Lactic acid is a by-product of anaerobic exercise, such as running at an intense pace where the body requires more oxygen than the lungs can provide. It is created when the body breaks down glucose and other carbohydrates for energy. Lactic acid is often associated with the burning sensation in muscles during intense exercise and has been a subject of debate in the running community.

It is a common myth that muscle soreness after exercise is caused by lactic acid trapped in the muscles. However, studies have found that this is not true. Lactic acid is not the cause of muscle soreness, but rather a by-product of the body's energy production during intense exercise.

The body clears lactic acid when it develops, but it may not be able to keep up when the levels start to increase rapidly, leading to muscle fatigue and reduced muscle contraction. Lactic acidosis caused by intense exercise is usually temporary and can be prevented by gradually increasing exercise intensity, staying hydrated, getting enough sleep, and allowing for proper recovery between bouts of exercise.


  1. How It's Produced: When you exercise, your body uses glucose (sugar) for energy. With enough oxygen, glucose turns into ATP (energy for muscles). But in high-intensity activities like sprinting, there's not enough oxygen, and your body switches to anaerobic metabolism. This process produces energy quickly but also leads to lactic acid buildup.
  2. Effects of Lactic Acid: When lactic acid accumulates in your muscles, it can cause that familiar feeling of discomfort and fatigue during intense workouts. However, lactic acid isn't entirely harmful – it can be converted back into glucose and used as energy, particularly in endurance activities like long-distance running.
  3. Managing Lactic Acid: You can train your body to handle lactic acid better. Gradually increasing your workout intensity and duration helps your body become more efficient at dealing with lactate. Additionally, a diet rich in carbohydrates and electrolytes can aid in reducing lactic acid buildup.

In summary, lactic acid is a byproduct of anaerobic metabolism during intense exercise. It can cause fatigue and soreness but also serves as a potential energy source. Through proper training and nutrition, you can better manage lactic acid buildup, improving your running performance and comfort.


Lactic acid affects running performance by contributing to muscle fatigue and discomfort. As running intensity increases, the body's production of lactic acid also increases. At a certain point, the body may no longer be able to convert lactate back, leading to a rapid increase in lactic acid levels. This can result in muscle fatigue, reduced muscle contraction, and the sensation of pain, heaviness, and burning in the muscles. However, it's important to note that lactic acid itself is not the direct cause of muscle fatigue. Recent studies have shown that lactic acid, or more accurately, lactate and/or hydrogen (H+) ions, may not be a major cause of skeletal muscle fatigue. In fact, there is evidence suggesting that lactate/H+ may have ergogenic effects during exercise. Therefore, while lactic acid is associated with muscle fatigue and discomfort, its role in exercise performance is still a topic of ongoing research and debate.