Interrelationships between Physical Fitness Scores

Abstract

Ten moderately well-conditioned male students at the University of Toledo ran on a treadmill, fully attired in football equipment, with an environmental temperature of 90 F and relative humidity of 70%. Each subject was partially acclimatized and then exposed to the experimental conditions on five consecutive days (balanced Latin square). Four 1-liter water replacement schedules (designed to test specific hypotheses), and a control of no water, served as five levels of the independent variable. Data were collected on rectal temperature, heart rate, pulse pressure, specific gravity changes for whole blood and for plasma, and sweat loss. Results showed that water ingestion early during the work session combated the effects of heat stress better than late administration; however, this advantage was reduced toward the end of the work session. The results were mixed concerning the relative merits of ingesting the water in one or two administrations.