Fasting blood sugar: high, low, normal, dangerous?

Blood sugar corresponds to glucose level (sugar) contained in the blood. Sugar is an essential nutrient for the proper functioning of the body’s cells. Part of the glucose in the blood is transformed into glycogen which provides the body with energy. It is important to know the normal blood sugar level with an empty stomach. Below a certain blood sugar level, we speak ofhypoglycemiawhile above, it is more of a hyperglycemia. Diabetes can be detected by this analysis.

What causes blood sugar levels to vary?

In the body, the regulation of blood sugar is achieved through a permanent balance between different hormones. Insulin for example – a hormone produced by the pancreas – lowers blood sugar, while glucagon, adrenaline, growth hormone or cortisol make it increase. Diet, physical activity and stress also cause blood sugar levels to vary. If functioning properly, the pancreas produces insulin based on blood sugar levels.. After a meal high in carbohydrates, blood sugar levels rise and stimulate the release of insulin. This hormone attaches to the membranes of certain cells, thus promoting the entry of glucose into the cells and ensuring a drop in blood sugar levels. Monitoring your blood sugar is important because it helps you know if there is a problem with insulin production or insulin receptors. “This also makes it possible to determine if the patient has diabetes or a disorder of glucose regulation, especially since diabetes is a silent pathology. It is therefore useful to check your blood sugar, even in the absence of symptoms, since there is a higher risk of having diabetes (family history, overweight, the existence of other health problems such as high blood pressure). )“, specifies Dr Marc Popelier, specialist in diabetology at Pitié-Salpêtrière in Paris. The blood sugar level is prescribed by a doctor during a consultation or in hospital when the patient presents symptoms suggestive of a decrease in insulin secretion such as:

• the thirst
• tiredness
• a recurrent mycosis type infection
• weight loss

He can also prescribe this test if, on the contrary, he suspects an abnormal increase in insulin secretion (when the patient feels unwell, for example). This exam is also recommended for people with high risk factors (such as being overweight or with a family history of diabetes). Finally, such an examination – in particular the OGTT test – can also be prescribed during pregnancy, in order to detect possible gestational diabetes, a diabetes which generally disappears a few months after childbirth.

To test blood sugara person not diagnosed with diabetes, a blood test is taken on an empty stomach. “In the presence of symptoms, a urine test can be carried out“, specifies the specialist in diabetology. If the examination consists of a blood test, this is generally carried out at the bend of the elbow, after applying a tourniquet. If the doctor opts for a urine sample, a test strip is dipped in the urine and can detect the presence of glucose.

A person with diabetes can check her blood sugar level herself, using a portable device that allows her to take a drop of blood from her finger (we speak of capillary blood sugar or dextro). By capillarity, the blood gradually rises on a strip. “The results can be recorded and discussed with the caregiver or used immediately for an action (doing a physical activity for example)“, he adds. Finally, there are devices for people treated with insulin (several injections per day) that allow the glucose level in the tissues to be measured without having to prick the fingertip.

What is the normal fasting blood sugar level?

When fasting, so-called “normal” blood sugar levels must be understood between 0.70 and 1 gram of glucose per liter of blood. Up to two hours after a meal, blood sugar levels can rise to 1.4 g/L. Measuring blood sugar after a meal is not sufficient to confirm the diagnosis of diabetes. We speak of diabetes when this value exceeds 1.26g/L, fasting and with at least two blood sugar checks.

Table: what is the correct fasting blood sugar level?

Low blood sugar: levels, what causes?

Below 0.70 g/Lwe are talking abouthypoglycemia. that is, the blood sugar level is too low. “Eating a piece of sugar or something sweet helps raise blood sugar levels: on average, ingesting 15 g of sugar (3 pieces) helps raise blood sugar levels by 0.5g/L“, says Dr. Popelier. “Hypoglycemia manifests itself by symptoms such as pain, weakness, tremors which can lead to discomfort. These episodes are favored by a significant physical effort or a meal that is too low in carbohydrates“. On the other hand, if several tests indicate frequent hypoglycemia or associated with symptoms such as dizziness, tremors, difficulty concentrating, sudden headaches, it is necessary to carry out Additional tests in order to understand the causes, the circumstances of occurrence and to consider an appropriate treatment. To know, hypoglycemia is common in diabetic people treated with insulin (whose hypoglycemic treatment is not suitable) and in certain people who have had stomach surgery, or suffer from adrenal or hepatic diseases.

High fasting blood sugar: levels, what causes?

Above 1g/L (fasting or more than two hours after a meal), we then speak of a moderate hyperglycemia, that is, the blood sugar level is too high. Hyperglycemia can be manifested by frequent urge to urinate, intense thirst, severe dry mouth and tongue or a feeling of exaggerated fatigue. But sometimes, these symptoms go unnoticed, hence the importance of regular blood sugar monitoring in the event of risk factors (family history, excess weight, etc.). The causes of hyperglycemia are numerous:

• disruption of the pancreas and insulin secretion,
• the release of glucose by the liver when the latter has not had any nutritional intake for more than 8 hours,
• too much dehydration,
• excessive fever,
• taking certain medications (such as cortisone for example).

If after a second check with a value greater than 1 g/L, you still have hyperglycemia, you will need to carry out other blood sugar tests (generally a dosage of glycated hemoglobin, a more precise indicator when looking for or monitoring diabetes): hyperglycemia can reveal diabetes or glucose intolerancewhat is called pre-diabetes (non-diabetic hyperglycemia, but which must be monitored because it is often the common stage of transition to type 2 diabetes).

Diabetes A result greater than 1.26g/L of blood (fasting and if two controls are greater than this value) indicates diabetes, “a complex disease which certainly involves the pancreas, but also other organs such as the liver, muscles and intestines“. A person with diabetes must be taken care of (insulin injections or treatment with hypoglycemic drugs) and think about what could be implemented on a daily basis, particularly regarding diet or physical activity. Finally, in people diagnosed with diabetes, hyperglycemia can reflect an incorrect dosage or ineffectiveness of the treatment (insulin pump broken down, catheter malfunction, presence of ketone bodies in the urine) and will help to adjust the treatment.It is then useful for patients and caregivers to agree on the measures to take based on the results of the various checks.“, he concludes.

If it is impossible to combat the poor functioning of the pancreas or the insulin it secretes, a few health and dietary measures can help you reduce blood sugar levels:

• a weight loss (even 2 or 3 kg can be enough to improve the situation) if you are overweight,
• a healthy and balanced diet, “iThere are no foods to stigmatize, but the enemy is often excess calories. Fat is just as important to take into account as sugar.“, he explains.
• occasional alcohol consumption,
• stopping smoking,
• Regular sports practice helps improve blood sugar levels.

Thanks to Dr Marc Popelier, specialist in diabetology at Pitié-Salpêtrière (Paris).