In Part 9, Professor Tim Noakes describes the sports drink industry’s response to proof that exercise-associated hyponatremic encephalopathy (EAHE) is not due to sodium deficiency and cannot be prevented by drinking electrolyte-containing sports drinks. He explains how he and his colleagues discovered that, rather than resulting from sodium deficiency, EAHE develops from overhydration. He then outlines the preponderance of evidence that demonstrates it is difficult, perhaps even impossible, for humans living in normal conditions to develop a sodium deficiency. Nevertheless, the sports drink industry and its proxies in sports medicine and sports science continued to promote the economically advantageous but scientifically unsupportable overconsumption of sodium-containing drinks during exercise.