The indicator that characterizes the concentration of sugar in the blood is called glycemia. It reflects the specific content of glucose in 1 liter of blood. At the same time, the actual amount of carbohydrate in the plasma can vary, which is characteristic of pathology, starvation or physical activity. According to the WHO norms established in 1999, the normal value of glycemia ranges from 3.3 mmol/l to 5.5 mmol/l. And at the moment, the upper value of 5.9 mmol/l is also accepted as the norm.
Changes in blood sugar concentration
The source of the increase in blood sugar concentration is carbohydrate food. As soon as glycemia rises, the body triggers a mechanism to reduce it. For this purpose, insulin is released, which increases the breakdown of glucose in tissues, or accelerates the process of storing glucose in adipose tissue. Counteracting insulin is glucagon, which increases the amount of blood sugar, increasing the synthesis of glucose in the liver.
Glucose itself is used up by cells for energy in oxidative phosphorylation reactions. A complex chain of chemical reactions leads to the accumulation of energy substrates that provide the needs of the body’s cells. The cells of the nervous system depend entirely on blood sugar concentrations. The brain can only process glucose, while muscle cells can also break down amino acids and fats.
For this reason, any disturbance in blood glucose levels will affect a person’s metabolism. In particular, a decrease in concentration below 2.8 mmol/L leads to hypoglycemic coma. Low blood glucose causes energy starvation of the brain, and the person may die in a coma.
The norm of hyperglycemia
Episodic increase in the concentration of sugar in the blood is not a disease, because the human body often experiences such an effect. It is associated with the ingestion of food: 0.5 hours after eating, the concentration of blood sugar slightly increases. Another hour and a half later, it should decrease. If the upper limit of the norm for a healthy person is 5.9 mmol / l, then 2 hours after the last meal, the concentration of glucose may be slightly higher. This is not yet pathology.
Diabetes mellitus and disturbance of fasting glycemia
A persistent and frequent rise in blood sugar concentration above normal goes by two names. To make a specific diagnosis, specialists resort to conducting a glucose tolerance test. If after 2 hours from the beginning of the test “sugar load” in the capillary blood of the patient contains more than 11.1 mmol / L glucose, then diabetes mellitus is diagnosed. If, however, the figure is 7.8 to 11.1 mmol/L, then glucose tolerance disorder will be listed as the diagnosis.
If you do not conduct a test with a “sugar load”, then the criterion for diabetes is the following pattern. If capillary blood drawn after a 12-hour fast contains between 5.5 and 6.1 mmol/L of glucose, a tolerance disorder is diagnosed. If the specific fasting glycemia value is higher than 6.1 mmol/L, diabetes mellitus is diagnosed. Values between 3.3 and 5.5 mmol/L are normal.