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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 under 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 nervous alterations and tissue hypoperfusion, in which there is little amount of oxygen reaching the tissues, and of the intensity of physical activity and fatigue muscle, since the more intense the activity, the greater the need for oxygen and energy, which leads to greater production of lactate.
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 measurement is important to assess the general condition of the patient and check the response to treatment. Usually, the dosage is done in hospitalized patients who are suspected or 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.
This way, when performing the lactate measurement, it is possible to verify if the patient is responding to the treatment or if it is necessary to change the therapeutic plan and increase care according to the decrease or increase in lactate levels.
In sports, the lactate dosage makes it possible to determine the athlete's performance level and exercise intensity.In very intense or long-term physical activities, the amount of available oxygen is not always sufficient, and lactate production is necessary to maintain cell activity. Thus, measuring the amount of lactate after physical activity allows the physical educator to indicate a more adequate training plan 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 equal to or greater than 4.0 mmol/L 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 is 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 an increase in lactate production, a change in the supply of oxygen to the tissues or a deficiency in the elimination of this substance from the body, resulting in its accumulation in the blood. So, 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 the production of lactate;
- 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 system cells, resulting in an increase in lactate production in an attempt to maintain cellular activities and aid in the resolution of inflammation.Lactate dosage in this situation is widely used to monitor the patient's response and measure the risk of organ failure, being a prognostic indicator;
- Cardiogenic shock, in which there is a change in the blood supply to the heart and, consequently, oxygen;
- Hypovolemic shock, in which there is a large loss of fluid and blood, altering the distribution of blood to the tissues;
In addition, some studies have shown that increased lactate can occur in the case of liver and kidney problems, diabetes mellitus, drug and toxin intoxication and metabolic acidosis, for example. Thus, based on the assessment of lactate concentration, it is possible to diagnose diseases, monitor the patient's evolution and response to treatment, and predict the clinical outcome.