Accession Number : ADA137194

Title :   Exercise in the Heat. Effects of Saline or Bicarbonate Infusion,

Corporate Author : ARMY RESEARCH INST OF ENVIRONMENTAL MEDICINE NATICK MA

Personal Author(s) : Francesconi,R P ; Hubbard,R W

PDF Url : ADA137194

Report Date : 01 Dec 1983

Pagination or Media Count : 30

Abstract : Adult, male rats (N=17/group, 300-320 g, physically untrained) were exercised (9.14 m/min) in the heat (35 C) to hyperthermic exhaustion (Tre = 43 C) after infusion of 2 ml of 7.5% sodium bicarbonate (BIC) or 2 ml of 0.9% sodium chloride (SAL). BIC or SAL administration had no effects on endurance when compared with rats receiving no exogenous fluid (CON) while the rate of heat gain was significantly increased in the BIC-treated group. Following exercise, the BIC group manifested significantly decreased hematocrit and plasma protein levels, but exaggerated increments in plasma osmolality. Lactate levels were significantly increased in all three groups with no notable inter-group differences. While venous (v) blood pH and bicarbonate levels were decreased following exercise in the SAL and CON groups, they were unchanged in the BIC group. While vPCO2 was unaffected by fluid administration in all three groups, vPO2 was significantly increased following exercise in the heat in all groups. We concluded from these experiments that while BIC infusion prevented the acidosis and hypobicarbonatemia induced by exercise in the heat to hyperthermic exhaustion, no beneficial effects on physical performance or thermoregulation ensued.

Descriptors :   *Exercise(Physiology), *Heat stress(Physiology), Bicarbonates, Saline solution, Sodium chloride, Hematocrit, pH factor, Level(Quantity), Lactates, Hyperthermia, Rats

Subject Categories : Stress Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE