The Lactic Acid Journey: Insights into its Impact on Runners.

Science - lactic acid

Lactic Acid Journey – Before, During and After a Run. What is it?!!

Lactic acid, a natural byproduct of intense exercise, plays a pivotal role in the physiological responses experienced by runners before, during, and after a run. Understanding the nuanced effects of lactic acid on the runner’s body is crucial for optimizing training and performance.

Before Running:

As runners prepare for their activity, the body anticipates the impending demands by initiating glycolysis, the process through which carbohydrates are broken down for energy. Lactic acid begins to accumulate when glycolysis outpaces the rate at which pyruvate enters the mitochondria for energy conversion. This buildup is more pronounced during sustained high-intensity exercise when oxygen delivery to the muscles lags. That all sounds very complicated – let’s break it down:


  1. : This is a small molecule that’s produced when your body breaks down sugars (like glucose) for energy during a process called glycolysis.
  2. Mitochondria: Think of these as tiny power plants within your cells. They’re responsible for producing energy in a form your body can use (ATP).
  3. “Enters the Mitochondria”: This means that pyruvate moves from one part of the cell to another, specifically into the mitochondria.

So, when we say “pyruvate enters the mitochondria,” it’s describing a step in the process where the molecule produced from breaking down sugars moves into the cell’s energy-producing factories to undergo further reactions that ultimately help generate energy for the cell. Still complicated but is the best I can do.

During Running:

  1. Slowed Pace:
    • Why does it happen? The burning sensation associated with lactic acid buildup signals the body to slow down automatically. This is because when the body senses high levels of lactic acid, it interprets it as a sign that the muscles might not be getting enough oxygen to efficiently process pyruvate (a byproduct of glucose breakdown).
    • What do runners feel? Runners may experience a sense of fatigue, discomfort, or a burning sensation in their muscles. This prompts a natural instinct to ease off the pace to allow the body to catch up with oxygen demands.
  2. Impaired Coordination:
        • Why does it happen? Lactic acid interferes with the normal process of muscle contractions, affecting the coordination required for efficient running. It disrupts the signals between the nervous system and muscles, leading to a deterioration in movements like stride length and arm drive.
        • What do runners feel? Runners might notice a lack of fluidity in their movements, with strides feeling less controlled. Coordinated and efficient running becomes a challenge due to the impact on muscle contractions.

      shin splints

  3. Decreased Power:
    • Why does it happen? The accumulation of lactic acid reduces the muscles’ ability to generate power and strength. This makes it harder for runners to maintain their speed, particularly during uphill sections or when attempting a final sprint.
    • What do runners feel? Runners may experience a sense of weakness or heaviness in their legs, making it difficult to generate the force required for powerful strides. Uphill running becomes particularly challenging due to decreased muscle power.
  4. Reduced Endurance:
    • Why does it happen? Elevated levels of lactic acid contribute to quicker muscle fatigue. This means that the muscles tire more rapidly, affecting the runner’s ability to sustain a given pace over an extended period.
    • What do runners feel? Runners may find that they tire more quickly than usual, and sustaining a fast or moderate pace becomes increasingly difficult. Endurance is compromised as the muscles struggle to maintain the necessary effort.
  5. Impact on Fast Twitch Muscles:
      • Why does it happen? Fast twitch muscle fibers, which are crucial for explosive movements and sprints, are more sensitive to the effects of lactic acid compared to slow twitch fibers. This results in a more rapid decline in form and speed.
      • What do runners feel? During high-intensity efforts, runners may notice a more pronounced decline in performance as the fast twitch muscles, responsible for bursts of speed, become fatigued more quickly.

    lactic fast twitch

Lactate Threshold:

  • Why does it matter? The lactate threshold is a crucial factor for runners because it represents the point at which lactic acid starts to accumulate rapidly. Staying below this threshold is essential for sustaining optimal performance.
  • What do runners feel? If runners exceed their lactate threshold, they may experience a sudden and significant decrease in power and endurance. The body’s ability to efficiently clear lactic acid diminishes, leading to a quicker onset of fatigue and a decline in overall running performance. Maintaining a pace below the lactate threshold is key to optimizing both speed and endurance during a run.

After Running:

Lactic Acid Post-Exercise Fatigue and Burn:

  • Runner’s Experience: After running, many runners experience temporary muscle fatigue and a burning sensation. This is often attributed to the presence of lactic acid, a byproduct of energy metabolism during exercise.
  • Recovery Focus: It’s important to note that while lactic acid contributes to immediate fatigue, it doesn’t directly cause muscle soreness. Soreness is more closely linked to microscopic muscle fiber tears and inflammation.

Lactic acid

Best Practices for Lactic Acid Clearance:

  1. Pacing:
    • Runner’s Experience: Gradual pacing helps manage exertion levels effectively. Redlining early in a run can lead to rapid lactate accumulation and fatigue.
    • Recovery Focus: Start at a comfortable pace and gradually build into the goal pace to allow the body to adapt and manage lactate levels.
  2. Endurance Building: Try the Long Slow Distance method – read here
    • Runner’s Experience: Aerobic base training at lower intensities lays the foundation for improved endurance, enabling the body to handle harder efforts with less lactate buildup.
    • Recovery Focus: Include lower-intensity training sessions to enhance aerobic capacity, facilitating better lactate clearance during more intense efforts.
  3. Interval Training:
    • Runner’s Experience: Intervals involve alternating between high and low-intensity efforts. This conditions the body to clear lactate faster, improving its ability to handle spikes during competition.
    • Recovery Focus: Allow sufficient recovery between intervals to ensure effective lactate clearance, preventing excessive accumulation.
  4. Proper Fueling:
    • Runner’s Experience: Inadequate carbohydrate intake can lead to increased lactate production. Proper fueling ensures sufficient energy for runs and maintains glycogen stores.
    • Recovery Focus: Consume a balanced diet with an emphasis on carbohydrates to support recovery and replenish glycogen stores.


Strategies for Lactic Acid Reduction:

  1. Cadence Drills:
    • Runner’s Experience: Form drills that focus on increasing leg turnover can improve running economy and reduce submaximal lactate levels.
    • Recovery Focus: Incorporate cadence drills into training to enhance running efficiency and minimize lactate production.
  2. Good Running Form:
    • Runner’s Experience: Efficient stride minimizes braking forces and energy leakage, reducing unnecessary lactate production.
    • Recovery Focus: Work on developing and maintaining good running form through drills and exercises to optimize energy use and reduce post-run fatigue.
  3. Consistent Pace:
    • Runner’s Experience: Avoiding dramatic pace surges helps prevent sudden spikes in lactate levels, allowing for more consistent effort.
    • Recovery Focus: Train to maintain an even pace during workouts and races to manage lactate production and optimize performance.
  4. Altitude Training:
    • Runner’s Experience: Exposure to moderate altitude can enhance lactate clearance by promoting mitochondrial efficiency and capillary density.
    • Recovery Focus: Consider altitude training as part of a well-structured training plan to improve the body’s ability to handle lactate.
  5. Massage:
    • Runner’s Experience: Post-run massage assists in lactate removal, expediting recovery for subsequent high-intensity sessions.
    • Recovery Focus: Include regular massages in the recovery routine to reduce muscle tension and facilitate the removal of metabolic byproducts like lactate.

lactic acid massage

Overcoming High Lactic Acid Levels:

  1. Mental Toughness:
    • Runner’s Experience: Expecting and embracing the burn during intense efforts is crucial for developing mental resilience to tolerate discomfort.
    • Recovery Focus: Mental toughness is cultivated through consistent, challenging training. Embrace discomfort during workouts to build the mental strength needed for competition.
  2. Pain Tolerance:
    • Runner’s Experience: Enduring pain during demanding interval sessions with short rest periods helps build confidence and tolerance for discomfort.
    • Recovery Focus: Integrate high-intensity interval sessions into training, gradually increasing intensity to improve pain tolerance and mental fortitude.

Beyond the Lactate Threshold:

Pushing Through the Lactic Acid Threshold:

  • Runner’s Experience: Pushing through the lactate threshold challenges the body to adapt and become more efficient in buffering and removing lactate.
  • Recovery Focus: Incorporate structured training sessions that involve pushing beyond the lactate threshold, gradually increasing intensity to promote adaptation and improve lactate clearance.

Recruiting More Muscle Fibers:

  • Runner’s Experience: Tapping into less-fatigued fast and slow twitch muscle fibers helps maintain form and stride length during prolonged efforts.
  • Recovery Focus: Include varied workouts that target different muscle fiber types to improve overall muscle endurance and efficiency.

Finishing Strong:

  • Runner’s Experience: Focusing on driving all-out during the challenging final portion of a race, where lactate levels are highest, can be mentally and physically demanding.
  • Recovery Focus: Train specifically for finishing kicks, incorporating simulated race scenarios in training to prepare the body and mind for the demands of a strong finish. Ensure that the overall race strategy allows for a strategic and well-timed surge.

By understanding the physiological responses to running and implementing targeted recovery strategies, runners can optimize their performance, reduce post-run discomfort, and enhance overall endurance.

In conclusion, the journey through the nuanced effects of lactic acid on a runner’s body unveils a dynamic interplay before, during, and after a run. Before the race commences, the intricate dance between glycolysis, pyruvate, and the mitochondria sets the stage for energy conversion, underlining the complexity of the body’s preparation. During the run, the sensory experiences of slowed pace, impaired coordination, decreased power, and reduced endurance reveal the impactful consequences of lactic acid accumulation, particularly on fast twitch muscles. The lactate threshold emerges as a pivotal marker, guiding runners to maintain optimal performance. Post-run, the burn and fatigue, attributed to lactic acid, prompt a strategic approach to recovery.

Navigating this physiological landscape requires disciplined pacing, endurance building, and interval training. Proper fueling and strategic reduction strategies, including cadence drills and good running form, play key roles. Overcoming high lactic acid levels demands mental toughness and enhanced pain tolerance. Thus ensuring runners push beyond the lactate threshold and finish strong. Through meticulous understanding and strategic recovery measures, runners can harness lactic acid’s challenges, transforming them into stepping stones toward optimized performance and enhanced endurance.

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Happy running!

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