Low Blood Sugar

Low blood sugar is referred to as hypoglycaemia. It is the most common and most dangerous condition for many people with both type 1 and type 2 diabetes. This occurs when the blood glucose drops below the normal level.

Levels of blood glucose below 70 mg/dl are considered below normal according to the American Diabetes Association. This level, however, may be different for different individuals and this may sometimes depend on age or body mass of the individual.

For example, blood sugar of 90mg/dl is considered low for a baby or for an elderly person. Hypoglycaemia, when severe may lead to insulin shock, which can be life threatening if not promptly treated.

Reasons for hypoglycaemia or low blood sugar

Persons with diabetes are most at risk of hypoglycaemia and associated complications. Some of the common causes of low blood sugar among diabetics include:

  • Overdose of insulin
  • Skipping, omitting or delaying a meal
  • Excessive alcohol consumption along with skipping a meal
  • Wrong site of insulin injection that has led to faster absorption rates
  • Excessive exercise
  • Severe illness or injury that ups the requirement of insulin
  • Use of other hormones or medications that increase the action of the blood sugar lowering medications

Symptoms of low blood sugar

The brain utilizes glucose as the primary source of energy. With fall in blood sugar levels the brain is deprived of glucose and this may lead to weakness, fatigue and irritability initially and convulsions/seizures and unconsciousness if not corrected immediately.

The list of general symptoms of low blood sugar include:

  • Nervousness
  • Shakiness
  • Fatigue
  • Tiredness
  • Weakness
  • Personality change/irrational behavior
  • Weakness of limbs
  • Dizziness
  • Blurry vision
  • Poor coordination
  • Loss of sense of balance and falls
  • Nausea and sometimes vomiting
  • Sweating
  • Palpitations and rapid heart beats
  • Hunger
  • Light headedness
  • Drowsiness
  • Lack of concentration
  • Headache
  • Severe conditions lead to convulsions or seizures and even unconsciousness.

Symptoms vary from person to person and most diabetics are adept at recognizing their symptoms of hypoglycaemia.

Management of low blood sugar

It is a myth that only diabetics on insulin are at risk of hypoglycaemia. Those on oral medications are also at risk of this condition. Those with frequent attacks of hypoglycaemia may need a change in their treatment plan.

Usual immediate treatment includes a blood sugar check and one of the following treatments called emergency foods. It is usually 15gms of glucose equivalent or carbohydrate equivalent this may mean:

  • 3 or 4 glucose tablets
  • 4 ounces (half a cup) of any fruit juice
  • 4 ounces (half a cup) of a regular-not diet-soft drink
  • 1 tube of glucose gel
  • 8 ounces (a cup) of milk
  • 5 or 6 pieces of hard candy (not sugar free)
  • 1 tablespoon of sugar or honey

The next step is to recheck blood glucose in 15 minutes to make sure it is 70 mg/dL or above. If the level continues to be low the emergency foods need to be re-administered. If the next meal is an hour or more away, a snack should be eaten once the emergency foods have raised the blood glucose level to 70 mg/dL or above.

Prevention of low blood sugar

Low blood sugar episodes may be prevented by changing the therapy regimen or by adopting other practices. These include:

  • Taking meals on time
  • Not to skip meals or snacks
  • Checking blood sugars regularly
  • Adjust medications and exercise to maintain normal blood sugar control
  • Avoid excess alcohol especially along with skipping meals

Reviewed by April Cashin-Garbutt, BA Hons (Cantab)

Further Reading

Last Updated: Apr 22, 2019

Dr. Ananya Mandal

Written by

Dr. Ananya Mandal

Dr. Ananya Mandal is a doctor by profession, lecturer by vocation and a medical writer by passion. She specialized in Clinical Pharmacology after her bachelor's (MBBS). For her, health communication is not just writing complicated reviews for professionals but making medical knowledge understandable and available to the general public as well.


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  1. Eva Pereiradasilva Eva Pereiradasilva Brazil says:

    gente obrigada isso foi de extrema ajuda vc acabou de salva meu marido com estes sintomas ele tem diabete tipo 1 li com cuidado os sintomas dei uma colher de açucarde e
    Emergencia 15 minutos de pois ele voltou ao normal

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
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