In this case, the acetyl-CoA will feed into a biochemical pathway called the citric acid cycle , and your liver cell will use the energy it extracts by oxidizing these carbons to store energy in the form of adenosine triphosphate, or ATP. By so doing, however, the liver merely satisfies its own requirements and not those of other cells. The liver also needs to turn the lactic acid into glucose. It does so through a process called gluconeogenesis. When lactic acid is abundant in your liver cells after exercise, the gluconeogenesis pathway is a little bit different from the one your liver employs at other times.
It begins in the mitochondria, where an enzyme called pyruvate carboxylase adds a molecule of bicarbonate to pyruvate and converts it to oxaloacetate. This reaction requires energy expenditure in the form of a molecule of ATP. Next, another enzyme called mitochondrial PEP carboxykinase converts oxaloacetate into phosphoenolpyruvate, or PEP, and free carbon dioxide. This step also requires energy investment in the form of a molecule of GTP. I have vivid memories of joining my dad as he laid on the ground with his legs elevated after a long run or intense biking session.
My dad had been taught what many people believed about lactic acid: that it was a cause of fatigue and muscle soreness, and that it had to be removed in some way to help you recover and avoid soreness. As a young athlete, I often heard these same things being echoed by my coaches and I believed it to be true.
The soreness that you feel in your muscles post-workout is due to microscopic tears in the muscle tissue that rebuilds to help you get stronger. So, what is this lactic acid everyone was going on about? What does it do, and do I need to get rid of it? Read on to find out. Most people associate lactic acid with intense exercises, like sprinting or heavy lifting, and rightly so. Lactic acid is a by-product of glycolysis, one of the metabolic processes the body uses to produce energy during intense exercise.
Lactic acid is the collective term used to describe the lactate and hydrogen ions that are by-products of this process. Lactic acid is formed within the muscle cells during glycolysis to clear the cells of accumulating pyruvate, a by-product of glycolysis. While still in the muscle cells, the hydrogen ion is what is responsible for lowering the pH of the muscle tissue, making it more acidic.
This decrease in the muscle pH, known as acidosis, can lead to some of the burning sensations felt in the muscles during intense exercise.
The good news, however, is that lactic acid is more of a helper to our muscles since it ultimately provides energy. That changes during hard exercise. Related: Muscle spasms and cramps: Causes and treatments. When you break into an all-out sprint your muscles start working overtime. The harder you work, the more energy your muscles need to sustain your pace. Luckily, our muscles have built-in turbo-boosters, called fast-twitch muscle. Unlike slow-twitch muscle, which we use for most of the day, fast-twitch muscle is super-effective at producing lots of energy quickly and does so anaerobically, Gleeson said.
Fast-twitch muscle also uses glycolysis to produce energy, but it skips harvesting energy from pyruvate, a process that takes oxygen.
Instead, pyruvate gets converted into a waste product, lactic acid, and released into the bloodstream. It's a common misconception that muscle cells produce lactic acid when they can't get enough oxygen, Gleeson said. Your muscles are getting plenty of oxygen," he said.
But in times of intense energy needs, muscles switch to anaerobic respiration simply because it's a much quicker way to produce energy. Muscle cells aren't the only sources of lactic acid. Red blood cells also produce lactic acid as they roam the body, according to the online text Anatomy and Physiology published by Oregon State University.
Typically, the liver will break down excess lactate in the blood. This can result in a more severe buildup of lactate, which doctors refer to as lactic acidosis. This article provides tips for preventing and reducing exercise-induced hyperlactatemia. We also outline other causes of lactate buildup and lactic acidosis. A buildup of lactic acid in the muscles during or following exercise is not harmful.
In fact, some experts believe it can be beneficial. In small amounts, lactic acid can:. However, many people find that the muscle pain and cramps from lactic acid buildup negatively affects their workouts.
Keeping the body hydrated during exercise gives it the best chance of breaking down any excess lactic acid. People can ensure they stay hydrated by drinking plenty of water. The body starts to produce lactic acid when it is low in the oxygen necessary to convert glucose into energy.
Breathing deeply will help deliver oxygen to the muscles, thereby slowing the production of lactic acid. When a person feels the effects of lactic acid buildup, they can slow down and reduce the intensity of their workout. This will allow blood oxygen levels to recover.
Lightly stretching the muscles after a workout can help to alleviate any burning sensations or cramps that lactic acid buildup may cause.
In most cases, lactic acid buildup is a harmless response to strenuous exercise and will go away on its own. Once the body has used the resulting lactate for energy, the liver breaks down any excess in the blood. For a long time, experts thought that lactic acid was responsible for delayed onset muscle soreness DOMS following exercise.
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