Beliefs about hydration and physiology drive drinking behaviours in runners
Winger JM, Dugas JP, Dugas LR. Br J Sports Med. 2011 Jun;45(8):646-9. Epub 2010 Sep 28.
It is currently estimated that between 0.3 to 13% of marathon runners finish the race with evidence of exercise-associated hyponatraemia (EAH), a condition caused primarily by an excessive intake of hypotonic fluid. It may be possible to reduce the risk of EAH if we can introduce education programs for marathon runners but more research is needed to understand the beliefs among marathon runners. Therefore, Winger et al assessed the beliefs about fluid replacement among marathon runners and whether these beliefs are reflected in hydration behaviors. Participants (over 18 years of age) in three races held in the fall of 2009 (midwestern United States) were recruited via advertising at the event registration, through flyers given out on the days of races, and by links from the race websites (therefore, it is possible non-runners participated). The survey was completed online and asked about drinking behaviors during running. Data was analyzed for 107 runners (typically in their late thirties or early forties) and revealed that most runners drink a combination of water and sports drinks (57%) and only when thirsty (56%). Nine percent of runners drink as much as possible during the race. Marathon runners that drank on a schedule tended to be older, more experienced (based on years running and number of previous races), and faster than those drinking when thirsty. Runners noted that “personal experience” was the most important source of hydration and drinking advice rather than national and international scientific organizations, coaches, or race organizers. Eighteen percent of respondents were not familiar with EAH. The authors note that runners had a poor understanding of the physiological consequences of hydration behaviors that frequently reflected messages of advertising in spite of runners reporting a lack of corporate marketing influence.
This study is important for understanding the misconceptions and behaviors of marathon runners. SMR had another post a few months ago that highlights that marathon runners “lacked concern for injury or hyponatremia, and were not using methods of hydration assessment.” This study provides further support that the sports medicine community should reach out to marathons and promote education programs to raise awareness about managing injuries and preventing EAH. The authors of the current study “propose that a more appropriate manner to address the issue of overhydration in mass running events is to treat the issue as one of public health within the realm of sports medicine and science.” It will be helpful to see more research in larger cohorts that question people at the marathon (to ensure they are participants), to monitor hydration practices during the run, and to assess the effectiveness of education program. This could be a great opportunity for the sports medicine community to reach out to a larger population and help prevent injuries and illnesses. Do you feel it is time for the sports medicine community to promote education programs for marathon runners? Are you aware of any education programs for marathon runners in your community?
Written by: Jeffrey Driban
Reviewed by: Kyle Harris
Winger JM, Dugas JP, & Dugas LR (2011). Beliefs about hydration and physiology drive drinking behaviours in runners. British Journal of Sports Medicine, 45 (8), 646-9 PMID: 20876587
I believe it is time for athletic trainers to promote education programs for the marathon community. I believe they are not educated well enough on this topic and we could save a lot of people if we spread the importance of properly hydrating.
I am confused. The paper notes that faster more experienced runners drink, but at the same time suggests that drinking too much is the problem. Should one drink only when thirsty or not? Hyponatremia is associated with drinking too much, resulting in low sodium levels in the blood. Is the answer that one should drink sports drinks? Or eat salty foods before a race?
Hi Timothy: It's a bit of a Goldilocks phenomenon. Drinking when thirsty is problematic b/c at that point you are already somewhat dehydrated. Drinking too much is problematic as well. It's important to find a middle ground. Faster runners tend to drink more than just when they are thirsty. It's not clear if they are drinking an optimal amount or if this is the group we need to talk to about being careful to not drink too much.