This study examined the effects of hypohydration on plasma volume and red cell volume during rest in a comfortable (20 degrees C, 40% relative humidity) and exercise in a hot-dry (49 degrees C, 20% relative humidity) environment. A group of six male and six female volunteers [matched for maximal O2 uptake (VO2 max)] completed two [...]

Experiments were undertaken to determine the effects of hydration status on a) orthostatic responses, and on b), relative changes in intravascular volume and protein content, during 70 degrees head-up tilt (HUT). Six men underwent 45 min of HUT, preceded by 45 min supine, first dehydrated, and again 105 min later after rehydration with water. Heart [...]

To determine the effect of hydration on the early osmotic and intravascular volume and endocrine responses to water immersion the hematocrit, hemoglobin, plasma renin activity (PRA), and plasma electrolyte, aldosterone (PA), and vasopressin (PVP) concentrations were measured during immersion following 24-h dehydration; these were compared with corresponding values following rapid rehydration. Six men and one [...]

If plasma vasopressin (PVP), plasma renin (PRA), and plasma aldosterone (PA) responses to change in posture are mediated only by alterations in intrathoracic baroreceptor activity, hydration status should have minimal influence on these responses. To test this hypothesis, six male subjects underwent 45 min of 70 degree head-up tilt (HUT) following 26 h dehydration, and [...]

Euhydrated and dehydrated subjects exercised in a hot and a cold environment with our aim to identify factors that relate to reductions in stroke volume (SV). We hypothesized that reductions in SV with heat stress are related to the interaction of several factors rather than the effect of elevated skin blood flow. Eight male endurance-trained [...]

Five young unacclimatised subjects were exposed for 4 h at 34 degrees C (10 degrees C dew-point temperature and 0.6 m X s-1 air velocity), while exercising on a bicycle ergometer: 25 min work--5 min rest cycles for 2 hours followed by 20 min work--10 min rest cycles for two further hours. 5 experimental sessions [...]

This investigation determined the effect of different rates of dehydration, induced by ingesting different volumes of fluid during prolonged exercise, on hyperthermia, heart rate (HR), and stroke volume (SV). On four different occasions, eight endurance-trained cyclists [age 23 +/- 3 (SD) yr, body wt 71.9 +/- 11.6 kg, maximal O2 consumption 4.72 +/- 0.33 l/min] [...]

There are many occupations where workers undergo daily exposure to rigorous environments, often with only limited access to fluids. Such conditions warrant the use of an electrolyte rehydration beverage; however, the long-term use of such beverages may pose potential health risks due to the increase in dietary sodium intake. This study proposed to determine blood [...]

Diarrhea in childhood is very frequent (two episodes/year/children less of 5 years), rarely fatale (mostly mild) and not requiring additional exploration. But it can justify a hospitalization in case of dehydration (delay of care) or risk of dehydration. It is mainly of viral origin (rotavirus +++) and it has for main complication dehydration. Diagnosis and evaluation [...]

Thirst is a common and troublesome symptom for patients with moderate to severe heart failure. The pharmacological and non-pharmacological treatment as well as the nature of the disease itself causes increased thirst. There is no evidence in the literature about the usefulness of fluid restriction for heart failure patients. Formerly, when very little pharmacological treatment was available, fluid restriction was one of the few interventional options [...]