Hydration 3 of 4: Hydration and its Consequences – Behind the Scenes

As experience has often shown in the case of the sports footwear industry, science and business rarely go hand in hand. Tim Noakes’s latest book looks into several scientific theories that are actually commercially biased. Scientists in conflict of interest, sponsored researchers, scientific journals biased in the selection of their publication, cronyism and collusion … all of these things exist even in the field of science!



Again, we present to you a few more excerpts from “Waterlogged, The Serious Problem of Overhydration in Endurance Sports” part 3 of 4.

Here are some interesting points relating to the Gatorade Sports Science Institute (GSSI)


  • Starting in 1982, sales of Gatorade (brand of PepsoCo) grew steadily, with cumulative annual sales up to 2005 of at least 18 billion. (p.156)
  • The ACSM published its guidelines (1996 and 2007), which were firmly grounded on the dehydration myth. The ACSM is Gatorade-founded. (p.91)
  • The ACSM position stand: Exercise and Fluid Replacement (2007) was drawn up by 5 scientists who acknowledged they received funding or honoraria from the GSSI. (p.272 and 335)
  • Some other organism like the American Dietetic Association and Dietitians of Canada (2009) are making their recommendations based on the ACMS position stand. (p.273)
  • Many studies promoting the “dehydration myth” or the “salty sweater myth” are Gatorade-funded. (p.185)
  • Dr Murray, scientist, cofounder and director of the GSSI makes this statement: “Thirst is a poor indicator of your child’s need for fluids. By the time most active kids become thirsty, they have already lost important fluids and electrolytes and may be dehydrated. While a cool drink of water may feel satisfying, it doesn't supply the energy kids need to keep playing hard and having fun. A sports drink like Gatorade is the best way to keep kids both cooled and fueled.” (p.209)
  • GSSI has been promote overdrinking by inappropriate advice. (p.309)


Exercise-Associated Hyponatremia (EAH)


  • More than 1600 cases of EAH have been reported in the scientific literature or documented at the Hawaii Triathlon. (p.255)
  • EAH become the single greatest risk to the health of endurance athlete. (p.327)
  • EAH can cause brain swelling, coma, convulsions and respiratory failure. (p.255)
  • Overhydration causes the vast majority of cases of EAH. (p.268)
  • Kidneys have a limited capacity to excrete a fluid load. The human intestine can absorb fluid faster than the kidneys can excrete the absorbed fluid. (p.26)
  • Intestine can store perhaps as much as 1.2L of fluid before diarrhea develops. (p.27)
  • There is no appropriate reference showing that electrolyte ingestion during exercise can prevent EAH.



The Epidemic of EAH that struck especially North America in the 1990 was created by factors that caused those at risk to drink to excess during exercise. (p.292)


  • Sport drinks will, if overconsumed, result hyponatremia. The administration of normal saline (0.9%) also increase fluid overload. (p.287)
  • EAH will occur only in those who overdrink persistently during prolonged exercise; have SIADH (syndrome of inappropriate ADH); who osmotically inactivate circulating sodium, storing it in an osmotically inactive, intracellular store. (p.291)
  • 2 most important risk factors are: weight gain during the race and race duration excessing 4 hours. (p.253)
  • If the body weight does not fall by perhaps 2-3 kg (4-6lbs) during the course of an ironman triathlon, then the athlete is already overhydrated by that amount. (p.260)


To conclude (with the words of Tim Noakes, p.353)


  1. Your body will tell you what it needs, if you just listen.
  2. So drink only ad libitum… that is, according to the dictate of thirst.
  3. Dehydration is not a disease!
  4. Understand that much of what you currently believe about your personal well-being is the result of targeted manipulations by industries whose principal focus is their commercial fitness and not necessarily your health or safety!


Don’t miss our last post of this series: “What’s Next?”