Episode 6 - Why Lactate Threshold Is the Real Ultra Performance Metric

In this episode, we unpack why lactate threshold is one of the most useful predictors of ultra performance, not because you race at threshold, but because it sets the ceiling for what “sustainable” feels like for hours. A higher threshold means your steady effort costs less energy, surges hurt less, and you drift into the red less often on climbs, headwinds, heat, and technical sections. You’ll learn a simple mental model (threshold = your red line), the three most common training mistakes (turning threshold into a weekly race, using wrong zones, living in the grey zone), and a practical weekly approach: one controlled threshold session, lots of truly easy running, plus durability work to hold effort late in long runs. The key takeaway: raise your threshold, and your “easy” pace gets faster, that’s real ultra performance.

Key references:

• Joyner, M. J., & Coyle, E. F. (2008). Endurance exercise performance: the physiology of champions. Journal of Physiology.
• Bassett, D. R., & Howley, E. T. (2000). Limiting factors for maximum oxygen uptake and determinants of endurance performance. Medicine & Science in Sports & Exercise.
• Seiler, S. (2010). What is best practice for training intensity and duration distribution in endurance athletes? International Journal of Sports Physiology and Performance.
• Stöggl, T., & Sperlich, B. (2015). Polarized training has greater impact on key endurance variables than threshold or high-intensity training. Frontiers in Physiology.
• Brooks, G. A. (2020). The lactate shuttle theory. Cell Metabolism.
• San Millán, I., & Brooks, G. A. (2018). Assessment of metabolic flexibility and its role in performance. Sports Medicine.
• Vanhatalo, A., Jones, A. M., & Burnley, M. (2011). Application of critical power in endurance sport.
• Training for the Uphill Athlete – Johnston, S., House, S., & Jornet, K.
• Endure – Alex Hutchinson
• Science of Ultra – multiple episodes on durability, fueling, and pacing.