjudged. In doubt? Assume it could be low blood sugar.

The person is awake and can swallow

Is the person awake and able to swallow safely? Give sugar:

• 15 to 20 grams of glucose, for example dextrose tablets;
• or 50 to 100 ml of fruit juice;
• or glucose gel.

Then wait 15 minutes. Still having symptoms? Repeat the same step. If a blood glucose meter is available, take a measurement.

The person is not responding (properly)

A strict rule applies here: never give anything by mouth to someone who is not responding or not responding properly. There is a risk of choking.

In that case:

1. Call 112.
2. Is the person breathing normally? Place them in the recovery position and keep monitoring their breathing.
3. Is the person not breathing normally? Start CPR and have someone fetch an AED.

Read more about those first minutes in CPR and AED: the first four minutes.

Tips for employers

A hypo can happen to anyone with diabetes. A few simple arrangements help:

• Know who has diabetes, if that person wants to share it. That remains a personal choice.
• Keep dextrose in your first aid supplies. Dextrose is not a medicine, so it can be included.
• Make sure your first aiders know the difference between someone who is awake and can swallow, and someone who is not responding properly.

What else belongs in your first aid kit? Read What should be in a first aid kit?.

Something to hold on to under stress

Under stress you quickly forget which step comes first. A clear action card on the wall sets out the order: recognise, give sugar or call 112, and keep monitoring.

Want your team trained in this? Request a quote.

Source: Resuscitation Council UK – summary of the ERC Guidelines 2025 First Aid