The aim of this study was to examine whether ingesting water alone, or dextrose (7.5 g x 100 ml(-1)) with electrolytes, or fructose/corn solids (7.5 g x 100 ml(-1)) (400 ml every 20 min) would reduce the perceived exertion associated with 16 km (3 h) walking/running in the heat compared with that perceived during exercise [...]
After a control experiment under initial normal hydration (N), five healthy unacclimated subjects were studied to investigate the effects of initial hypo- and hyperhydration on cardiovascular and thermo-regulatory responses to prolonged intermittent exercise in the heat (To = 36 degrees C; Tdp = 10 degrees C; Va = 0.6 m.s-1). Prior hydrohydration (O) was obtained [...]
This report describes a series of hyponatremia hospitalizations associated with heat-related injuries and apparent over-hydration. Data from the U.S. Army Inpatient Data System were used to identify all hospitalizations for hyposmolality/hyponatremia from 1996 and 1997. Admissions were considered as probable cases of overhydration hyponatremia if this was the only, or primary, diagnosis or if it [...]
Dehydration is known to decrease orthostatic tolerance and cause tachycardia, but little is known about the cardiovascular control mechanisms involved. To test the hypothesis that arterial baroreflex sensitivity increases during exercise-induced dehydration, we assessed arterial baroreflex responsiveness in 13 healthy subjects (protocol 1) at baseline (PRE-EX) and 1 h after (EX-DEH) 90 min of exercise [...]
No abstract available.
The purpose of the present study was to investigate the influence of hypohydration and fluid replacement on tolerance to an uncompensable heat stress. Eight healthy young males completed a matrix of six trials in an environmental chamber, set at 40 degrees C and 30% relative humidity, while wearing nuclear, biological, and chemical protective clothing. Subjects [...]
When performing physical work, sweat output often exceeds water intake, producing a body water deficit or dehydration. Specific to the work place, dehydration can adversely affect worker productivity, safety, and morale. Legislative bodies in North America such as the Occupational Safety and Health Administration (OSHA) and the American Conference of Governmental Industrial Hygienists (ACGIH) recommend [...]
No abstract available.
Expansion of blood volume (hypervolemia) has been well documented in both cross-sectional and longitudinal studies as a consequence of endurance exercise training. Plasma volume expansion can account for nearly all of the exercise-induced hypervolemia up to 2-4 wk; after this time expansion may be distributed equally between plasma and red cell volumes. The exercise stimulus [...]