To determine how osmolality of an orally ingested fluid-replacement beverage would alter intestinal fluid absorption from the duodenum and/or jejunum during 85 min of cycle exercise (63.3 +/- 0.9% peak O2 uptake) in a cool environment (22 degreesC), seven subjects (5 men, 2 women, peak O2 uptake = 54.5 +/- 3.8 ml . kg-1 . [...]
This Position Stand provides guidance on fluid replacement to sustain appropriate hydration of individuals performing physical activity. The goal of prehydrating is to start the activity euhydrated and with normal plasma electrolyte levels. Prehydrating with beverages, in addition to normal meals and fluid intake, should be initiated when needed at least several hours before the [...]
PURPOSE:: Dehydration is hypothesized to cause exercise-associated muscle cramps (EAMC). The theory states that dehydration contracts the interstitial space thereby increasing the pressure on nerve terminals and cramps ensue. Research supporting this theory is often observational and fatigue is rarely controlled. Inducing cramps with electrical stimulation minimizes many of the confounding factors associated with exercise-induced [...]
CONTEXT: The protective equipment worn during American football has been shown to increase thermal strain; however, the perception of this increased heat has not been examined. OBJECTIVE: To evaluate perceptual responses of American football players while wearing different uniforms during exercise in the heat and to evaluate how these responses may be used to monitor [...]
CONTEXT: In hot environments, the American football uniform predisposes athletes to exertional heat exhaustion or exercise-induced hyperthermia at the threshold for heat stroke (rectal temperature [T(re)] > 39 degrees C). OBJECTIVE: To evaluate the differential effects of 2 American football uniform configurations on exercise, thermal, cardiovascular, hematologic, and perceptual responses in a hot, humid environment. [...]
The objective of this study was to evaluate the utility of ultrasound velocity (UV) to detect changes in the hydration status of wrestlers after undergoing acute dehydration and a 2-hour rehydration period. Forty-seven NCAA wrestlers (mean+/-SEM); age 19.1+/-0.2 years, height 1.73+/-0.1 m, body mass (BM) 79.4+/-2.4 kg were tested in euhydrated, dehydrated, and a 2-hours [...]
Two studies were conducted to investigate gastrointestinal (GI) tolerance of high carbohydrate (CHO) intakes during intense running. The first study investigated tolerance of a CHO gel delivering glucose plus fructose (GLU+FRC) at different rates. The second study investigated tolerance of high intakes of glucose (GLU) vs. GLU+FRC gel. Both studies used a randomized, 2-treatment, 2-period [...]
PURPOSE: To investigate the effect of ice slurry ingestion on thermoregulatory responses and sub-maximal running time in the heat. METHODS:: On two separate occasions, in a counterbalanced order, ten males ingested 7.5 g.kg of either ice slurry (-1 degrees C) or cold water (4 degrees C) before running to exhaustion at their first ventilatory threshold [...]
The purpose of this study was to determine the influence of hydration status on pacing of trail runners in the heat (wet bulb globe temperature = 26.2 +/- 1.8 degrees C). A randomized, crossover design was used and the participation occurred within a 2-week period. Seventeen competitive, well-trained distance runners (9 men, 8 women, age [...]
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 [...]