Lactate threshold
Lactate threshold refers to the specific point during intense exercise at which the body begins to produce more lactate, or lactic acid, than it can effectively break down. This phenomenon occurs primarily when the body is unable to intake sufficient oxygen to sustain aerobic respiration, leading to anaerobic respiration, which generates lactate as a byproduct. As exercise intensity increases, so does lactate production, eventually resulting in symptoms such as muscle soreness and fatigue when the threshold is surpassed. Factors influencing a person’s lactate threshold include age, weight, body chemistry, and certain health conditions.
For athletes, understanding and training around their lactate threshold is critical; exercising just below this level can enhance performance by optimizing oxygen utilization and reducing the risk of discomfort from lactic acidosis. Athletes often engage in training techniques such as interval workouts to help increase their lactate threshold, enabling them to maintain higher intensity levels without experiencing the adverse effects of lactate buildup. Overall, knowledge of lactate threshold can help individuals optimize their training regimens and improve their athletic performance.
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Lactate threshold
Lactate threshold is the point at which the human body begins to make more lactate, or lactic acid, than it can simultaneously break down. The body creates lactate mainly during intense exercise, when the body requires large amounts of oxygen. Lactate can build up in the body and cause a number of different side effects, including burning muscles. Understanding the lactate threshold is important for athletes. Athletes who exercise just below their lactate thresholds can avoid the sore muscles that are common when lactic acid builds up. Exercising just below this level can also help athletes’ bodies take in more oxygen. A person’s lactate threshold depends on more than just exercise. Age, weight, body chemistry, and other factors affect a person’s lactate threshold. Furthermore, people with certain health conditions will have different lactate thresholds.
Background
Intense exercise can be very beneficial for the human body as it increases the heart rate and the amount of oxygen in the blood. This increased oxygen and increased body temperature can also cause a number of different chemical reactions in the body. The chemical reactions that take place in the body are affected by numerous variables. For example, a person’s age, size, sex, and blood type can all affect chemical reactions in the body.
Some chemical changes take place in people’s blood. When people exercise, the body needs to find ways to get energy quickly. The human body completes two functions to produce energy: aerobic and anaerobic respiration. To gain energy through aerobic respiration, the body breaks down glucose. This process requires oxygen. However, when a person is exercising at a high intensity, the body does not bring in enough oxygen to get all its energy from aerobic respiration. The body can also get energy through anaerobic respiration. This process creates energy and does not require oxygen.
When the body does not have enough oxygen, one of the waste products of anaerobic respiration is lactate, or lactic acid. Although anaerobic respiration is useful because it gives the body energy during intense workouts, the lactic acid can build up in the body, causing negative side effects. Once a person reaches the point in exercise where the body no longer has enough oxygen to break down the lactic acid and the lactic acid begins to build up, that person has reached the lactate threshold.
Overview
As people increase the intensity of their workouts, their bodies’ output of lactic acid also increases. When the body is ridding the body of lactic acid faster than it produces the acid, the body has not met the lactic threshold. A person’s lactate threshold is the point when lactate begins to build up in the body, causing lactic acidosis. Lactic acidosis occurs when people surpass the lactate threshold and have lactate in their system. Lactic acidosis can cause side effects for some people. For example, some people experience stomach-ache, nausea, and rapid breathing. Since lactic acid is acidic, it can cause a burning sensation in the muscles and can make muscles sore for days. The effects of lactic acidosis are generally temporary and will usually go away after a period of rest, though the symptoms can be unpleasant when a person experiences them. If, however, the symptoms persist, the person should see a medical professional.
When a person feels the symptoms of lactic acidosis, that person should begin to decelerate their exercise, though it is not generally recommended to stop intense exercise abruptly. Instead, a person can begin to slow the physical activity and eventually stop the exercise altogether. People who experience lactic acidosis should rest and give their bodies time to recuperate before exercising again. People who experience lactic acidosis should also drink plenty of water. Although intense exercise is among the most common causes of the body reaching the lactate threshold, it is not the only cause. Some medical disorders, such as cancer, seizures, shock, and sepsis, can also cause lactic acidosis.
Medical professionals and scientists can determine the lactate threshold through medical testing. To test a person’s lactate threshold, a researcher will have the person perform vigorous physical activity. Then, the research will collect blood samples to measure the amount of lactate in the blood. When the body begin to build up lactate, the researchers know a person has exceeded the lactate threshold. Researchers measure lactate threshold to understand more about intense exercise and body function. They also measure the lactate threshold to help individual athletes understand their personal lactate thresholds. Athletes who know their lactate thresholds can measure the intensity of a workout and understand what level of intensity is as high as it can be without passing the threshold. That means the athlete can work out as much as possible without getting the buildup of lactate in the muscles that causes discomfort.
Athletes are interested in lactate threshold. This is because the lactate threshold can indicate the ideal level of exercise intensity. If athletes exercised at lower than their lactate threshold, they would not be working as hard they could; however, if they worked at higher than their lactate threshold, they would experience lactic acidosis, which would hurt their performance in the end. Athletes who train just at their lactate threshold can actually increase their lactate threshold. When athletes work out, they increase their bodies’ ability to take in oxygen. As a person’s body takes in more oxygen, the body can rid itself of more lactic acid. For this and other reasons, most athletes have the goal of increasing the amount of oxygen their bodies can bring in.
Some athletes use interval training to increase their lactate threshold. In interval training, a person performs intervals of extremely intense physical exercise and intervals of much less intense exercise. If athletes feel that the intensity at which they are excising is too easy, they might be tempted to increase the intensity; however, their bodies will begin to produce excess lactate if they increase the intensity past the lactate threshold. Instead, athletes can increase the duration of their workouts so they can fully exhaust themselves without ever producing an overabundance of lactate and experience the negative side effects that lactate buildup can cause.
Bibliography
Blahd, William. “Lactic Acidosis and Exercise: What You Need to Know.” WebMD, 14 Jul. 2017. https://www.webmd.com/fitness-exercise/guide/exercise-and-lactic-acidosis#1. Accessed 11 June 2019.
Blessing, Jill. “The Chemical Reaction That Takes Place in the Body after Exercise.” Live Strong, https://www.livestrong.com/article/375841-the-chemical-reaction-that-takes-place-in-the-body-after-exercise/. Accessed 11 June 2019.
Ghosh, Asok Kumar. “Anaerobic Threshold: Its Concept and Role in Endurance Sport.” US National Library of Medicine, 2004, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3438148/. Accessed 11 June 2019.
Hyman, Lindsay. “The Performance Benefits of Lactate Threshold Testing and Training.” CTS, https://trainright.com/the-performance-benefits-of-lactate-threshold-testing-and-training/. Accessed 11 June 2019.
Kravitz, Len and Lance Dalleck. “Lactate Threshold Training.” University of New Mexico, https://www.unm.edu/~lkravitz/Article%20folder/lactatethreshold.html. Accessed 11 June 2019.
“Lactate Threshold 101.” Bicycling, 30 Apr. 2010, https://www.bicycling.com/training/a20017067/lactate-threshold-101/. Accessed 12 June 2019.
“Lactate Threshold Testing.” Exercise Physiology Core Laboratory, University of Virginia Health System, https://med.virginia.edu/exercise-physiology-core-laboratory/fitness-assessment-for-community-members/lactate-threshold-testing/. Accessed 12 June 2019.
Quinn, Elizabeth. “Lactate Threshold Training for Athletes.” VeryWell Fit, 19 Nov. 2018, https://www.verywellfit.com/lactate-threshold-training-3120092. Accessed 11 June 2019.
Sparacino, Alyssa. “How to Improve Your Lactate Threshold.” Shape, 4 Apr. 2019, https://www.shape.com/fitness/tips/how-improve-lactate-threshold-workouts. Accessed 12 June 2019.