If you have hypoglycaemia, it is important to seek medical advice to ensure that any possible underlying cause of hypoglycaemia is investigated and treated as necessary.
Q. What is hypoglycaemia?
A. Hypoglycaemia (which literally means low sugar in the blood) occurs when your blood glucose falls below 4 mmol/l.
When we eat food, it is digested and broken down into various substances including glucose. The glucose passes into the blood stream, increasing the blood glucose level. As this level rises the body produces insulin (a hormone or chemical messenger) from the pancreas. Insulin helps glucose to enter the body's cells, where it is used for energy, and stores excess glucose in the muscles and liver. The action of insulin helps glucose to be used by the body and therefore lowers the amount of glucose in the blood.
As this level of glucose in the blood falls the body responds by releasing another hormone, glucagon. This works as the partner of insulin. It stops the production of further insulin and releases stored glucose back into the blood stream. With these two hormones working together the blood glucose always stays generally between 4 and 8 mmol/l.
Hypoglycaemia occurs when the balancing partnership between these two hormones has not worked as well as it should have.
Q. What are the symptoms of hypoglycaemia?
A. The symptoms of hypoglycaemia will vary from person to person.
Physical symptoms may come on very quickly. The most commonly described symptoms are sweating, palpitations (racing heart beat), shakiness, becoming pale, and tingling around the lips. They may start abruptly with no apparent cause and may be exacerbated by strenuous exercise.
Other symptoms can include anxiety or uneasiness, light-headedness, poor concentration or drowsiness.
In people with diabetes hypoglycaemia is caused by the medication that they take. Because this cannot be 'switched off' by glucagon, their symptoms may progress to a stage where they lose consciousness. As the medication wears off, they will recover from this.
In people without diabetes similar symptoms can be experienced, although it is unusual for hypoglycaemia to proceed so far, because the body's balancing mechanism will start acting more quickly. A very small number of people may get no obvious symptoms of hypoglycaemia, however, and may become unconscious, depending on the underlying cause.
Q. How is a diagnosis of hypoglycaemia established?
A. Blood glucose levels must be measured to establish a diagnosis of hypoglycaemia. Strict criteria for the diagnosis exist and slightly low blood glucose levels are not relevant to this diagnosis.
Obviously the best time to take the blood sample to measure low glucose levels is when the individual is experiencing the symptoms. As these are usually short lived, it can be very difficult for the doctor to take a sample at the right time. However, if there is a strong suspicion of hypoglycaemia in a patient, and it is impossible to take a blood sample during an episode of symptoms, there are investigations which can be performed to confirm the diagnosis. Referral by a GP to specialist for evaluation may be appropriate.
Q. What are the causes of hypoglycaemia?
A. Many individuals may experience some of the symptoms described above. Most will not have true hypoglycaemia. For example, anxiety, palpitations or poor concentration are frequently seen in people under stress. Those who have very busy routines may also find it hard to eat regular meals and this can play a part in producing these symptoms.
There are many different disorders that can lead to true hypoglycaemia.
Anyone experiencing symptoms of hypoglycaemia on a regular basis should discuss these with their doctor as they may indicate some other problem, which may need to be treated.
Long-term treatment
To avoid the symptoms of hypoglycaemia the best treatment is to prevent the fall in blood glucose levels between your meals. Today's busy lifestyles can often mean that meals are missed and individuals can go a long time between eating. Eating smaller meals and snacks more frequently helps many people prevent hypoglycaemia. The meals and snacks should include a balance of foods including good quantities of starchy foods like bread, potatoes, pasta and breakfast cereals and smaller amounts of fat and sugar. This keeps stores of glucose in your body topped up and can prevent them from falling too low. Cutting down on sugary and fatty foods can also help.
For more specific advice ask your doctor to refer you to a state registered dietitian.
Reviewed October 2011
Next review October 2012