Do You Need Only 10g per Hour of Carbs? Tim Noakes Thinks So / Pacing Implosions: When Regulation Fails

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Show notes

This week on Spotlight, we dive DEEP into the world of physiology, pacing, fatigue and the brain. Using some enthralling races from Kona and Chicago at the weekend, and your Discourse questions and comments, we explore how pacing 'errors' happens, and the physiological consequences of those mistakes. We kick off of with our Discourse Digest segment (00:00) and news that Femke Bol will take a swing at the 800m next year. An exciting development, but what will it involve in terms of training and tactics, and what can we expect from the Dutch star?

We then move on to the Chicago Marathon (15:56), won by Jacob Kiplimo, emerging as a real star of the Marathon. His success contained a very specific type of "failure" though, as he was on course to break the World Record right up to 35km, and then...physiology hit. Ross explains how fragile pacing is for elite marathoners, and why physiology collected on its 'loan' for Kiplimo. Another physiological "failure" happened in the Kona Ironman (29:26) where Lucy Charles-Barclay and Taylor Knibb raced so aggressively that they first rode and then ran each other to the point of proverbial physiological destruction. We explore how pacing in the context of a warm day caused those dramatic scenes.

In Centre Stage (44:57), it's all about the carbs. Tim Noakes has a paper arguing that you need only 10g/h of glucose during exercise. He uses his "Central Governor" model to explain how the brain is monitoring and regulating blood glucose level to protect the brain, such that the 90g per hour or more being consumed by elites is wasteful and unnecessary, part of an 'old model'. We don't see it the same way, and Ross explains concepts of regulation of performance by the brain, a subject he did his PhD thesis on. We discuss heat, altitude, and fuel, to unpack how the truth behind fatigue, performance and pacing regulation, unlocking more insight on those pacing implosions in Chicago and Kona.

In Ross Replies (1:06:59), listener Ian asks a great question about using data from a specific test where you lie down then stand up, and use HR to tell you how recovered you are. Ross explains why that test exists, its limitations, and offers tips for how to make more of data, while avoiding some traps.

And Finally (1:21:31), we see again that cycling is allergic to the truth, Gareth learns the truth about NZ Rugby Representation, and we tip our hats to Natalie Grabow.

Links

• A race report from that dramatic Kona women's race
• The full Taylor Knibb statement
• The Noakes Tweet
• Ross' PhD thesis on Anticipatory Regulation
• Article on orthostatic testing for HR and HRV
• The Six who Sat podcast that Gareth mentioned on the show

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