Accession Number : ADA188008

Title :   Gastric Emptying During Exercise: Effects of Acute Heat Stress, Acclimation and Hypohydration,

Corporate Author : ARMY RESEARCH INST OF ENVIRONMENTAL MEDICINE NATICK MA

Personal Author(s) : Neufer, P D ; Young, Andrew J ; Sawka, Michael N

PDF Url : ADA188008

Report Date : Oct 1987

Pagination or Media Count : 31

Abstract : To determine the effects of acute heat stress, heat acclimation and hypohydration on the gastric emptying rate of water (W) during treadmill exercise, ten physically fit men ingested 400 ml of W prior to each of three 15-min bouts of exercise (treadmill, about 50% VO2 max) on five separate occasions. Stomach contents were aspirated after each exercise bout. Before heat acclimation (ACC), experiments were performed in a neutral (18 C), hot (49 C) and warm (35 C) environment. Subjects were euhydrated for all experiments before ACC. After ACC, the subjects completed two more experiments in the warm (35 C) environment; one while euhydrated and a final while hypohydrated (5% of body weight). The volume of ingested water emptied into the intestines were inversely correlated (P0.01) with the rectal temperature (r=0.76) and heart rate (r=0.88) at the completion of each exercise bout. The following new observations were made: 1) exercise in a hot (49 C) environment impairs gastric emptying rate as compared to a neutral (18 C) environment; 2) exercise in a warm (35 C) environment does not consistently affect gastric emptying before or after heat acclimation; but 3) exercise in a warm environment when hypohydrated reduces gastric emptying rate. Reductions in gastric emptying appeared to be related to the severity of the thermal and cardiovascular strain induced by exercise/heat stress.

Descriptors :   *ACCLIMATIZATION, *EXERCISE(PHYSIOLOGY), *HEAT STRESS(PHYSIOLOGY), *STOMACH, *BIOLOGICAL ABSORPTION, BODY TEMPERATURE, CARDIOVASCULAR SYSTEM, HEART RATE, HEAT, INTESTINES, RATES, RECTUM, STRESS(PHYSIOLOGY), TREADMILLS, WATER, DEHYDRATION

Subject Categories : Stress Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE