Hydration, Electrolytes & Exercise Nutrition

"For a century, athletes were told the same two things: never let yourself get thirsty, and carbohydrate is king. Both contain a grain of truth wrapped in a great deal of myth. The body is not a leaky bucket that must be topped up by the minute, and it is not a furnace that must be force-fed sugar. It is a superbly regulated system that asks only one thing of you: match what you take in — water, salt, and fuel — to what the session actually demands."

Few topics in nutrition generate more confident-sounding advice and more genuine confusion than hydration and fuelling around exercise. We are told to drink eight glasses a day, to "stay ahead of thirst," that even slight dehydration wrecks performance, that we constantly leak electrolytes, that sugary sports drinks are essential — and, simultaneously, that they are poison. Marketing has filled the gap left by misunderstanding with a multibillion-dollar industry of bottles, powders, tablets, gels, and "enhanced" waters.

This book replaces the noise with physiology and evidence. It explains how the body manages water (Chapters 2–3), electrolytes (Chapter 4), and heat and sweat (Chapter 5); what dehydration (Chapter 6) and its opposite, overhydration (Chapter 7), actually do; how to build a hydration strategy (Chapter 8); and how to fuel training and competition with carbohydrate (Chapter 9) and the rest of the around-training diet (Chapter 10). It then audits the products (Chapter 11), addresses special contexts — heat, cold, altitude, populations, and cramps (Chapter 12) — and assembles a practical framework (Chapter 13).

This is the fifth and final book of Collection F (Foundational Nutrition & Metabolism). It builds on F1 (energy balance), F2 (macronutrients), F3 (micronutrients, including the electrolyte minerals), and F4 (body composition — of which body water is the largest single component), and on the renal and cardiorespiratory physiology of A8 and A5. It is written for everyone who moves — recreational exercisers, competitive athletes, coaches, dietitians, students, and clinicians-in-training — at a university level while staying friendly and practical.