Go to page content

Is recurring low blood sugar harmful?

Even just slightly lower blood sugar can cause a wide range of issues. Worrying about your blood sugar level dropping too low may also lead to high blood sugar.

Usually, the ability to function is still relatively normal when blood sugar level is 3.0–3.9 mmol/l. Even though it may cause low blood sugar symptoms, it is not immediately dangerous. Even just slightly lower blood sugar, especially if it drops below 3 mmol/l, can cause a wide range of issues:

  • Ability to perform tasks which require precision or concentration is impaired.

    • It may create dangerous situations in traffic.

  • The low blood sugar symptoms start to reduce and disappear if blood sugar is often or constantly low. In this case, the symptoms that warn of the low blood sugar only emerge at a lower blood sugar level, or they may be missing entirely.

  • Just slightly low blood sugar reduces the amount of sugar stored in the liver and increases the risk of a new low the following night or during exercise.

  • Low blood sugar causes a reactive increase in blood sugar as the liver releases its storages of sugar. This may lead to a blood sugar “roller coaster”.

  • Constantly eating to correct low blood sugar leads to weight gain.

Concern about blood sugar going too low is common and understandable, especially among people with insulin-treated diabetes and their close ones. If not addressed, these worries and the fear of low blood sugar can lead to excessively high blood sugar levels, as person may be afraid to keep their blood sugar at the target level. It is important to learn to anticipate situations where your blood sugar may drop too low and, on the other hand, identify the symptoms of hypoglycaemia and know what to do when it happens.

Updated 30.9.2023