The Endurance Science Podcast with Matt Carpenter

The Science of Endurance is back and better than ever!

New weekly series following my Journey to London Marathon 2027, where I'll be using my own training to talk about the science behind training, nutrition, supplementation, shoes and more, all in a bit to help you run faster, run better and understand the science behind how we train.

I'll be running London 2027 for Hospice UK, a fantasitc charity that supports people at the end of their lives. Any donations along this journey will be hugely appreciated - and thanks for tuning back in!

https://www.justgiving.com/page/matthew-carpenter-6

For years, rapamycin has been hailed as the closest thing we have to a real longevity drug, taken by biohackers, prescribed by telehealth clinics, and promoted across the wellness internet.
The first proper randomised controlled trial combining it with exercise in older adults just dropped, and the results are a wake-up call about how we treat supplement hype.

In this episode, i discuss a major topic of my PhD, exognoeus ketones. Is the hype worth it? What does the research say? Do ketones really replicate altitude training? All are discussed in this episode.

References:
https://journals.physiology.org/doi/full/10.1152/ajpendo.00264.2022

https://physoc.onlinelibrary.wiley.com/doi/full/10.1113/JP284346

In this episode, I dives deep into the science of caffeine, revealing how understanding its mechanisms, dosing, and timing can help endurance athletes maximise their performance safely and effectively.Main topics:
The science behind how caffeine enhances endurance performance
Optimal caffeine dosing strategies (3-6 mg/kg) and the effect of individual differences
Timing of caffeine intake before and during races for maximum benefit
The history of caffeine's status in anti-doping regulations and its legal use today
Differences between coffee and pure caffeine supplements
Practical tips for training and race day caffeine use
The importance of personal experimentation and understanding individual responses

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.