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July 17, 2024 • 1hr 48min
How Lactate & Metabolism Influence Performance
Perform with Dr. Andy Galpin
In this episode, Dr. Andy Galpin discusses lactate (often referred to as "lactic acid") and its essential roles in metabolism and athletic performance. He explains that lactate is commonly misinterpreted as a waste product responsible for muscle soreness and exercise fatigue. However, lactate actually has numerous positive effects on multiple organ systems and is critical for metabolism and as a signaling molecule.
Dr. Galpin covers the history of lactate research, explains the biochemistry of lactate production, and describes its various functions in the body. He also discusses how lactate relates to endurance performance, training "zones," the true causes of exercise fatigue, and whether lactate supplementation can improve performance.
How Lactate & Metabolism Influence Performance
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Key Takeaways
- Lactate is not a waste product or cause of muscle fatigue - It actually preserves muscle performance and has many beneficial effects throughout the body
- Lactate has three primary roles:
- Primary energy source for mitochondrial respiration
- Primary precursor for gluconeogenesis
- Signaling molecule/hormone
- Lactate positively affects multiple systems: Brain, heart, liver, wound healing, immune system, digestive system, etc.
- Lactate threshold is an important predictor of endurance performance, along with VO2 max and efficiency
- Metabolic flexibility is the ability to effectively use both fats and carbohydrates as fuel sources
- Training across intensity zones is optimal for improving lactate handling and overall performance:
- Low intensity (zone 1-2) for volume
- Moderate continuous for sustained efforts
- High intensity intervals for VO2 max
- Sprint intervals for peak power
- Lactate supplementation does not appear to improve exercise performance, despite theoretical benefits
- Continuous lactate monitors may be available to consumers in the near future
Introduction
In this episode, Dr. Andy Galpin discusses lactate (often referred to as "lactic acid") and its essential roles in metabolism and athletic performance. He explains that lactate is commonly misinterpreted as a waste product responsible for muscle soreness and exercise fatigue. However, lactate actually has numerous positive effects on multiple organ systems and is critical for metabolism and as a signaling molecule.
Dr. Galpin covers the history of lactate research, explains the biochemistry of lactate production, and describes its various functions in the body. He also discusses how lactate relates to endurance performance, training "zones," the true causes of exercise fatigue, and whether lactate supplementation can improve performance.
Topics Discussed
History of Lactate Research (4:21)
Dr. Galpin provides a brief history of lactate research, starting with its discovery in sour milk in 1708. Key milestones include:
- 1808 - Higher lactate concentrations found in hunted stags, linking it to stress/exercise
- 1843 - Lactate discovered in blood of deceased patients
- 1850s - Lactate found in blood of living people
- 1907 - Lactate identified as a byproduct of muscle contraction
- 1964 - "Anaerobic threshold" concept introduced by Wasserman
- 1983-2000 - George Brooks develops the "lactate shuttle" hypothesis
Lactate vs. Lactic Acid (13:58)
Dr. Galpin explains the difference between lactate and lactic acid:
- Lactic acid rarely exists in the human body
- At physiological pH and temperature, it quickly dissociates into a lactate anion and a hydrogen ion
- The term "lactic acid" is often incorrectly used when referring to lactate
"Lactic acid is almost never existed in the human body."
Roles of Lactate in the Body (22:43)
Dr. Galpin outlines the three primary roles of lactate:
- Primary energy source for mitochondrial respiration
- Lactate can be used directly by mitochondria for energy production
- Stimulates mitochondrial biogenesis (creation of new mitochondria)
- Primary precursor for gluconeogenesis
- Lactate can be converted back to glucose in the liver and kidneys
- Important for maintaining blood glucose levels during exercise
- Signaling molecule / hormone
- Has autocrine, paracrine, and endocrine effects
- Communicates between cells and tissues
Glucose, Mitochondria & Lactate (29:04)
Dr. Galpin explains the biochemistry of glucose metabolism and lactate production:
- Glucose (6 carbon molecule) is split into two 3-carbon pyruvate molecules
- Pyruvate is then converted to lactate
- Lactate can be used directly by mitochondria or transported to other tissues
- This process allows for rapid energy production without relying on oxygen
Metabolic Flexibility (36:09)
Dr. Galpin discusses the concept of metabolic flexibility:
- The ability to effectively use both fats and carbohydrates as fuel sources
- At rest and low intensities, fat is the primary fuel source
- As exercise intensity increases, reliance on carbohydrates increases
- Highly trained individuals can use more fat at higher intensities
"Metabolic flexibility does not stand for your ability to maximize fat burning. That is not at all what it is. It is exactly what I just said, the ability to use both effectively."
Lactate Efflux and Muscle Fiber Types (50:29)
Dr. Galpin explains how lactate moves between different muscle fiber types:
- Fast-twitch fibers produce more lactate during high-intensity exercise
- Slow-twitch fibers are better at utilizing lactate as a fuel source
- Lactate can be shuttled from fast-twitch to slow-twitch fibers
- This process allows for more efficient energy production overall
Alcohol, Fat Metabolism, and Exercise (55:42)
Dr. Galpin discusses the relationship between alcohol consumption, fat metabolism, and exercise:
- Alcohol metabolism in the liver can interfere with fat oxidation
- This can lead to increased fat storage, especially when consuming excess calories
- Exercise can help metabolize alcohol by increasing the demand for acetyl-CoA
- However, alcohol is not an effective fuel source for exercise performance
Lactate Supplementation and Performance (1:02:54)
Dr. Galpin addresses whether lactate supplementation can improve exercise performance:
- Theoretically, lactate supplementation should help buffer acid and improve performance
- However, current research shows minimal to no effect on exercise performance
- Other buffering agents like sodium bicarbonate and beta-alanine have shown more promise
- Lactate supplementation may have potential in medical applications (e.g., traumatic brain injury)
Cause of Exercise Fatigue (1:10:21)
Dr. Galpin explains that lactate is not the cause of exercise fatigue, contrary to popular belief. Factors contributing to fatigue include:
- Increased acidity (pH decrease) in muscle tissue
- Alterations in calcium signaling
- Changes in magnesium concentrations
- Disruptions in ATP production and utilization
- Sodium-potassium pump dysfunction
"Lactate is not the cause of muscle fatigue, but I haven't explained to you what is."
Investigating Lactate Levels (1:14:52)
Dr. Galpin discusses methods for measuring lactate levels and lactate threshold:
- Blood lactate analyzers are now widely available and relatively affordable
- Lactate threshold tests typically involve incremental exercise with blood sampling
- There are over 25 different methods for determining lactate threshold
- Continuous lactate monitors may be available in the near future
Interpreting Lactate Levels (1:33:01)
Dr. Galpin provides guidance on interpreting lactate levels:
- Resting lactate: 0.5-1.0 mmol/L is typical
- Lactate threshold: Often defined as 2.0 or 4.0 mmol/L
- Maximum exercise: Can reach 20-25 mmol/L in trained individuals
- Lactate threshold typically occurs around 70-85% of VO2 max in trained individuals
Intervening to Improve Lactate Handling (1:38:24)
Dr. Galpin outlines strategies for improving lactate handling and overall performance:
- Develop metabolic flexibility through varied training intensities
- Include a mix of training intensities:
- Low intensity (zone 1-2) for volume and mitochondrial adaptations
- Moderate continuous training for sustained efforts
- High-intensity intervals (85-95% VO2 max) for VO2 max improvements
- Sprint interval training (100%+ intensity) for peak power and anaerobic capacity
- Spend more time in lower intensities for recovery and volume, less time at higher intensities
- Consider individual goals and sport-specific needs when designing a training program
Conclusion
Dr. Galpin concludes by emphasizing the importance of understanding lactate's true role in physiology and performance. Rather than viewing it as a waste product or cause of fatigue, athletes and fitness enthusiasts should appreciate lactate's many beneficial effects throughout the body. By training across a spectrum of intensities and developing metabolic flexibility, individuals can enhance their ability to produce, utilize, and clear lactate effectively.
Ultimately, a well-rounded approach to training that incorporates various intensities and durations will lead to improvements in lactate threshold, VO2 max, and overall performance. This not only benefits athletic endeavors but also contributes to better overall health, energy levels, and cognitive function.
