The Endurance Science Podcast with Matt Carpenter

Matt Carpenter

A podcast that cuts through the endless noise and misinformation social media noise presents us, and discusses what the science really says about endurance performance.

Episodes

  1. 31 MAR

    The New Science of Lactate

    For as long as I can remember, I was told that lactate was the enemy, the toxic waste product that made my legs burn and forced me to slow down. It turns out almost everything I believed about it was wrong. In this episode, I trace the remarkable story of how lactate went from metabolic villain to one of the most important molecules in exercise physiology. I start with George Brooks, the UC Berkeley professor who spent four decades building the lactate shuttle theory, the idea that lactate isn't waste but a fuel, a gluconeogenic precursor, and a signalling molecule that shuttles between cells, tissues, and organs. Then I dig into a stunning 2023 paper from Craig Thompson's lab at Memorial Sloan Kettering that takes the story even further: lactate doesn't just feed the mitochondria, it activates the electron transport chain without even being metabolised. It's a messenger that tells your mitochondria to produce more ATP, suppresses glycolysis, and shifts your energy system toward oxidative phosphorylation. I explore what all of this means for how we think about the lactate threshold, pacing, interval training, recovery, and even immune function. If you've ever pushed into that burning zone on a hard run or ride, this episode will change how you think about what's happening inside your body. References: Cai, X. et al. (2023). Lactate activates the mitochondrial electron transport chain independently of its metabolism. Molecular Cell, 83, 3904–3920. Brooks, G.A. (2018). The Science and Translation of Lactate Shuttle Theory. Cell Metabolism, 27, 757–785. Brooks, G.A. et al. (2022). Tracing the lactate shuttle to the mitochondrial reticulum. Experimental & Molecular Medicine, 54, 1332–1347. Hui, S. et al. (2017). Glucose feeds the TCA cycle via circulating lactate. Nature, 551, 115–118. Leija, R.G. et al. (2024). Enteric and systemic postprandial lactate shuttle phases and dietary carbohydrate carbon flow in humans. Nature Metabolism, 6, 670–677. Brooks, G.A. (2023). What the Lactate Shuttle Means for Sports Nutrition. Nutrients, 15(9), 2178.

    19 min
  2. 24 FEB

    Why Fat Oxidation is More Important Than you Think

    In this episode of the Endurance Science Podcast, I discuss the critical role of fat oxidation in endurance exercise. I discuss how fat burning works during exercise, its importance in various event durations, and the methods to enhance fat oxidation. The discussion highlights recent research findings, practical strategies for athletes, and the significance of dietary modifications to improve performance. While carbohydrate consumption is often prioritised, understanding and improving fat oxidation is essential for long-distance endurance athletes, and that's what this episode is all about. Takeaways Fat oxidation is crucial for endurance performance, especially beyond two hours. Carbohydrate is the primary energy source at higher intensities, but fat stores are virtually unlimited. Research shows a correlation between fat oxidation rates and performance in long-distance events. Fat oxidation becomes increasingly important as exercise duration extends beyond two hours. Training volume significantly enhances the body's ability to burn fat. Reducing carbohydrate intake can improve fat oxidation rates. Periodizing carbohydrate intake may help maintain performance while increasing fat oxidation. Testing fat oxidation rates can provide insights into an athlete's metabolic efficiency. Athletes should focus on both training and dietary strategies to optimize fat burning. Understanding the balance between fat and carbohydrate metabolism is key for endurance athletes. References: https://journals.physiology.org/doi/epdf/10.1152/japplphysiol.00855.2015 https://link.springer.com/article/10.1007/s00421-016-3333-y https://physoc.onlinelibrary.wiley.com/doi/full/10.14814/phy2.70752

    32 min
  3. 17 FEB

    How Much Carbohydrate Do You Need?

    In this episode of the Endurance Science podcast, I dig deep into the complex role of carbohydrates in enhancing endurance performance. We discuss how carbohydrates are stored in the body, the physiological mechanisms behind their utilization during exercise, and the varying recommendations for carbohydrate intake based on exercise duration and intensity. The conversation highlights the importance of both muscle and liver glycogen, the impact of carbohydrate ingestion on performance, and the emerging research on carbohydrate mouth rinsing. Carbohydrates improve endurance performance through various mechanisms.Muscle glycogen is primarily stored in muscles, while liver glycogen helps maintain blood glucose levels.Carbohydrate ingestion during exercise can spare muscle glycogen and prevent hypoglycemia.The cephalic response to carbohydrate can enhance performance even without ingestion.10 grams of carbohydrate per hour can be sufficient for maintaining blood glucose during exercise.Individual responses to carbohydrate intake can vary significantly among athletes.Carbohydrate mouth rinsing may provide performance benefits without actual ingestion.Breakfast is crucial for maintaining liver glycogen levels before exercise.Carbohydrate needs differ based on the duration and intensity of the activity.Future research should focus on individual carbohydrate requirements for endurance athletes. References: https://journals.physiology.org/doi/full/10.1152/japplphysiol.00861.2025 https://journals.humankinetics.com/view/journals/ijspp/21/2/article-p258.xml https://journals.physiology.org/doi/full/10.1152/japplphysiol.91394.2008

    39 min

About

A podcast that cuts through the endless noise and misinformation social media noise presents us, and discusses what the science really says about endurance performance.

You Might Also Like