From trial and error to precision, this episode unpacks why knowing how salty a sweater you are can unlock better fueling, hydration, and performance.
Episode Description:
Most runners know when their legs are tired, when their heart rate is higher than they'd like, and when their watch disagrees with reality, but far fewer know what’s actually happening in their sweat. And yet, hidden in those grains of salt is a story about performance, cramping, gut trouble, bonking, and why two athletes with identical race fuel and hydration plans can do the same race with wildly different outcomes.
In this episode of Legwork, Matt and Molly talk with Andy Blow — endurance athlete, sports scientist, and founder of Precision Fuel & Hydration, to explore the messy, fascinating world of electrolytes.
From Andy’s own battles with hypernatremia to the science behind sweat testing, the conversation pulls apart the myths, marketing, and misunderstandings that keep athletes guessing. It’s a journey from personal experiment to practical insight, showing how something as simple as knowing your sweat composition can reshape your entire fueling strategy and help you be a more informed athlete.
Whether your kit dries white after every run or leaves almost nothing behind, this episode helps you understand why it matters and how your electrolyte losses can guide smarter fueling and hydration.
They cover:
Whether you're training for your first 10K or trying to solve the mystery of mid-race cramps, this episode helps you understand your physiology — and build a hydration strategy that actually fits.
Chapter List:
00:00 Introduction to Precision Fuel and Hydration
03:09 Andy's Personal and Professional Career Path
05:41 Andy Blow's Athletic Journey and Founding Story
06:26 The Science Behind Sweat Testing and Electrolyte Needs
09:26 Growth and Evolution of Precision Fuel and Hydration
12:38 The Impact of COVID-19 on Business Strategy
16:11 Philosophy of Separation in Fuel and Hydration Products And the Myth That None of It Matters
20:56 The Role of Electrolytes in Performance
23:53 Insights from Formula 1 Experience
26:51 The Importance of Sweat Testing for Athletes
27:13 Getting Into The Science Of It All, T-Shirt Sizing The Salinity Of Your Sweat And The Case For Seeking Out That Information
37:38 Hydration Strategies for Athletes
42:35 Understanding Carbohydrate Ratios in Fueling
50:13 The Science of Osmolality in Sports Drinks
53:57 Evolving Beliefs in Sports Nutrition
59:01 Andy's Research on Sweat Salinity and Bone Health
01:03:37 The Role of Data in Athletic Performance
01:08:37 Future Innovations in Sports Nutrition and Gear