Symptomatic hyponatremia during prolonged exercise in heat.

摘要: Although hyponatremia (HN) has been reported among endurance athletes, its etiology often remains uncertain and of great interest to clinicians physiologists. This case report presents physiologic evidence regarding the development HN during exercise in heat. A 21-yr-old male volunteer (K.G.) unexpectedly experienced symptomatic a research investigation that involved controlled sodium (Na+) intake (137 mEq Na+.d-1 for 7d) exercise-heat acclimation (41 degrees C; 30 min.h-1, 8 h.d-1 10 d). Fluid balance, variables, hematologic/hormone data were measured before after episode, with similar measurements recorded nine unaffected volunteers. The results indicated: 1) was verified K.G. (plasma Na+ < 130 mEq.l-1) only 4 h mild, intermittent heat; 2) K.G.'s heart rate, rectal temperature, blood pressure, losses sweat urine or = control subjects at all times; 3) between hours 4-7, an inappropriately large release vasopressin coincided decrease volume 0 ml.h-1. It concluded (10.3 l.7h-1) retention (2.77 water "low normal" initial plasma (134 primary factors K.G., whereas normal served exacerbate HN.