This investigation determined if 3 levels of controlled caffeine consumption affected fluid-electrolyte balance and renal function differently. Healthy males (mean +/- standard deviation; age, 21.6 +/- 3.3 y) consumed 3 mg caffeine . kg(-1) . d(-1). on days 1 to 6 (equilibration phase). On days 7 to 11 (treatment phase), subjects consumed either 0 mg [...]
Water in the human body is essential for metabolism, temperature regulation, and numerous other physiological processes that are consistent with good health. Accurate, precise, and reliable methods to assess body fluid compartments are needed. This review describes the hydration assessment techniques of isotope dilution, neutron activation analysis, bioelectrical impedance, body mass change, thirst, tracer appearance, [...]
Twelve 10- to 12-year-old healthy boys performed six 70-min intermittent exercise sessions (three 20-min cycling bouts at 50% VO2max with 5 min rest in between) over a 2-week period at 35 +/- 1 degrees C, 50 +/- 5% or 60 +/- 5% relative humidity. Subjects drank grape-flavored solution with 6% carbohydrate (2% glucose, 4% sucrose) [...]
Hypohydration (decreased total body water) exacerbates the catabolic hormonal response to endurance exercise with unclear effects on anabolic hormones. Limited research exists that evaluates the effect of hypohydration on endocrine responses to resistance exercise; this work merits attention as the acute postexercise hormonal environment potently modulates resistance training adaptations. The purpose of this study was [...]
Fetal renal pyelectasis is a frequent finding on routine obstetrical sonography. The cause of this pelvocalyceal dilatation is often not apparent, although urinary tract obstruction is the most important condition to be excluded. One of the many hypothetical explanations for minimal fetal renal pyelectasis suggests that aggressive maternal hydration before sonography leads to fetal diuresis [...]
Rapid and complete restoration of fluid balance after exercise is an important part of the recovery process, especially in hot, humid conditions, when sweat losses may be high. Rehydration after exercise can only be achieved if the electrolytes lost in sweat, as well as the lost water, are replaced. However, the amount of electrolytes lost [...]
Fluid replacement remains an important strategy for preserving exercise performance as dehydration in excess of 2% of body weight consistently impairs aerobic exercise performance. Too much of a good thing, however, can have negative health consequences as persistent drinking in excess of sweating rate can induce symptomatic exercise associated hyponatremia. This short review highlights new [...]
OBJECTIVE: This study tested the hypothesis that bioelectrical impedance vectors, group and individual, are valid indicators of total body water (TBW) and hydration status in women experiencing fluid gain and loss during and after pregnancy. METHODS: We measured TBW, assessed with D(2)O dilution, and resistance (R) and reactance (Xc), determined with 800 microA at 50 [...]
It is the position of the American College of Sports Medicine that adequate fluid replacement helps maintain hydration and, therefore, promotes the health, safety, and optimal physical performance of individuals participating in regular physical activity. This position statement is based on a comprehensive review and interpretation of scientific literature concerning the influence of fluid replacement [...]
The performance of both physical and mental tasks can be adversely affected by heat and by dehydration. There are well-recognized effects of heat and hydration status on the cardiovascular and thermoregulatory systems that can account for the decreased performance and increased sensation of effort that are experienced in the heat. Provision of fluids of appropriate [...]