Written by Ben Bunting: BA(Hons), PGCert. Sport & Exercise Nutrition. British Army Physical Training Instructor.  

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It's important to know your lactate threshold. When it comes to athletic performance, a person's lactate level can predict a person's ability to sustain an activity. 

Lactate Explained

Lactate is produced in the human body when food is turned into energy. It is also found in red blood cells. A high level of lactate can cause metabolic acidosis, which is an unhealthy condition that results from the accumulation of lactic acid.

The production of lactic acid can be triggered by an acid-base imbalance, which can be caused by a number of different conditions.

Fortunately, a lactate test can be used to diagnose sepsis, delirium, and uncontrolled diabetes. Nevertheless, it is important to understand that it does not always indicate a serious medical problem.

Production

Lactate can be produced by a number of different bacteria. Escherichia is a commonly found microorganism that is capable of producing lactate and acetate.

However, there are also phylotypes of Bacteroides that have a weak capacity for acid tolerance.

In addition, Streptococcus phylotypes are known to accumulate lactate. These phylotypes are known to be correlated with the presence of acetate and propionate.

Although most of the research on lactate has focused on the production of lactic acid, the impact of lactate on clinical outcomes remains speculative.

Studies that examined the effects of d-lactate or l-lactate on clinical outcomes have been done in animal studies, which have shown that the early administration of d-lactate or l-lactate is associated with a higher risk of mortality. As a result, d-lactate should be avoided in trauma or other critical situations.

Resuscitation

Lactate is a key component of resuscitation solutions. Originally introduced in 1882, Ringer's lactate solution is now used worldwide for the resuscitation of critically ill patients.

This lactate is added to fluid in equal amounts. After trauma, it is often used as a first line of defense for patient resuscitation.

Although lactate is not the only factor that can explain the relationship between blood lactate and mortality, it is one of the most important. During large intravenous fluid resuscitation, SIDe can increase.

Consequently, a SIG-lactate relationship may be stronger than an arterial lactate-lactate relationship. Moreover, combining lactate with SIG can reduce the prognostic significance of the SIG-lactate relationship.

Ultimately, lactate levels must be considered in any type of acid-base disturbance approach.

What Does a High Lactate Level Mean?

In critical care, blood lactate levels are commonly measured in order to assess the status of a patient. These measurements serve as indirect indicators for the status of the patient's organs and metabolism.

A higher lactate level may indicate a more severe illness than a lower one.

However, it is important to note that lactate levels are not always associated with a negative outcome. They can also be useful in monitoring the patient's response to treatment.

Energy

Lactate is produced when a cell turns glucose into energy. It can also be found in the brain and muscles.

When these tissues are unable to meet the demands of the body for oxygen, the cells will produce excess lactate. The accumulation of lactic acid will cause metabolic acidosis.

Elevated levels of lactate are associated with poorer outcomes in acutely unwell adults and neonates.

The reasons for the association are not clear, but may be related to congenital metabolic disorders, congenital hypoxemia, and inborn errors of metabolism.

Observational studies have found that hyperlactatemia is not associated with high SOFA scores, and that the presence of elevated lactate levels is not necessarily indicative of an abnormal microcirculation.

Studies of serial blood lactate levels, however, suggest that the failure to normalize lactate levels may have a prognostic value.

Monitoring of blood lactate is becoming increasingly popular in critically ill patients. Specifically, lactate measurements are being used as an indicator of tissue hypoxia.

This is a sign of a more advanced disease that affects the body's ability to meet its oxygen demands.

What Causes a High Lactate Level in the Blood?

There are different factors that can cause an elevated lactate level in the blood. 

Sepsis

Sepsis is one of the most common causes of a high lactate level in the blood. Lactate levels are increased in sepsis because the body has overreacted to an infection.

In this disease, the cells become hypoxic, so they turn to anaerobic glycolysis to produce energy. It is a serious illness, so patients should be treated quickly.

Pleural effusion

Another condition that can cause an elevated lactate level in a patient is pleural effusion. Pleural effusions are caused by a collection of fluid around the lung, which can cause a rise in the blood lactate concentration.

This can occur in patients with a number of different conditions.

Other causes of an elevated lactate level in the blood are respiratory failure, pulmonary edema, and cardiac arrest. Seizures also can increase the amount of lactate in the blood.

A lack of thiamine can also lead to lactic acidosis. Alcohol can also affect the body's ability to process thiamine.

Severe bacterial infections can also lead to a high blood lactate level. Fortunately, many cases of sepsis can be successfully treated. However, it is still important to identify the cause of the high level.

One study found that serial blood lactate levels were predictive of organ failure in septic shock. Patients with serial lactate levels that decreased over time had better outcomes.

An increasing emphasis is being placed on monitoring the blood lactate level. The use of point-of-care analyzers, such as blood gas analyzers, has made the measurement easier.

Using these monitors allows health care providers to accurately monitor the lactate level, which can tell them more about the patient's condition and response to treatment.

What is a Critical Lactate Level?

Blood lactate has become an important part of the assessment of critical illness and disease. It has been shown to be an effective marker of short-term patient morbidity, prognosis and mortality.

In addition, it has been found to discriminate patients with less morbidity from those with greater morbidity. Blood lactate levels have also been used in a variety of surgical interventions.

Lactate is produced in various processes in the body. Some examples are in the brain, glial cells and neurons.

When it is present in excess, it is known as hyperlactatemia. However, the degree of lactate can vary greatly. Therefore, the interpretation of increased blood lactate levels in sepsis can be difficult.

Lactate and acidosis are associated with high mortality in septic shock. Lactate levels can be measured in plasma or blood.

As a result, it has been important to develop guidelines for the measurement of lactate in these conditions.

A landmark human study showed that a rise in lactate values was associated with a lower survival rate. The study involved the use of a rapid lactate analyzer in critical care.

Goal-oriented hemodynamic therapy is also associated with lower mortality. The authors of the study showed that patients with goal-oriented hemodynamic therapy had normal blood lactate levels.

Although these findings are encouraging, they cannot predict whether a patient will require oxygen supplies in the future.

An increase in lactate levels can be attributed to infection or pleural effusions. Other causes include chronic liver disease, thiamine deficiency, alcohol consumption, malignancy and tumors.

It is said that critical levels of lactate are 4 mmol/L or higher (Foucher and Tubben).

Lactate Versus Lactate Acid

Lactate and lactic acid are two terms that have been used interchangeably in athletic settings, especially in relation to muscle soreness and fatigue.

While both acids are hydroxyls (alpha-hydroxy acids) and have a positive charge, they are distinct. Both are produced in the body and are important in energy production, metabolism, and the prevention of injury.

Lactate acid is a natural product of glycolysis. It plays a major role in ischemic tissue injury, wound healing, and memory formation.

It is a key energy substrate for skeletal muscle fibers. However, excess lactate can lead to lactic acidosis, which can have serious hemodynamic consequences.

Lactate is produced in a number of locations in the body, most notably in muscles. The rate-limiting enzyme is phosphofructokinase.

When phosphofructokinase is activated, ATP levels fall, which stimulates the AMP-activated protein kinase. This in turn produces a stimulus to release catecholamines. These include dopamine, norepinephrine, and epinephrine.

Lactate is the body's primary energy substrate. During intense exercise, it is produced in large amounts. During light-to-moderate activity, it is removed quickly from the bloodstream.

Lactate is a metabolic fuel that the body uses to help in the process of transforming food into energy. In the process, it is also used as a precursor for pyruvate, a metabolite that is important in aerobic energy production.

The body's most significant organs for elimination of lactate are the liver and kidneys.

Up to 70 percent of lactate is eliminated through these two processes. Some studies have found that excess lactate can disrupt metabolic pathways. This can lead to heart failure, cancer, and other health problems.

Lactate Threshold and VO2 Max

Lactate threshold is an important factor in endurance training and races. It refers to the point at which the accumulation of lactic acid in the blood exceeds the ability of the body to remove it.

The lactate threshold can be increased or decreased by training, and is used to determine the intensity of endurance workouts.

When performing a lactate threshold test, blood is drawn at several stages of the exercise. These include an easy or moderate pace, a moderate to heavy intensity, and a vigorous intensity. At the end of each stage, the blood is analyzed.

Many athletes and coaches use the lactate threshold as a way to estimate the intensity of an upcoming workout. Lactate threshold is also used to gauge fitness improvements.

Athletes may try to increase their lactate threshold by doing high intensity interval training. This method often involves 3-5 minute intervals at 95-100% of their maximum heart rate. Training at these intervals should make up 10-15% of their training volume.

In addition to reducing the risk of overtraining, lactate threshold training will also improve your overall aerobic efficiency. By developing a faster threshold, you will be able to tolerate higher intensities for longer periods of time.

For runners, the lactate threshold is a critical element of endurance training. Using technology such as a Stryd footpod, athletes can increase their power.

An effective lactate threshold workout is one that develops the mitochondrial density, capillarization, and fatigue resistance of muscle fibers. It also trains the muscle cells to better utilize the lactic acid produced.

Lactate threshold is the point where lactate accumulates faster than it can be eliminated. This is an indicator of the intensity of your exercise. It also gives a good predictor of your fitness level.

There are different ways to test your lactate threshold. One way is to run at a pace where you can maintain your speed for 30 minutes. You will have to stop halfway to take a blood sample.

Another method is to measure your heart rate at intervals over a three-minute period. Your average heart rate will give you an accurate indication of your lactate threshold.

The lactate threshold is an important performance metric for athletes. A higher threshold will allow you to work at higher intensities. The body has several systems that use lactate for energy. When lactate levels are high, you will experience a burning sensation.

Lactate threshold training can help you develop the endurance of your muscle fibers and improve your ability to metabolize lactate.

Training increases your muscle fiber density and capillarization, which is a key factor in increasing your endurance. Performing high-intensity interval training and strength training are two of the most effective ways to boost your lactate threshold.

VO2 max (or aerobic capacity) is a broader term that encompasses the maximum amount of oxygen you can breathe while doing physical activity. It varies depending on the type of physical activity you are performing.

Whereas the lactate threshold is where the athlete cannot dispearse as much lactate that's being produced.

Blood lactate tests predict performance

Endurance athletes use blood lactate tests to measure their lactate threshold. Lactate is a byproduct of anaerobic metabolism.

Its concentration increases with exercise intensity, but it is not harmful. In fact, it may help conserve force production. If an athlete crosses the lactate threshold, they must stop exercising.

Typically, blood lactate is between 1-2 mmol/L when at rest, but it increases quickly at high levels of exertion. During a prolonged effort, blood lactate can reach 20 mmol/L.

Blood lactate can be measured using blood draws at different stages of exertion. Some studies have shown a correlation between lactate threshold and performance.

However, the relationship between lactate threshold and time-trial performance is not entirely clear.

The correlation between the heart rate and lactate threshold is not always accurate during races. This is because the body's cardiovascular system has an increased rate of response during races.

Some reports suggest that ventilation-based indexes are better predictors of performance than blood-based indexes. This is because the ventilation-based indexes carry at higher power outputs than the direct blood-based indexes.

Another possible explanation for the disparity in results is that the time it takes for a muscle to release and be ventilated is longer during races. Therefore, the difference in heart rate at lactate threshold may be due to the increased adrenaline levels.

An indirect method of determining the lactate threshold used pulmonary gas exchange data. This method was applied to the 12-cyclists involved in a 1-h time trial in both hot and cool environments.

Although there were not significant differences between the methods, the results show that the "Ve/Vo2" method is a poor choice for events lasting less than an hour.

Clearing lactate from the blood

The process of clearing lactate from the blood is an intricate affair, which involves enzymes and transporters.

The rate at which lactate is cleared is influenced by factors such as the type of muscle fiber, the size of the muscle cell, and the degree of oxidation. Lactate must be metabolized before it can be used as a fuel. Its removal is accelerated by light activity and training.

There is no clear cut definition of the optimal number of seconds required to transport lactate from the limbs to the brain, though it is thought that the minimum is about a minute.

This makes lactate an important energy source for neurons. A small percentage of the lactate is exported to the blood.

During intense exercise, blood lactate levels can be several times higher than at rest. Similarly, in individuals with type 2 diabetes, blood lactate levels can be a few times higher than healthy controls.

A well-trained athlete should be able to clear lactate from the blood without resorting to oxygen toxicity.

Some studies show that aerobically fit individuals have higher levels of lactate clearance than less fit people.

Similarly, studies have found that training at the lactate threshold (i.e., the blood lactate concentration of the participant at the end of an endurance bout) can boost the rate of lactate removal by several mmol per minute.

Effects of continuous aerobic training on lactate threshold

Lactate threshold is a physiological parameter used to measure the maximum effort an athlete can endure. It is also a key indicator of cardiorespiratory fitness.

It is an important training goal for many endurance athletes. Increasing your lactate threshold is a good way to improve cardiovascular endurance and reduce body weight.

In addition, it can increase caloric expenditure and enhance weight loss. However, there is still some disagreement on the precise meaning of lactate threshold. Fortunately, there are guidelines that can be used to generate workouts.

The most common method of determining lactate threshold is blood lactate testing. Lactate concentration in the blood is measured with a finger stick. Often, this test is accompanied by heart rate. This test can also be done on a stationary bike.

A race is a good time to conduct a lactate threshold test. Typically, the 40-minute mark of a race will see a higher level of blood lactate concentration. If the level is too high, the athlete must stop exercising and allow the body to recover.

To test for lactate threshold, you will need a heart rate monitor and a timer. You can use a 30-minute time trial or a five- to 10-k field test.

While a 30-minute time trial may be a suitable test for experienced athletes, it can be hard on the body.

Similarly, a field test may not be appropriate for an unprepared athlete. Ideally, you should be in optimum physical shape before conducting a lactate threshold test.

The goal of lactate threshold training is to train the muscles to contract quickly and forcefully. This helps the body to clear lactic acid and improves mitochondrial respiration.

Conclusion

Lactate Threshold is one of the key performance indicators for athletes. It is commonly used in endurance sports.

Endurance training involves repeated efforts, resulting in a higher lactate concentration in the blood. When the concentration reaches a certain point, an athlete is no longer able to continue exercising.

There are different ways to measure lactate threshold. First, athletes can test their heart rate at a specific time.

For example, a 30 minute time trial. They can also record their heart rate at 10, 20, and 30 minutes. The result is a percentage of their maximum heart rate. This percentage can be used to adjust the heart rate-based training zones.

Another way to calculate lactate threshold is by performing a graded exercise test. In this test, athletes have to perform a series of runs at different intensity levels. As the intensity increases, the tester increases resistance on the trainer.

During these tests, the pace is increased every 3-5 minutes. The tester increases the resistance by 20 watts on the trainer each time. Ideally, the tests will last a full 30 minutes. Athletes need to run below their lactate threshold for the entire test.

Typically, the more experienced athlete may find their lactate threshold between 70 to 80 percent of their VO2max. However, a recreational athlete may fid their lactate threshold much sooner which could be around 50 to 60 percent of their VO2max.