Sports Medicine Research: In the Lab & In the Field: Water, Water Everywhere…but How Much Should You Drink? (Sports Med Res)


Wednesday, February 1, 2012

Water, Water Everywhere…but How Much Should You Drink?

Hydration Strategies of Runners in the London Marathon

Williams J, Tzortziou-Brown V, Malliaras P, Perry M, and Kipps C. Clin J Sport Med. 2012 [Epub Ahead of Print].

Exercise-associated hyponatremia (EAH) is a condition which occurs during or after prolonged endurance exercise, and is defined as a serum sodium concentration of less than 135mmol/L. EAH is commonly caused by excess fluid intake during activity and may result in altered mental status and in some cases death. Therefore, Williams and colleagues utilized a questionnaire to assess runners’ hydration plans for before, during, and after the London Marathon, and evaluated how closely these plans followed the current recommendations. Of 232 invited participants, 217 (66 women, 151 men) completed the questionnaire. Of the respondents, 208 (96%) had a “plan regarding prerace fluid intake during the race”. Analysis revealed that 45 (22%) participants planned to drink from all 24 water stations, potentially a total consumption of 7.9 liters of fluids. The median total volume participants planned to drink was approximately 1.2 liters. One hundred and ninety one (88%) participants reported a fluid-intake plan for 6 hours post-race. Again, the participants planned to consume a median total volume of 1.2 liters of fluids. When asked about the source of information, 93% of participants stated that their information was gained on race day through the London Marathon magazine or friends with running experience. Other factors that influenced runners’ drinking strategies were temperature (33%) and thirst (25%). The questionnaire further revealed that 141 (65%) participants “heard of hyponatremia” while only 77 (37%) proved to have a “basic understanding of hyponatremia”. The analysis demonstrated a severe lack of understanding regarding appropriate fluid intake guidelines. While sources (EAH Consensus Development Conference statement, International Marathon Medical Directors Association) recommend that runners should “drink to thirst,” only 25% (54) of respondents reported thirst was a factor in determining fluid intake. Despite the relatively low understanding of fluid intake guidelines, 151 (70%) stated in the questionnaire that they read the official race magazine, provided to all participants of the London Marathon, which included appropriate fluid intake recommendations.
Clearly, there is a gap in understanding between provided information on fluid intake and actual practices. This study demonstrates that more needs to be done to educate runners on appropriate fluid intake plans before, during, and after races. The authors highlighted that the official race magazine would be an excellent source of information. While this publication already has guidelines for proper appropriate fluid intake, the author states the information was “located near to the back of the magazine, the official medical advice was less prominent than advertising features about sports drinks in the early section which, of note, make no mention of hyponatremia or the potential dangers of excessive drinking.” While EAH and its causes are well understood the information has not yet reached our athletes. In conclusion the authors call for changing the drinking behavior of runners through more effective education. What do you think? Have you had, or know someone who has, struggled with EAH? What are some strategies that you think would be most effective in informing this population?

Written by: Kyle Harris
Reviewed by:  Jeffrey Driban

Related Posts:
Williams J, Tzortzioubrown V, Malliaras P, Perry M, & Kipps C (2012). Hydration Strategies of Runners in the London Marathon. Clinical Journal of Sport Medicine PMID: 22246343


Nicole Cattano said...

Kyle-Great Post! This topic is certainly one that is well explored and discussed here at our school. Did the article talk about any gender disparities? Previous literature and clinical practice has often sited how females are so much more susceptible to EAH than males.

I think that this will require a total culture shift in how we think. Media and marketing certainly has planted the myths that we are not drinking enough if we only drink when we are thirsty, that we should drink enough fluid so that our urine is clear, or that we must carry water bottles around at all times.

I recently when to my local YMCA and there was a wellness activity that females should consume 82 oz of water, and males should consume 118 oz, and they would receive an "award." This is CRAZY! The issue is that most people do not associate consume with the water that we eat in our food either.

I have no idea how we change this behavior, and would love to hear others' thoughts on this.

Kyle said...


Interesting question, and with good reason. The results of this study are pretty limited with respect to gender. The did report that the respondents were 151 (69.9%) male and 66 (30.4%) female. The only other time that gender is addressed is when the author states that there was a trend toward drinking greater than 3.5L of water and slower finishing times, but that there was no difference between men and women. Other than that the idea of gender differences is not discussed.

I think what you saw at your local YMCA is a great example of the misconceptions out there. In my opinion, there needs to be a much more massive educaiton campaign to get the point across. A very interesting point made in this study reported that 70% "read information about fluid intake.." but when it came to the knowledge of drinking strategies only 25% identified "drinking to thirst" as the most important factor despite this being the recommendation of International EAH Consensus Developement Conference and the International Marathon Medical Directors Association.

Perhaps it isn't runners aren't exposed enough, but how the information is presented to interpreted. I for one would find it very interesting to see how the fluid intake information was presented on the offical race magazine. What does everyone else think? Might this be a communication problem rather than a information accessibility problem?

Kirsten Miner said...

Assuming that the participants of this study are highly trained for marathons and that training and long distance running are not new concepts I find it surprising that they are not more informed about nutritional importance of hydration. It would be interesting to see the wording used and the length of the information in the race magazine. I for one prefer to read articles that are short and have pictures or charts and are not scientifically written. If the goal is to make the public more informed then that information not only has to be prominent and accessible but also easy for the lay person to understand. Was there any distinction between drinking water to hydrate instead of various sports drinks? Water is the best way to hydrate but with all the advertisements for Gatorade and Powerade and the different subsystems of those I wonder how that is affecting the hydration plans of these runners.

Kyle said...

Hi Kirsten,

I too would like to see the example of what was use in the race magazine. I think that might be the key to explaining some of these numbers. Whenever you put an insert in with other advertisements and information you run the risk of your insert being skipped over. Perhaps there was something else in the magazine that caught people attention taking it away from the insert.

The only mention of sports drinks versus water was that both were available, and some marathon participants specifically planned to drink at either all, one of the sports drink stations, or a variation thereof. No reasoning behind what caused them to make that decision was not reported. I would be interested, as I said above, to get into the idea of advertisements and to try and understand if that played a role in this. Great thoughts! Thank you!

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