Hydration knowledge and practices of long distance runners in the South African National Defence Force

English: Endurance exercise has recently become more popular, but requires optimal hydration to ensure peak performance. The human body regulates fluid homeostasis as long as food and fluids are available. As soon as an athlete starts to train, muscle exertion and environmental factors challenge the ability of the human body to regulate fluid homeostasis. A weight loss of more than two percent during exercise has been linked to changes in haemorheology, metabolic dysregulation, heat intolerance, cardiovascular strain, and the subsequent inability to maintain exercise workload. In this study the hydration knowledge and practices of long distance runners in the South African National Defence Force was determined in relation to current hydration recommendations. The study followed a descriptive, observational design, using a self-reporting questionnaire and anthropometric measurements as data collection techniques. Of the 144 participants included in the study, the majority was black (40.5%) males (80.5%), mostly from the Western Cape (47.7%), who works as operators (51.9%). Participants had a mean age of 40 (±8.636 SD) years. According to the body mass index (BMI), four (3.2%) participants were underweight, 36.0% overweight/obese and 60.8% had a normal weigh, with no significant difference between the mean BMI of half and full marathon (p=0.0601). With more than a third of athletes being overweight/obese, athletes need to be informed regarding the health implications of being overweight or obese, as well as the impact of overweight and obesity during endurance exercise on performance. Reported race experience, ranged between 13 and 365 months. A mean weight loss of 0.002 kg (±0.404 SD) was recorded between registration and pre-race, with the largest weight loss being 0.8 kg and the most weight gained 3.5 kg. Nearly half (42%, n=55) of participants for whom body weight was measured before and after the race lost 2% or more of their body weight during the race. A maximum weight loss of 4.2 kg was measured during the race, which equalled a body weight loss of 6.36%. This put the athletes at risk for serious health risks and implicates that athletes need to be educated regarding the dangers of fluid losses during activity. With regard to hydration knowledge, 66.0% of participants obtain hydration knowledge mainly from reading books and magazines and 94 (65.3%) participants indicated that they read labels on sports drinks, focussing mostly on carbohydrate level. Athletes need to be counselled to focus on electrolyte levels as well. Although the majority (73.8%) of participants knew that fluid influences performance, 20 (13.9%) were not able to indicate why weight loss occurs during marathon participation and 38.9% were uncertain whether urine colour influences physical performance. Although most participants had a reasonable good general knowledge regarding hydration, training is needed in important areas such as the effect fluid have on performance and how to assess hydration status using urine colour and weight change during training and competitions. Alarmingly 11.1% of participants were not able to report symptoms of dehydration, which is important to prevent heat-related illnesses. Athletes should be able to identify dehydration as well as over hydration early, understand the implications, and be equipped to restore hydration status in order to optimize performance. With regard to hydration practices nine participants (6.3%) indicated that they do not consume extra fluids before, during or after a race, which is a cause for concern considering the health risks associated with dehydration. Athletes need to be aware of the implication of not consuming sufficient amounts of fluids when participating in endurance events. Fourty one percent participants consumed extra fluids at least four hours before the race. For athletes participating in the half marathon, mean fluid intake was significantly higher than for the full marathon. There was however no significant difference in fluid intake per kilogram body weight between the half; and full marathon. Participants preferred energy drinks (32.6%) before a race and water during (28.5%) and after (21.5%) a race. Most participants (78.5%) relied solely on fluids provided by the race organisers and few (13.2%) carried fluids with them. The amount of fluid consumed depended mostly on environmental conditions (71.1%), with only 13.6% participants consuming more fluids due to dehydration cues. Most participants (61.8%) reported to drink according to thirst rather than to maintain weight or according to schedule and more than half (54.8%) reported that they never dehydrate during a race. More attention should be given to educate runners on how to monitor hydration status, emphasizing that thirst is not the only hydration cue and is not sufficient to prevent dehydration. Athletes should be taught how to use different techniques to assess hydration status and need to learn how to develop an appropriate individualized rehydration strategy comprising the amount as well as time of fluid intake.