EP441: I know V02, but what's lactate?

Welcome to my podcast. I am Doctor Warrick Bishop, and I want to help you to live as well as possible for as long as possible. I’m a practising cardiologist, best-selling author, keynote speaker, and the creator of The Healthy Heart Network. I have over 20 years as a specialist cardiologist and a private practice of over 10,000 patients. Episode Summary Dr. Warrick Bishop, a cardiologist, author, and CEO of the Healthy Heart Network, hosts this solo episode focused on fitness and longevity. He explores the differences between two key performance and health metrics — VO2max and lactate threshold — and explains why both matter for long-term health and aging. Key Takeaways: VO2max measures the maximum amount of oxygen your body can use during intense exercise, essentially reflecting the strength and efficiency of your cardiovascular delivery system. A useful analogy is comparing VO2max to engine size — a high VO2max is like having a V8 engine that delivers plenty of fuel to the muscles. Two athletes can have identical VO2max scores yet perform very differently, which is what led elite coaches to investigate lactate as an additional metric decades ago. Lactate threshold reflects mitochondrial efficiency — how well the body's cells actually use the oxygen delivered to them, not just how much oxygen arrives. When lactate levels begin to rise during exercise, it signals that the mitochondria are being overwhelmed and the body is switching to a less efficient energy pathway. Lactate threshold is considered the most powerful predictor of endurance performance and long-term metabolic health. VO2max and lactate threshold measure different things: cardiovascular fitness versus cellular and mitochondrial fitness, respectively. Elite athletes and their coaches have long used both metrics together to design more targeted and effective training protocols. Knowing your lactate threshold allows you to tailor training to raise that threshold, improving cellular efficiency at higher exercise intensities. Lactate testing is beginning to enter the longevity science space, complementing the already well-established use of VO2max as a marker for healthy aging.