Objective: : To present evidence-based recommendations that promote optimized fluid-maintenance practices for physically active individuals.Background: : Both a lack of adequate fluid replacement (hypohydration) and excessive intake (hyperhydration) can compromise athletic performance and increase health risks. Athletes need access to water to prevent hypohydration during physical activity but must be aware of the risks of overdrinking and hyponatremia. Drinking behavior can be modified by education, accessibility, experience, and palatability. This statement updates practical recommendations regarding fluid-replacement strategies for physically active individuals.Recommendations: : Educate physically active people regarding the benefits of fluid replacement to promote performance and safety and the potential risks of both hypohydration and hyperhydration on health and physical performance. Quantify sweat rates for physically active individuals during exercise in various environments. Work with individuals to develop fluid-replacement practices that promote sufficient but not excessive hydration before, during, and after physical activity.

Personalized hydration strategies play a key role in optimizing the performance and safety of athletes during sporting activities. Clinicians should be aware of the many physiological, behavioral, logistical and psychological issues that determine both the athlete’s fluid needs during sport and his/her opportunity to address them; these are often specific to the environment, the event and the individual athlete. In this paper we address the major considerations for assessing hydration status in athletes and practical solutions to overcome obstacles of a given sport. Based on these solutions, practitioners can better advise athletes to develop practices that optimize hydration for their sports.

Context: Recommended treatment for exertional heat stroke includes whole-body cold-water immersion (CWI). However, remote locations or monetary or spatial restrictions can challenge the feasibility of CWI. Thus, the development of a modified, portable CWI method would allow for optimal treatment of exertional heat stroke in the presence of these challenges. Objective: To determine the cooling rate of modified CWI (tarp-assisted cooling with oscillation [TACO]) after exertional hyperthermia. Design: Randomized, crossover controlled trial. Setting: Environmental chamber (temperature = 33.4°C ± 0.8°C, relative humidity = 55.7% ± 1.9%). Patients or Other Participants: Sixteen volunteers (9 men, 7 women; age = 26 ± 4.7 years, height = 1.76 ± 0.09 m, mass = 72.5 ± 9.0 kg, body fat = 20.7% ± 7.1%) with no history of compromised thermoregulation. Intervention(s): Participants completed volitional exercise (cycling or treadmill) until they demonstrated a rectal temperature (T_re) ≥39.0°C. After exercise, participants transitioned to a semirecumbent position on a tarp until either T_re reached 38.1°C or 15 minutes had elapsed during the control (no immersion [CON]) or TACO (immersion in 151 L of 2.1°C ± 0.8°C water) treatment. Main Outcome Measure(s): The T_re, heart rate, and blood pressure (reported as mean arterial pressure) were assessed precooling and postcooling. Statistical analyses included repeated-measures analysis of variance with appropriate post hoc t tests and Bonferroni correction. Results: Before cooling, the T_re was not different between conditions (CON: 39.27°C ± 0.26°C, TACO: 39.30°C ± 0.39°C; P = .62; effect size = −0.09; 95% confidence interval [CI] = −0.2, 0.1). At postcooling, the T_re was decreased in the TACO (38.10°C ± 0.16°C) compared with the CON condition (38.74°C ± 0.38°C; P < .001; effect size = 2.27; 95% CI = 0.4, 0.9). The rate of cooling was greater during the TACO (0.14 ± 0.06°C/min) than the CON treatment (0.04°C/min ± 0.02°C/min; t₁₅ = −8.84; P < .001; effect size = 2.21; 95% CI = −0.13, −0.08). These differences occurred despite an insignificant increase in fluid consumption during exercise preceding CON (0.26 ± 0.29 L) versus TACO (0.19 ± 0.26 L; t₁₂ = 1.73; P = .11; effect size = 0.48; 95% CI = −0.02, 0.14) treatment. Decreases in heart rate did not differ between the TACO and CON conditions (t₁₅ = −1.81; P = .09; effect size = 0.45; 95% CI = −22, 2). Mean arterial pressure was greater at postcooling with TACO (84.2 ± 6.6 mm Hg) than with CON (67.0 ± 9.0 mm Hg; P < .001; effect size = 2.25; 95% CI = 13, 21). Conclusions: The TACO treatment provided faster cooling than did the CON treatment. When location, monetary, or spatial restrictions are present, TACO represents an effective alternative to traditional CWI in the emergency treatment of patients with exertional hyperthermia.

McDermott BP, Casa DJ, O’Connor FG, Adams WB, Armstrong LE, Brennan AH, Lopez RM, Stearns RL, Troyanos C, Yeargin SW. Cold-water dousing with ice massage to treat exertional heat stroke: a case series. Aviat Space Environ Med 2009; 80:720–2. Introduction: We sought to determine the rate of cooling via a novel water ice therapy (WIT) as an alternative to cold-water immersion for the acute treatment of exertional heat stroke (EHS). Methods: Observations were made at the 2004-2008 Marine Corps Marathons (mean ± SD: 16.3 ± 4.9°C dry bulb, 32 ± 6% RH). Nine (seven men, two women) EHS patients (33 ± 6 yr of age; 268 ± 54 min average race time for six who finished) were observed during on-site treatment. Patients were treated while lying supine on a porous stretcher resting on a tub filled with cold water (~10-12°C). Medical personnel monitored T_re, doused the patient with water and massaged major muscle groups with ice bags until T_re decreased to 38.9°C. Patients were not immersed in water. Serial T_re and time were used to calculate cooling rates. Results: Final T_re (39.12 ± 0.63°C) was significantly lower than initial T_re (41.43 ± 0.71°C, P < 0.05). Cooling rates were 0.13 ± 0.04°C · min⁻¹. The decrease in T_re for the initial 6 min of WIT (0.38 ± 0.13°C) was significantly less than for the subsequent 6-min time period (1.31 ± 0.34°C, P < 0.001). Cooling rates for these time periods were significantly different (0.06 ± 0.02°C · min⁻¹ and 0.22 ± 0.06°C · min⁻¹, respectively, P < 0.05). Initial T_re was not correlated with overall cooling rate (r = 0.434, P = 0.244), or total cooling time required (17 ± 4 min; r = 0.207, P = 0.593). Survival rate was 100%. Conclusion: WIT provided cooling rates that were 70% as effective as those published for cold-water immersion with 8°C water (0.19°C · min⁻¹) and resulted in 100% patient survival.