The purpose of this study was to identify and to compare the effects of ingesting liquids during a 16-km military march under moderate environmental conditions. Twenty-six volunteer male subjects were randomly divided into two groups. Group GW received water (n=12), and group GP received an electrolytic carbohydrate solution (n=14). Blood and urine samples were obtained immediately before and after the march. No significant differences between the drinks were found for any of the measured variables. However, important results (p < 0.05) were observed by comparing variables before and after exercise. The variables included sodium, hematocrit, red blood cell, hemoglobin, and lactic acid levels and body weight (group GW) and sodium, potassium, hematocrit, red blood cell, hemoglobin, and lactic acid levels (group GP). Under the environmental conditions and hydration procedures applied, the results of this study showed similarities in the behavior of the variables, regardless of the kind of beverage consumed. PMID: 17274272 [PubMed - indexed for MEDLINE]