In this episode, Dr. Dan Plews breaks down the science behind true endurance performance. We unpack the physiological demands of racing in extreme heat, how it accelerates carbohydrate use and glycogen depletion, and why athletes need smarter, more personalised fueling. Dan also dives into short-interval training—how micro intervals can replace long, low-intensity sessions and why they’re a game-changer for anyone training indoors or on limited time.

We also explore the role of micronutrition in driving training adaptations, the underrated importance of vitamin D for muscle health and recovery, and how antioxidants can shape your training outcomes. If you want to understand how to fuel better, train more effectively, and support long-term performance, this episode is packed with insight.

Takeaways

Heat massively increases physiological stress, accelerating carbohydrate use and dehydration.
Fueling strategies must adapt in extreme conditions, often starting with higher carb intake and tapering as the race progresses.
Cooling and hydration are essential to maintain performance in hot environments like Kona.
Individual physiological responses to heat vary, making personalised strategies crucial.
Micro/short intervals can replicate low-intensity training, making indoor training far more effective.
Short on–off interval methods improve performance efficiently, especially for time-poor athletes.
Micronutrition is critical for supporting training adaptations and recovery.
Excess antioxidants can blunt adaptation, so they should be used strategically and cycled.
Vitamin D is essential for muscle function, including repair, contraction, and mitochondrial energy production.
Vitamin D dosing matters—more isn’t better, but adequate levels are vital and often overlooked in athletes.

Chapters

00:00 Kona Race Recap and Insights

02:28 Physiological Challenges in Heat

05:49 Impact of Heat on Carbohydrate Use

10:47 Strategies for Endurance Athletes in Heat

17:46 Micro Intervals and Low Intensity Training

21:48 Short Intervals for High Performance

23:12 Micronutrition and Training Adaptations

30:38 The Role of Vitamin D in Muscle Function

Studies referenced:

Mougin et al., 2025 – Heat stress & dehydration on carbohydrate use

Giersch et al., 2025 – Heat acclimation in males & females

Wyckelsma et al., 2025 – Antioxidants & sprint interval training

Matomäki et al., 2024 – High-intensity microintervals vs low-intensity endurance