I have been looking for some concrete study about the performance changes during sports when drinking water or a sports drink while doing the sport. Not after, not before. While, or during, if you prefer the wording.

I have found some studies that can be influenced by large sports drinks conglomerates such as Gatorade or Powerade.

Here is an example of one such studies that makes too many references to the "scientific" division of Gatorade, which I have difficulties accepting since it is not an independent study.

And here is the link for the Gatorade research.

Please keep in mind that the question is about performance improvement not about hydration requirements and recovery. It is evident we need proper levels of hydration and that sports depletes them in a measure that needs to be restored afterwards.

  • I don't think you can separate performance and hydration like you seem to want to. Johanvdw provided an answer that you seem to be dissatisfied with, but I think your demand for separating the two is unreasonable.
    – JasonR
    Sep 28 '11 at 15:12
  • The type of study you are looking for is dangerous. You would need to deplete your body of water and electrolytes intentionally depriving it of replenishment. People die from the effects of dehydration. I am not certian what you hope to learn by breaking them apart anyway. I cant imagine you would advocate denile of rehydration during a sporting event.
    – Chad
    Sep 28 '11 at 17:24

Not drinking sufficient water will lead to dehydration, especially in endurance sports.

If you search for dehydration and sports you will find a lot of references, I just give one example which also describes why dehydration is a problem in endurance sports.

MURRAY, R. Nutrition for the marathon and other endurance sports: environmental stress and dehydration. Med. Sci. Sports Exerc., Vol. 24, No. 9 Supplement, pp. S319-S323, 1992.

Key Points:

  1. During exercise, the body's ability to safely regulate internal temperature is influenced by the environment, exercise intensity, clothing, and the athlete's level of fitness and acclimation.
  2. Effective thermoregulation during exercise in the heat requires the evaporation of sweat. The onset of sweating during exercise is triggered by an increase in core body temperature.
  3. Dehydration compromises cardiovascular and thermoregulatory function, limits physical work capacity, and increases the risk of heat-related health problems.
  4. Physiological and behavioral adaptations help the body cope with the combined demands imposed by exercise and environment.
  5. Ad libitum fluid intake is insufficient to protect against dehydration.


It is clear that dehydration leads to worse prestations. See eg this synthetic test: http://journals.lww.com/acsm-msse/Abstract/1985/08000/Influence_of_diuretic_induced_dehydration_on.9.aspx

Therefore, it appears that competitive performance in trials of long duration (5,000 and 10,000 m) was affected to a greater extent by D than the shorter 1,500-m event, even though submaximal and maximal oxygen uptake was not altered.

Drinking water during an exercise can make sure that you remain hydrated [1] or get rehydrated[2] both improving the performance.


For intense prolonged exercise lasting longer than 1 h, athletes should consume between 30 and 60 g/h and drink between 600 and 1200 mL/h of a solution containing carbohydrate and Na+ (0.5 to 0.7 g/L of fluid). Maintaining proper hydration before, during, and after training and competition will help reduce fluid loss, maintain performance, lower submaximal exercise heart rate, maintain plasma volume, and reduce heat stress, heat exhaustion, and possibly heat stroke. http://www.sciencedirect.com/science/article/pii/S0899900704001029


Our results demonstrated that the swift replacement of the fluid loss in the dehydrated subjects was beneficial to exercise performance by rapidly correcting the disturbances in body fluid balance.


  • 1
    You are not answering the question (Did you bother to read it?) I am not denying what is obvious (Not drinking water leads to dehydration) Please reread the question and find an answer if you can. Thank you.
    – Joze
    Sep 28 '11 at 14:04
  • I've added one more link, but yes it seems obvious: not drinking leads to dehydration, and dehydration leads to worse prestations (I have added a link for that).
    – johanvdw
    Sep 28 '11 at 14:08
  • 2
    You are totally missing the point. I am not talking about performance being dehydrated. I am speaking about performance in a normal person (supposedly hydrated) taking water DURING (Please note DURING) a sports activity. And as dehydration is a negative condition it is also OBVIOUS that performance will be less satisfactory. Did you read the question?
    – Joze
    Sep 28 '11 at 14:13
  • 3
    Let's keep the tone civil, and assume good faith here.
    – Sklivvz
    Sep 28 '11 at 15:26
  • 3
    @Joze It depends on a sport, but with most sports when practiced intensely enough, you lose plenty of water and when not drinking, you are dehydrated. How do you want to address drinking "during" activity, but avoid this aspect? If you have some particular sport in mind for which dehydration is not an issue for some reason, please, add this into the question.
    – Suma
    Sep 28 '11 at 19:05

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