CHAPTER 4 HYDRATION BELIEFS AND PRACTICES AMONG RUNNERS IN A MIDWEST MARATHON Lynne Stamey, Kay Wolf, Diane Habash, Laura Harris, Christopher Taylor, Jenna Bell- Wilson Abstract Over the last 30 years, the profile of a marathon runner has changed; novice runners (typically > 4 hour completion) have joined in a race once associated with only the elite. With the increase in novice and slower runners, reported cases of exercise- associated hyponatremia (serum sodium concentration below 135 mEq/L ) during marathons have increased and drawn attention from medical professionals, researchers, racers and event coordinators 1-7. The purpose of this study was to measure the differences between experienced and inexperienced marathon runners on their practices and beliefs regarding fluid intake during marathons. Results show there is no difference between the hydration beliefs and practices of experienced and inexperienced marathon runners, nor is there a consensus among runners on proper hydration technique. Based on subject responses, runners have developed inconsistencies in their hydration beliefs and practices, intertwining information on hydration from new research with outdated information. Key words: Hydration, Hyponatremia, Fluid intake, Marathon, Runners Introduction Fluid recommendations for athletes have wavered over the years. In 1996, the American College of Sports Medicine (ACSM) published a position statement for Exercise and Fluid Replacement 17 to promote euhydration among athletes during events and training. ACSM recommended that during exercise, athletes should consume 150 ml - 300 ml every 15 to 20 minutes (600 ml – 1200 ml per hour) to replace the fluid lost through sweat, or consume “the maximum amount that can be tolerated” to prevent dehydration. The belief was that thirst was not an accurate indicator of fluid need and by the time an athlete became thirsty he was already dehydrated. The statement addressed hyponatremia by recommending sodium containing fluids to replace the sodium lost through sweat. Since the 1996 release, studies have shown that while sodium supplementation may decrease the severity of exercise-associated hyponatremia, it is not prevented if the athlete is over-consuming water in response to sweat losses18-20. In 2002, the International Marathon Medical Directors Association (IMMDA) published an advisory statement on the Guidelines for Fluid Replacement During Marathon Running 21 in an attempt to correct the belief that runners should “drink as much as possible” for optimal performance. Contradicting ACSM guidelines of consuming between 600 ml – 1200 ml per hour17, IMMDA recommended drinking ad libitum, but no more than 400 ml – 800 ml per hour 22, 23. Due to differences among individual athletes, IMMDA deemed it is unsafe to give a blanket statement on fluid intake. In addition, IMMDA provided anecdotal evidence by interviewing elite-athletes who stated they consumed minimal fluid during marathon events (~200 ml/hour) due to difficulty ingesting larger volumes while running at a faster speed and higher intensity. The following year, USA Track & Field (USATF) 24 issued an advisory statement announcing the adoption of the new IMMDA guidelines. USATF also discussed the importance of calculating an individual sweat rate for “optimal hydration”, providing instructions for calculation. The 1st International Exercise-Associated Hyponatremia Consensus Development Conference (CDC) 25 was held in 2005 with the primary goal of reviewing current research to determine the etiology of exercise-associated hyponatremia. The secondary goal was to provide guidelines for its prevention. CDC issued a position statement25 stressing the importance of thirst as the primary determinant of fluid intake and recommending the USATF method of calculating sweat rate. The same year, ACSM convened to conduct a roundtable discussion and review current research on hydration and physical activity26, issuing several evidence-based consensus statements as a result. While no specific recommendations were made, ACSM discussed the importance of education for both professional and recreational athletes in preventing exercise-associated hyponatremia. ACSM suggested an individualized approach to fluid intake, and identified evidence-based research which shows that each athlete should calculate his or her sweat rate so that fluid intake never exceeds sweat losses. In 2006, IMMDA 27 again revised their guidelines stating runners should drink only when thirsty, and provided a chart showing recommended fluid intake to pace or time. IMMDA emphasized that the motivated athlete should calculate an individual sweat rate to determine fluid intake for prevention of both exercise-associated hyponatremia and dehydration. In 2007, ACSM issued a new position statement 28, emphasizing the individualized approach to hydration. For runners who have not calculated their sweat rate, ACSM recommended drinking ad libitum, but no more than 0.4 – 0.8 L/hr-1 (smaller amounts for low body weight, more for larger body weight). For the first time, the hydration guidelines from ACSM and IMMDA are close in agreement. Both disregard the “one size fits all” fluid intake recommendations of the past, and instead emphasize the importance of letting thirst dictate fluid intake. Although ACSM placed more emphasis on the importance of sweat rate calculation28, both ACSM and IMMDA agree that hydration is based on the individual, and calculating individual sweat rates for proper hydration during a marathon can prevent exercise-associated hyponatremia and dehydration25, 28. Marathon directors and organizers are aware of the dangers of hyponatremia and have access to the current recommendations from the aforementioned organizations; however the knowledge and behavior of the marathon participant is unknown. Data is lacking on hydration beliefs and practices of marathon runners, and whether they have knowledge of the current recommendations for fluid intake. Gauging the beliefs and practices of marathon runners may provide valuable information on where to focus future education efforts. The purpose of this study is to assess the hydration practices and beliefs of marathon participants and measure the differences between experienced and inexperienced marathon runners. Methods A three part, thirty-one question survey was e-mailed to all registered participants of the 2006 Columbus Marathon with a valid e-mail address. Part I and Part II of the survey used a Likert Scale to measure beliefs and practices of the subjects54. Respondents were asked to rank their level of agreement with each statement ranging from one (“Strongly Agree”) to four (“Strongly Disagree”). Part I of the survey included twelve questions to determine the hydration beliefs of the subjects. Part II of the survey asked eleven questions to determine the hydration practices of the subjects. Part III of the survey included six close-ended questions regarding demographics (age, gender), individual information on marathon times, number of completions, hydration resources, and whether the subjects trained individually or with a group. Subject Selection Subjects included registered participants over the age of 18 who completed the 2006 Columbus Marathon, including all runners, walkers and wheelchair participants (n=4,097). All participants who completed the survey in its entirety have been included in the results (n=1,185). Calculating Scores A four point scale was used for calculating mean scores. An answer of 3 or 4 indicated the question was answered correctly. An answer of 1 or 2 indicated the question was answered incorrectly. The higher the mean score, the more accurate the response. Items 1-12 were used to compute the “belief score”. The maximum score possible is 48 (412), and the minimum score possible is 12 (112). Statements 15-25 were used to compute the “practices score”. The maximum score possible is 44 (411) and the minimum possible score is 11 (111). To allow scores to be computed accurately, several questions were reverse coded for calculation. For these questions only, an answer of 1 became 4; an answer of 2 became 3; an answer of 3 became 2; and an answer of 4 became 1. Statistical Analysis T-tests of independent samples were used to compare beliefs and practices with descriptive characteristics. Spearman’s correlation determined the relationship between completion time and beliefs or practices. Pearson’s correlation was used when calculating the relationship between demographics (age, gender) and beliefs or practices. Results An internet survey was sent to 4,097 participants of the 2006 Columbus Marathon via e-mail. A total of 288 e-mails were undeliverable, resulting in 3,809 delivered e- mails. The number of e-mails opened by recipients was 2,247 (58.9% of delivered). The number of surveys received back from participants was 1,270 (33.3% of delivered, 56.5% of opened). Respondents who returned incomplete questionnaires were excluded (n=85, 6.7% of total returned), resulting in a total of 1,185 (93% of returned) completed survey responses. There were 673 male (57%) and 562 female (47%), 623 experienced runners (53%) and 562 inexperienced runners (47%). Age of the respondents ranged from 18 to 76. Results of the survey are reported in Tables 4.1 and 4.2 Table 4.1: Beliefs of marathon runners (n=1,185) Strongly Strongly Agree Agree Disagree Disagree BELIEFS % % % % Each marathon runner should consume a set amount of water per hour, depending on their body weight. 10.0 38.8 46.9 4.2 * Every person has different fluid needs during a marathon. 46.8 51.9 1.4 0.0 My performance will suffer if I finish a marathon slightly dehydrated (slight decrease in total body weight). 14.9 40.3 41.5 3.4 If I am feeling thirsty, it means I am already dehydrated. 34.4 44.1 19.5 1.9 Drinking before I am thirsty will prevent dehydration. 24.6 62.4 11.8 1.1 It is better for my performance to drink more fluid than I lose during a marathon. 3.1 26.2 60.6 10.0 *It is better for my performance to drink a sports drink instead of water when running a marathon. 13.8 45.6 37.0 3.7 The longer it takes me to complete a marathon, the more fluids I should drink. 12.8 52.7 30.8 3.7 My performance will suffer more if I drink too much than if I drink too little. 8.4 43.5 44.9 3.3 Regardless of the temperature on race day, I should drink the same amount of fluid for every race. 1.4 7.6 53.2 37.8 Drinking a sports drink instead of water will prevent me from being over-hydrated. 1.0 15.9 67.2 15.9 I should continue drinking fluid after the marathon, even if I am not thirsty. 27.1 61.5 11.1 0.3 * indicates question was reverse coded for analysis Table 4.2: Practices of marathon runners (n=1,185) Strongly Strongly Agree Agree Disagree Disagree PRACTICES % % % % *I drink fluid only when I am thirsty 1.2 13.4 71.3 14.1 *On a warm or hot race day, I tend to drink more fluids 41.2 57.1 1.5 0.2 *I weigh myself before and after a training day run to check my fluid status. 5.3 16.6 49.5 28.6 *I weigh myself before and after a race to check my fluid status 3.5 13.4 53.2 29.9 I try to drink before I am thirsty. 18.2 71.6 10.1 0.1 I try to replace 100% of the fluid lost through sweat and urination. 8.9 44.8 44.0 2.4 *I change how much I drink based on my thirst 7.9 64.7 25.8 1.5 I drink at every water station, whether I'm thirsty or not 11.8 33.1 43.4 11.7 *I have calculated my sweat rate 1.4 5.1 50.1 43.5 *I use my sweat rate calculation to determine how much I drink during a marathon. 0.7 5.1 50.5 43.7 *I use the same drinking practices during training as I do on race day. 11.6 42.3 39.2 6.9 * indicates question was reverse coded for analysis Experienced runners (30.5 ± 3.4) had a significantly higher belief score than inexperienced runners (30.0 ± 3.0, p=<0.004), however there was no significant difference between the practices of experienced (25 2.9) and inexperienced marathon runners (24.7 2.8, p=<0.088). There was a significant negative correlation between beliefs and completion time (r = -0.081, p=<0.005), but there was no relationship between practices and completion time of runners (r= -0.013, p=<0.651). No relationship was found between the beliefs of runners who participate in an organized running group (30.3 3.0) and runners who do not (30.3 3.1, p=<0.566), nor is their a relationship between the practices of runners who participate in an organized running group (24.9 2.8) and the practices of runners who do not (24.8 2.9, p=<0.499), There was a significant difference in the beliefs of male (30.7 3.1) versus female runners (29.7 3.0, p=<0.0001), but no differences between the practices of male (24.9 2.0) and female runners (24.7 2.8, p=<0.346). Finally, a significant relationship was observed between the beliefs and age of marathon runners (r=0.125, p=<0.0001) as well as the practices and age of marathon runners (r=0.115, p=<0.0001). The most frequent sources of hydration information were coach (67%), friends (44.8%) and the internet (37%). This is consistent with runners who were experienced, inexperienced; runners who do not participate in a training group; and runners with completion times above and below four hours. Runners who train with a group use coaches (68%) most frequently for hydration information, followed by friends (53%) and running magazines (40.8%). The resources least frequented for hydration information for all runners are IMMDA (0.7%), USATF (4.1%) and GSSI (4.6%). Results are reported in Table 4.3. Table 4.3: Sources of hydration information (n=1,185) Train with a Group Completion time Sources of Total Inexperienced Experienced Yes No <4 hrs >4 hrs Information % % % % % % % USATF 4.1 3.4 4.8 5.7 3.5 4.6 3.5 ACSM 5.2 4.1 6.3 5.7 5.0 5.6 4.7 IMMDA 0.7 0.2 1.1 1.1 0.5 0.7 0.6 GSSI 4.6 3.9 5.2 5.9 4.0 5.5 3.3 Magazine 17.7 17.7 17.6 40.8 7.9 15.9 20.4 Coach 67.1 59.9 73.8 68.0 66.7 70.2 62.0 Internet 37.0 36.0 37.8 29.5 40.1 37.6 36.0 Friend 44.8 47.9 42.0 53.0 41.3 41.6 49.3 Other 27.6 27.7 27.4 24.6 28.8 26.5 29.1 USATF = USA Track & Field; ACSM=American College of Sports Medicine; IMMDA=International Marathon Medical Directors Association; GSSI=Gatorade Sports Science Institute Discussion The main factor contributing to exercise-associated hyponatremia is intake of water and sports drinks in excess of fluid losses (sweat, urine)55. To reduce the incidence of exercise-hyponatremia, experts have recommended that endurance athletes drink ad libitum, and use their calculated sweat rate to individualize fluid needs24-26, 55. IMMDA25, USATF24 and CDC25, 55 further suggest using thirst as an indicator of fluid consumptions. Subject’s responses in the present study contradict these recommendations. A majority of respondents (89.8%) try to drink before they are thirsty; with 87% stating that drinking before they are thirsty will prevent dehydration and 78.5% believing if they are feeling thirsty, they are already dehydrated. Only 14.6% of respondents stated they do not drink until they are thirsty. While the recommendations for fluid intake post-exercise vary slightly, none recommend excessive drinking. ACSM26 and IMMDA25 suggest that normal consumption of food and beverage with higher sodium levels (pretzels, broth) post- exercise will bring the body back into euhydration. USATF24 suggests the goal of post- exercise hydration is to replenish fluids lost based on sweat rate calculations. However, 85.6% of the runners surveyed believe they should continue to drink after a marathon, even if they are not thirsty. Hyponatremia can develop post-race due to aggressive overhydration53 in an attempt to replenish fluids, especially if fluid losses are unknown. In 2003, USATF24 recommended calculating individual sweat rates for prevention of hyponatremia and dehydration. Since then, sweat rate calculation has been endorsed by IMMDA25, 27, ACSM26 and CDC55, as well as several sports nutrition companies such as PowerBar56 and Gatorade57. Contrary to these endorsements, only 6.5% of respondents have calculated their sweat rate, and only 5.8% of runners use their sweat rate calculation to determine fluid intake on race day. In addition, only 22% of respondents weigh themselves before and after a training run, and 17% on race day to check their hydration status. Perhaps runners do not calculate their sweat rate due to the cumbersome nature of the process. To calculate sweat rate, runners must weight themselves nude prior to a run, track and measure fluid intake during a one hour run, void, weigh themselves nude post run, subtract post-weight from pre-weight, convert to ounces, and add to fluid consumed. This calculation should be completed in several different environmental conditions for an accurate sweat rate calculation. The survey revealed several questions where the respondent’s beliefs and practices were divided, indicating that half of the runners surveyed have improper hydration techniques. When asked about performance and hydration, 48.2% of respondents did not believe their performance would suffer more if they drank too much than if they drank too little, while 55.2% believe their performance will suffer if they finish a marathon slightly dehydrated. This is inconsistent with the practices of elite marathon runners, most of whom finish the race slightly dehydrated15, 21. Further increasing the risk of hyponatremia is the practice of drinking at every water station (44.9%) whether they are thirsty or not. Of the 25 questions on hydration beliefs and practices, a majority of respondents answered only three questions consistent with IMMDA25, 27, ACSM26 and CDC55recommendations25-27, 55. Subjects (98.6%) believe that every runner has different fluid needs during a marathon, 98.3% drink more fluids on hot or warm days and 91% do not agree with the statement that they should drink the same amount of fluid regardless of the temperature. Summary The data reveal that there is not a difference between the hydration beliefs and practices among experienced and inexperienced marathon runners, nor is there a consensus among runners on proper hydration technique. According to the results, runners have developed inconsistencies in their hydration beliefs and practices. There is a consensus among researchers6, 12, 32, 33, 58 that education is the key to prevent hyponatremia. The results from this research show that a majority of marathon runners (67.1%) look to their coaches for hydration information. Educating coaches appears to be paramount in promoting proper hydration techniques to athletes. Additionally, researchers have shown that education provided by marathon directors and organizers can reduce the number of events of exercise-associated hyponatremia33, 45. While organizations such as ACSM, IMMDA and CDC are approaching agreement in their hydration position statements, each publish slightly different hydration recommendations. Perhaps runners need to be presented with one clear consolidated hydration technique to prevent hyponatremia and dehydration, endorsed by all three organizations. Many of the runners surveyed (17.7%) use magazines such as Runner’s World as the source for hydration information. These magazines publish articles with updated information from IMMDA and ACSM59, 60. It is unclear as to whether receiving multiple versions of hydration techniques is confusing to the reader. Previous communications which stressed the importance of consuming “the maximum amount that can be tolerated”17 have created a lasting impression with marathon runners. These legacy beliefs are still maintained by many athletes. Future campaigns will likely need to address this issue directly. Introducing “new” hydration recommendations endorsed by the top three hydration organizations, ACSM, IMMDA and CDC, may strengthen the message of proper hydration techniques to coaches and athletes, reducing or preventing future cases of exercise-associated hyponatremia.