Lactate is a product of glucose metabolism, that is, it is the result of the process of transforming glucose into energy for cells when there is not enough oxygen, a process called anaerobic glycolysis. However, even in aerobic conditions, in which there is oxygen, lactate is produced, but in smaller amounts.
Lactate is an important substance, as it is considered a signal for the Central Nervous System, a biomarker of nerve alterations and tissue hypoperfusion, in which there is little amount of oxygen reaching the tissues, and of intensity of physical activity and muscle fatigue, since how much the more intense the activity, the greater the need for oxygen and energy, which leads to greater lactate production.
When to take the lactate test
The lactate test is widely used in clinical practice in hospitalized patients and as an indicator of the intensity of physical activity and muscle fatigue. In hospitals, lactate dosage is important to assess the patient's general condition and verify the response to treatment. Normally the dosage is done in hospitalized patients who are suspected or have been diagnosed with sepsis or septic shock, which are situations characterized by lactate above 2 mmol / L in addition to decreased blood pressure, rapid breathing, decreased urine production and confusion mental.
Thus, when performing lactate dosing, it is possible to check whether the patient is responding to treatment or whether it is necessary to change the therapeutic plan and increase care according to the decrease or increase in lactate levels.
In sports, the dosage of lactate allows to determine the degree of performance of the athlete and the intensity of the exercise. In very intense or long-lasting physical activities, the amount of available oxygen is not always sufficient, requiring the production of lactate to maintain cell activity. Thus, measuring the amount of lactate after physical activity allows the physical educator to indicate a training plan more suitable for the athlete.
The lactate value is considered normal when it is less than or equal to 2 mmol / L. The higher the lactate concentration, the greater the severity of the disease. In the case of sepsis, for example, concentrations of 4.0 mmol / L or greater can be found, which indicates that treatment should be started as soon as possible to avoid complications.
To perform the lactate test, it is not necessary to fast, however it is recommended that the person be at rest, since physical activity can alter lactate levels and, thus, influence the test result.
What does high lactate mean
The increase in the concentration of circulating lactate, called hyperlactemia, can happen due to increased production of lactate, changes in the supply of oxygen to the tissues or deficiency in the elimination of this substance from the body, resulting in its accumulation in the blood. Thus, high lactate can happen due to:
- Sepsis and septic shock, in which, due to the production of toxins by microorganisms, there is a decrease in the amount of oxygen that reaches the tissues, with an increase in lactate production; Intense physical activity, because in some situations the amount of oxygen to perform the exercise is not enough, with an increase in lactate production; Muscle fatigue, due to large amounts of lactate accumulated in the muscle; Systemic inflammatory response syndrome (SIRS), as there is a change in blood flow and immune cells, resulting in increased lactate production in an attempt to maintain cellular activities and assist in the solution of inflammation. The lactate dosage in this situation is widely used to monitor the patient's response and measure the risk of organ failure, being an indicator of prognosis; Cardiogenic shock, in which there is a change in the blood supply to the heart and, consequently, oxygen; Hypovolemic shock, in which there is great loss of fluids and blood, changing the distribution of blood to the tissues;
In addition, some studies have shown that the increase in lactate can happen in the case of liver and kidney problems, diabetes mellitus, poisoning by drugs and toxins and metabolic acidosis, for example. Thus, from the assessment of lactate concentration, it is possible to make the diagnosis of diseases, monitor the evolution of the patient and the response to treatment and predict the clinical outcome.
