Hydration Strategies Research Articles

Dehydration and rehydration in competative sport

Dehydration, if sufficiently severe, impairs both physical and mental performance, and performance decrements are greater in hot environments and in long-lasting exercise. Athletes should begin exercise well hydrated and should drink during exercise to limit water and salt deficits. Many athletes are dehydrated to some degree when they begin exercise. During exercise, most drink less than their sweat losses, some drink too much and a few develop hyponatraemia. Athletes should learn to assess their hydration needs and develop a personalized hydration strategy that takes account of exercise, environment and individual needs. Pre-exercise hydration status can be assessed from urine frequency and volume, with additional information from urine color, specific gravity or osmolality. Changes in hydration status during exercise can be estimated from the change in body mass: sweat rate can be estimated if fluid intake and urinary losses are also measured. Sweat salt losses can be determined by collection and analysis of sweat samples. An appropriate, individualized drinking strategy will take account of pre-exercise hydration status and of fluid, electrolyte and substrate needs before, during and after a period of exercise.

Development of hydration strategies to optimize performance for athletes in high‐intensity sports and in sports with repeated intense efforts

Hypohydration - if sufficiently severe - adversely affects athletic performance and poses a risk to health. Strength and power events are generally less affected than endurance events, but performance in team sports that involve repeated intense efforts will be impaired. Mild hypohydration is not harmful, but many athletes begin exercise already hypohydrated. Athletes are encouraged to begin exercise well hydrated and - where opportunities exist - to consume fluid during exercise to limit water and salt deficits. In high-intensity efforts, there is no need, and may be no opportunity, to drink during competition. Most team sports players do not drink enough to match sweat losses, but some drink too much and a few may develop hyponatremia because of excessive fluid intake. Athletes should assess their hydration status and develop a personalized hydration strategy that takes account of exercise, environment and individual needs. Pre-exercise hydration status can be assessed from urine markers. Short-term changes in hydration can be estimated from the change in body mass. Sweat salt losses can be determined by collection and analysis of sweat samples. An appropriate drinking strategy will take account of pre-exercise hydration status and of fluid, electrolyte and substrate needs before, during and after exercise.

Hydration strategies for exercise performance in hot environment

Maintaining fluid balance, or hydration, is an important factor in preserving various body functions and supporting exercise performance in hot environment. During exercise, fluids are lost, mainly through sweating (some...

Arginine Vasopressin, Fluid Balance and Exercise

The ability of the human body to regulate plasma osmolality (POsm) within a very narrow and well defined physiological range underscores the vital importance of preserving water and sodium balance at rest and during exercise. The principle endocrine regulator of whole body fluid homeostasis is the posterior pituitary hormone, arginine vasopressin (AVP). Inappropriate AVP secretion may perpetuate either slow or rapid violation of these biological boundaries, thereby promoting pathophysiology, morbidity and occasional mortality. In the resting state, AVP secretion is primarily regulated by changes in POsm (osmotic regulation). The osmotic regulation of AVP secretion during exercise, however, may possibly be enhanced or overridden by many potential non-osmotic factors concurrently stimulated during physical activity, particularly during competition. The prevalence of these highly volatile non-osmotic AVP stimuli during strenuous or prolonged physical activity may reflect a teleological mechanism to promote water conservation during exercise. However, non-osmotic AVP secretion, combined with high fluid availability plus sustained fluid intake (exceeding fluid output), has been hypothesized to lead to an increase in both the incidence and related deaths from exercise-associated hyponatraemia (EAH) in lay and military populations. Inappropriately, high plasma AVP concentrations ([AVP](p)) associated with low blood sodium concentrations facilitate fluid retention and sodium loss, thereby possibly reconciling both the water intoxication and sodium loss theories of hyponatraemia that are currently under debate. Therefore, given the potential for a variety of exercise-induced non-osmotic stimuli for AVP secretion, hydration strategies must be flexible, individualized and open to change during competitive events to prevent the occurrence of rare, but life-threatening, EAH. This review focuses on the potential osmotic and non-osmotic stimuli to AVP secretion that may affect fluid homeostasis during physical activity. Recent laboratory and field data support: (i) stimulatory effects of exercise intensity and duration on [AVP](p); (ii) possible relationships between changes in POsm with changes in both sweat and urinary osmolality; (iii) alterations in the AVP osmoregulatory set-point by sex steroid hormones; (iv) differences in [AVP](p) in trained versus untrained athletes; and (v) potential inter-relationships between AVP and classical (aldosterone, atrial natriuretic peptide) and non-classical (oxytocin, interleukin-6) endocrine mediators. The review concludes with a hypothesis on how sustained fluid intakes beyond the capacity for fluid loss might possibly facilitate the development of hyponatraemia if exercise-induced non-osmotic stimuli override 'normal' osmotic suppression of AVP when hypo-osmolality exists.

Efeito do nível de condicionamento físico e da hidratação oral sobre a homeostase hídrica em exercício aeróbico

Objetivou-se avaliar a influência do nível de condicionamento físico no estado de hidratação e a eficácia do consumo de 3mL de água/kg de peso corporal para manter a eu-hidratação de indivíduos atletas ou ativos saudáveis. Foram avaliados 15 atletas {VO2máx 68 ± 5,4mL (kg.min)-1} e 15 sujeitos ativos {VO2máx 50,3 ± 6,3mL(kg.min)-1} saudáveis do sexo masculino. O estado de hidratação foi diagnosticado por meio do monitoramento do peso corporal, da gravidade específica da urina e do hematócrito durante 80 minutos de corrida em esteira. Foram consumidos, durante a atividade, 3mL de água/kg de peso corporal. As condições ambientais do teste foram de 21,9 ± 1,5°C e 89,2 ± 5,6% de umidade relativa do ar (URA) para os atletas e 21,8 ± 1,6°C e 93,2 ± 3,5% URA para os ativos. O percentual médio de desidratação e a perda de peso relativa foram significativamente maiores nos atletas (2,15 ± 0,7% e 1,3 ± 0,5kg), comparados aos ativos (1,03 ± 0,7% e 0,74 ± 0,43kg), respectivamente. A gravidade específica da urina aumentou significativamente apenas nos atletas, enquanto o hematócrito não variou significativamente entre os grupos. Considerando as condições de teste, conclui-se que o nível de condicionamento mais alto permitiu menor estado de hidratação e que, embora a perda hídrica não tenha atingido níveis críticos, a estratégia de hidratação utilizada (3mL de água/kg de peso corporal) não foi suficiente para manter os avaliados completamente eu-hidratados.

The effects of different hydration strategies before endovascular treatments to the renal function of the arteriosclerosis obliterans patients

To compare the efficacies of different hydration strategies in protecting the renal function of the arteriosclerosis obliterans (ASO) patients undergoing endovascular treatments. 40 patients who underwent endovascular treatments for arteriosclerosis obliterans of lower extremities in the Vascular Surgery Department of PLA Hospital from January 2009 to October 2009 were divided into normal (serum creatinine < or = 110 micromol/L) and abnormal (serum creatine > 110 micromol/L) groups according to their baseline serum concentration of creatinine before treatments. Each group was treated by different hydration strategies 12 h before procedures. Changes of serum creatinine and creatinine clearance were measured 6, 24, 48 h after procedures to evaluate the changes of renal function and the effects of different hydration strategies. No contrast-induced nephropathy (CIN) was observed among the 40 patients. There are significant differences between normal saline hydration group and control group in the changes of serum creatinine and creatinine clearance 24 h and 48 h after exposure to contrast medium for the normal renal function patients (P < 0.05). For the patients pre-existing renal dysfunction, no significant difference was found between Sodium Bicarbonate + Saline group and Saline group in the changes of Scr and Ccr 6, 24, 48 h after exposure to contrast medium (P > 0.05). Sodium chloride provides a good efficacy for preventing the adverse effect of contrast medium to the renal function of the ASO patients. For the patients pre-existing renal dysfunction, Combination hydration with sodium bicarbonate is not more effective than normal saline alone in preventing contrast-induced renal dysfunction.

Making the Weight: A Case Study From Professional Boxing

Professional boxing is a combat sport categorized into a series of weight classes. Given the sport's underpinning culture, boxers' typical approach to "making weight" is usually via severe acute and/or chronic energy restriction and dehydration. Such practices have implications for physical performance and also carry health risks. This article provides a case-study account outlining a more structured and gradual approach to helping a professional male boxer make weight for the 59-kg superfeatherweight division. Over a 12-week period, the client athlete adhered to a daily diet approximately equivalent to his resting metabolic rate (6-7 MJ; 40% carbohydrate, 38% protein, 22% fat). Average body-mass loss was 0.9 + or - 0.4 kg/wk, equating to a total loss of 9.4 kg. This weight loss resulted in a decrease in percent body fat from 12.1% to 7.0%. In the 30 hr between weigh-in and competition, the client consumed a high-carbohydrate diet (12 g/kg body mass) supported by appropriate hydration strategies and subsequently entered the ring at a fighting weight of 63.2 kg. This nutritional strategy represented a major change in the client's habitual weight-making practices and did not rely on any form of intended dehydration during the training period or before weighing in. The intervention demonstrates that a more gradual approach to making weight in professional boxing can be successfully achieved via a combination of restricted energy intake and increased energy expenditure, providing there is willingness on the part of the athlete and coaches involved to adopt novel practices.

Fatigue management in the preparation of Olympic athletes

Fatigue is often a consequence of physical training and the effective management of fatigue by the coach and athlete is essential in optimizing adaptation and performance. In this paper, we explore a range of practical and contemporary methods of fatigue management for Olympic athletes. We assesses the scientific merit of methods for monitoring fatigue, including self-assessment of training load, self-scored questionnaires, and the usefulness of saliva and blood diagnostic markers for indicating fatigued and under-recovered athletes, effective nutrition and hydration strategies for optimizing recovery and short-term recovery methods. We conclude that well-accepted methods such as sufficient nutrition, hydration, and rest appear to be the most effective strategies for optimizing recovery in Olympic athletes.

Sodium bicarbonate-based hydration prevents contrast-induced nephropathy: a meta-analysis

BackgroundContrast-induced nephropathy is the leading cause of in-hospital acute renal failure. This side effect of contrast agents leads to increased morbidity, mortality, and health costs. Ensuring adequate hydration prior to contrast exposure is highly effective at preventing this complication, although the optimal hydration strategy to prevent contrast-induced nephropathy still remains an unresolved issue. Former meta-analyses and several recent studies have shown conflicting results regarding the protective effect of sodium bicarbonate. The objective of this study was to assess the effectiveness of normal saline versus sodium bicarbonate for prevention of contrast-induced nephropathy.MethodsThe study searched MEDLINE, EMBASE, Cochrane databases, International Pharmaceutical s database, ISI Web of Science (until 15 December 2008), and conference proceedings for randomized controlled trials that compared normal saline with sodium bicarbonate-based hydration regimen regarding contrast-induced nephropathy. Random-effects models were used to calculate summary odds ratios.ResultsA total of 17 trials including 2,633 subjects were pooled. Pre-procedural hydration with sodium bicarbonate was associated with a significant decrease in the rate of contrast-induced nephropathy (odds ratios 0.52; 95% confidence interval 0.34–0.80, P = 0.003). Number needed to treat to prevent one case of contrast-induced nephropathy was 16 (95% confidence interval 10–34). No significant differences in the rates of post-procedure hemodialysis (P = 0.20) or death (P = 0.53) was observed.ConclusionSodium bicarbonate-based hydration was found to be superior to normal saline in prevention of contrast-induced nephropathy in this updated meta-analysis.

Initial Hydration Status And Fluid Balance During Exercise Of Coaches And Fitness Trainers

Current hydration guidelines emphasize the need to personalize fluid replacement strategies due to the extent variation on sweat rates between individuals. Also, it is recognized the importance of begin exercise well hydrated. Coaches and fitness trainers are key advising athletes and fitness enthusiast about having adequate hydration habits during exercise. PURPOSE: To determine initial hydration status and fluid balance during an exercise bout on coaches and fitness trainers who were participating in a sports science course. METHODS: Data were collected from 217 subjects (131 males and 86 females; age 30.6 + 8.9 years) during one 45-60 min exercise bout. Data were obtained during 4 separate sessions carried out at morning with a mean WBGT in the range of 17.9-23.8°C. Exercise bout consisted of intermittent exercise that combines martial arts and kickboxing (Body Combat). Subjects collected a urine sample from their first void of the morning and urine specific gravity (USG) was measured to determine initial hydration status. Subjects were weighted nude before and after the exercise session. During exercise, all subjects had free access to sports drinks bottles, which were weighed before and after training. Urine output was also monitored. RESULTS: 112 subjects (51.9%) appeared to be inadequately hydrated before exercise because they showed USG ≥1.020; 20 of them (9.3%) with a USG ≥1.030. The sweat volume lost was 880+356 mL (200-2162 mL) and 518+177 mL (88-1010 mL) for men and women respectively; fluid intake was 733+293 mL (38-1356 mL) in men and 600+299 mL (0-1740 mL) in women. On average, men replaced 98+74% and women 129+81% of their sweat losses, but this ranged from none to 600%. 144 subjects (66.4%) maintained their body mass (BM) (range from -0.5 to 0.5%), while 34 subjects (15.7%) gained more than 0.5% of their BM and 39 subjects (18%) had a BM loss >0.5% (only one subject finished exercise with a BM loss >2%). CONCLUSIONS: There was a large variation between individuals in the sweat rate and drinking behavior. A significant percentage of the subjects arrived already hypohydrated to the exercise bout, even though they have knowledge about hydration. Coaches and fitness trainers should develop a personalize hydration strategy to help athletes and match their sweat losses. Supported by Gatorade Sports Science Institute®

Sodium bicarbonate for the prevention of contrast-induced nephropathy: a meta-analysis of 17 randomized trials

Contrast-induced nephropathy (CIN) is a common cause of acute kidney injury. Several preventive therapies for this injury have been tested; however, there is still no consensus on the optimal protocol. We performed a systematic search of the National Library of Medicine and the Cochrane Library databases from January 1985 to November 2008 to identify randomized controlled studies examining sodium bicarbonate as a preventive measure for CIN in humans. We also reviewed conference abstracts from cardiology nephrology and radiology meetings from 2004 to 2008. A change in serum creatinine levels defined by an absolute (>or=0.5 mg/dl) or percentage (>or=25%) increase in the serum creatinine level is defined as CIN. The primary outcome measure was the incidence of CIN, and the secondary outcome measures were: change in serum creatinine from baseline, requirement for renal replacement therapy and death. Seventeen randomized controlled trials have investigated the role of sodium bicarbonate for prophylaxis of CIN. The overall incidence of CIN was 11.3%. Using the results from all 17 studies that compared bicarbonate versus saline, the pooled relative risk of developing CIN was 0.54 (95% CI, 0.36-0.83) in the intervention arm, indicating a significant benefit from sodium bicarbonate. The pooled relative risk of CIN was 0.57 (95% CI, 0.35-0.95) when we analyzed for the studies that compared the effects sodium bicarbonate to NAC on development of CIN. There was no difference in the rates of requirement for renal replacement therapy and death. The use of sodium bicarbonate appears to reduce the incidence of CIN when compared to other preventive strategies for CIN without a significant difference in the requirement of renal replacement therapy and mortality. There are study heterogeneity and publication biases. Further adequately powered randomized controlled studies are needed to determine whether sodium bicarbonate will reduce the clinically meaningful outcomes (e.g., need for dialysis or death) and optimal hydration strategy in high-risk patients.

Fluid Replacement Knowledge and Sources of Hydration Information among Illinois High School Athletic Coaches: A Pilot Study

Objective: The purpose of this study was to examine Illinois high school coaches’ knowledge of hydration and fluid replacement strategies. We also sought to identify their primary sources of fluid replacement information. Design: Descriptive Survey. Participants: 22 Coaches who were members of the Illinois High School Association were the survey respondents in this study. The mean age (±SD) of subjects was 37.4(±11.5) years with an average coaching experience of 11.4(±8.96) years. Intervention: A questionnaire was developed based upon the National Athletic Training Association’s Position Stand and the American College of Sports Medicine’s roundtable discussion of fluid replacement and hydration. The instrument contained three sections: 1) demographic information, 2) sources of hydration information, and 3) knowledge assessment of fluid replacement guidelines. The instrument was examined for face and content validity by three exercise physiology experts, one of whom had substantial expertise in sport nutrition. Main Outcomes Measures: Descriptive statistics were used to identify the sources of information and scores on the knowledge assessment. Consistent with similar studies, a score of 80% was used for the passing rate for the knowledge assessment. A chi square test with a significance set a priori at p &lt;.05 was used to determine whether a difference existed between those with formal fluid replacement and exercise physiology training and those without in regards to passing the knowledge assessment. Results: 22 surveys were returned from 500 coaches that were randomly selected for mailing, resulting in a response rate of 4.4%. The mean assessment score was 12.7 (± 1.77) correct responses out of a possible 17. Only 12 participants (54.5%) obtained a passing score on the questionnaire, indicating nearly half of the spending coaches had an unacceptable level of hydration/fluid replacement knowledge. The chi square test revealed no significant difference in passing rates between those coaches with fluid replacement training (p= .394) or formal exercise physiology background (p= .088). The primary sources of information for the majority (&gt;50%) of coaches was from magazines, conferences, and medical staff. Conclusions: The results from the hydration and fluid replacement questionnaire indicate that a large percentage of Illinois high school coaches do not posses adequate knowledge related to fluid replacement for their athletes. The nature of the survey may have contributed to the response rate. The low response rate for this survey should be taken into consideration and, thus, the results interpreted with caution. Practical Applications: Professional associations should consider targeting coaching magazines and conferences to share critical information related to fluid replacement. Coaches must also take responsibility and keep abreast of the latest information related to the safety of their athletes.

Level of knowledge and hydration strategies of young soccer players

The aim of this study was to investigate fluid replacement strategies of young soccer players and their level of knowledge regarding hydration management. A total of 216 males (age: 18 ± 0.9 years) playing soccer for 8.7 ± 2.6 years were studied. The participants were members of four elite and subelite Brazilian soccer clubs. An exploratory descriptive study was conducted using a self-administered questionnaire consisting of 18 objective questions. The main results indicated that 32.3% and 30.1% of the athletes do not have an appropriate strategy for fluid replacement during competitions and training, respectively. In addition, 1.4% and 4.6% of the subjects reported to ingest no fluids during these exercise conditions. When asked about the type of solution (water or isotonic solution) consumed before, during and after exercise, water was the main fluid ingested during these periods. Approximately 80 athletes only ingest fluids when feeling thirsty. Coca-Cola® accounted for 11.1% of ingested fluids. Only 27.8% of the participants measure their body weight and 54.2% were unaware of the adequate strategy for fluid replacement. The most common symptoms reported by the athletes were cramps (53.2%), intense thirst (37.5%), and headache (33.8%). These results suggest that young soccer players have inappropriate fluid replacement habits, a fact that may lead to low performance during training or competition.

Pregame Urine Specific Gravity and Fluid Intake by National Basketball Association Players During Competition

Urine specific gravity (USG) has been used to estimate hydration status in athletes on the field, with increasing levels of hypohydration indicated by higher USG measurements (eg, greater than 1.020). Whether initial hydration status based on a urine measure is related to subsequent drinking response during exercise or athletic competition is unclear. To determine the relationship between pregame USG and the volume of fluid consumed by players in a professional basketball game. Cross-sectional study. Basketball players were monitored during Summer League competition. Players (n = 29) from 5 teams of the National Basketball Association agreed to participate. Pregame USG was measured for each player on 2 occasions. Athletes were given ad libitum access to fluid during each game and were unaware of the purpose of the study. Volume of fluid intake was measured for each player. To assess sweat loss, athletes were weighed in shorts before and after each game. Sweat loss ranged from 1.0 to 4.6 L, with a mean sweat loss of 2.2 +/- 0.8 L. Fluid intake ranged from 0.1 to 2.9 L, with a mean fluid intake of 1.0 +/- 0.6 L. Pregame USG was greater than 1.020 in 52% of the urine samples collected and was not correlated with fluid volume consumed during either of the games (r = 0.15, P = .48, and r = 0.15, P = .52, respectively). Approximately half of the players began the games in a hypohydrated state, as indicated by USG. Fluid intake during the game did not compensate for poor hydration status before competition. Furthermore, sweat losses in these players during games were substantial (greater than 2 L in approximately 20 minutes of playing time). Therefore, both pregame and during-game hydration strategies, such as beverage availability and player education, should be emphasized.

A Review of Fluid and Hydration in Competitive Tennis

Hypohydration is known to impair performance and increases the risk of heat injury. Therefore, the consumption of appropriate fluid volumes before, during, and after tennis play is important to maintain physiological homeostasis and performance. Tennis is a sport that typically has points lasting fewer than ten seconds, with short-to-moderate rest periods between each work bout. This sequence is repeated over hours. Most fluid and hydration research has focused on continuous aerobic exercise, which provides vastly different physiological strain compared with tennis practice and competition. Consequently, practical recommendations on maintaining hydration status for aerobic continuous exercise may not be appropriate for tennis athletes. Tennis players can sweat more than 2.5 L.h(-1) and replace fluids at a slower rate during competition than in practice. In warm and hot environments, electrolyte-enhanced fluid should be consumed at greater than >200 mL per changeover and ideally closer to 400 mL per changeover. Tennis scientists, coaches, and players need to individualize hydration protocols to arrive at the optimal hydration strategy.

Development of Individual Hydration Strategies for Athletes

Athletes are encouraged to begin exercise well hydrated and to consume sufficient amounts of appropriate fluids during exercise to limit water and salt deficits. Available evidence suggests that many athletes begin exercise already dehydrated to some degree, and although most fail to drink enough to match sweat losses, some drink too much and a few develop hyponatremia. Some simple advice can help athletes assess their hydration status and develop a personalized hydration strategy that takes account of exercise, environment, and individual needs. Preexercise hydration status can be assessed from urine frequency and volume, with additional information from urine color, specific gravity, or osmolality. Change in hydration during exercise can be estimated from the change in body mass that occurs during a bout of exercise. Sweat rate can be estimated if fluid intake and urinary losses are also measured. Sweat salt losses can be determined by collection and analysis of sweat samples, but athletes losing large amounts of salt are likely to be aware of the taste of salt in sweat and the development of salt crusts on skin and clothing where sweat has evaporated. An appropriate drinking strategy will take account of preexercise hydration status and of fluid, electrolyte, and substrate needs before, during, and after a period of exercise. Strategies will vary greatly between individuals and will also be influenced by environmental conditions, competition regulations, and other factors.

Hydration Status, Knowledge, and Behavior in Youths at Summer Sports Camps

To assess the hydration status and level of hydration knowledge of youths at summer sports camps. Sixty-seven active youths, 57 males (mean +/- SD, 12 +/- 2 y, 136 +/- 16 cm, 50.6 +/- 21.1 kg) and 10 females (13 +/- 2 y, 153 +/- 8 cm, 45.2 +/- 9.0 kg) participated in 4 d of sports camp. Hydration status was assessed before the first practice (AM) and after the second practice (PM). Participants completed surveys assessing hydration knowledge (HAQ) and hydration habits on day 3 and a self-assessment (EQ#1). Mean AM urine specific gravity (USG) and urine osmolality (Uosm) scores ranged from minimal to significant dehydration across 4 d, even when temperatures were mild. Correlations between hydration indices and EQ#1, ranging from 0.11 to -0.51, were statistically significant (P < .05), indicating that subjects recognized when they were doing a good or bad job hydrating. HAQ did not correlate strongly with hydration indices suggesting other impediments to hydration. Thirst correlated negatively with EQ#1 (from -0.29 to -0.60). Hydration at summer sports camp is a concern and special efforts need to be made to help youths develop hydration strategies.

Formal Total Synthesis of RK-397 via an Asymmetric Hydration and Iterative Allylation Strategy

A formal total synthesis of the oxopentaene macrolide antibiotic RK-397 has been achieved. Nine stereocenters were established by a combination of allylation and our asymmetric hydration reactions and a 1,5 anti-selective aldol reaction. The synthesis proceeded in 19 steps from simple achiral conjugated dienoates.

The Relationship of Hydration Strategies and NSAIDs Use on Self-Reported Symptoms of Dehydration and Hyponatremia in Runners Participating in the ING Georgia Marathon

Participants of the 2007 ING Georgia Marathon completed an on-line survey that inquired about common hydration strategies and frequency of NSAIDs use. PURPOSE: To investigate the degree to which runners follow established hydration protocols, and whether NSAIDs use increased the severity and/or frequency of symptoms associated with dehydration and hyponatremia. METHODS: The survey procedure was approved by the IRB of Georgia State University. The electronic sign-up for the marathon included an option to complete this survey, which contained questions on demographics (age, gender, height, weight, ethnicity, education, income), where runners live and train (using zip codes), NSAIDs use (type, frequency of use, amount of use), hydration strategy (type and amounts of beverages consumed, frequency and timing of consumption), and frequency of signs and symptoms associated with dehydration and/or hyponatremia (nausea, dizziness, headache, edema, breathlessness, vomiting, memory impairment, balance loss, exercise associated weight change). RESULTS: 2,073 volunteer participants (15% of race registrants) completed the survey [(1136 females (F); 937 males(M)]. Mean age was 39 yr ± 10.5 (F 37.5 yr ± 10.0; M 40.9 yr ± 10.8). Approximately 40% (n=837) of the subjects reported taking NSAIDs before or after training (F 42.7%; M37.6%), and approximately 26% (n=533) planned to take NSAIDs before the ING marathon (F 28.3%; M 22.6%). More subjects reported having a competition-related drink strategy [(total 66% n=1368); (F 62.9% n=714); (M 69.8% n=654)] than for long training runs [(total 57.6% n=1195); (F 55.8% n=634); (M 59.9% n=561)]. There were fewer symptoms of dehydration/hyponatremia in those who consumed beverages during runs than those who did not (p < .05). NSAIDs consuming F, but not M, reported less breathlessness than F not taking NSAIDs (p=.014). NSAIDs consuming M and F reported fewer headaches than those not taking NSAIDs (p<.04). There was also greater frequency of swelling, nausea, and memory impairment among NSAIDs users (p<.03). CONCLUSIONS: These findings suggest that nearly 35% of marathon participants do not have an appropriate hydration strategy, which increases heat stress disorder risk. There was some indication that NSAIDs use exacerbates the symptoms of dehydration and/or hyponatremia.

Core temperature and hydration status during an Ironman triathlon

Background: Numerous laboratory based studies have documented that aggressive hydration strategies (∼1–2 litres/h) are required to minimise a rise in core temperature and minimise the deleterious effects of hyperthermia on...