A ten-stage treadmill test was developed and standardized to secure the VO2max of male and female rats assigned to various cross-sectional and longitudinal experimental groups. Repeated measurements indicated that the test procedure was reliable and could be used for research purposes. When the test was used with different strains, the untrained Sprague-Dawley rats had significantly higher VO2max values than animals of the Wistar-Kyoto (WKY) or the Okamoto-Aoki (SHR) strains. Exercise schedules were evaluated that were similar to those previously used by various investigators and it was found that most were exercising their rats at levels exceeding 75% VO2max. After 6--10 wk of chronic exercise, significant increases in VO2max occurred that ranged between 12 and 26%. Longitudinal studies (1 yr) with hypertensive (SHR) rats revealed that it was more desirable to logarithmically evaluate the relationship between VO2max and body mass than by the conventional method of ml . kg-1 . min-1. When this approach was used with SHR animals, the VO2max differences between the sexes were not apparent until the animals were 1 yr of age. On the other hand, training by male SHR rats caused significant increases in VO2max regardless of the method used to express the results. It is recommended that future studies designed to elucidate exercise mechanisms in rats should include a standardized VO2max test.

Posm accurately identifies a state of euhydration and is sensitive to changes in hydration status during acute dehydration and rehydration. Usg and Uosm are also sensitive to changes in hydration status but lag behind during periods of rapid body fluid turnover and therefore correlate only moderately with Posm during acute dehydration.

Dehydration not only reduces athletic performance, but also places athletes at risk of health problems and even death. For athletes, monitoring hydration has significant value in maximising performance during training and competition. It also offers medical personnel the opportunity to reduce health risks in situations where athletes engage in intentional weight loss. Simple non-invasive techniques, including weight monitoring and urine tests, can provide useful information. Bioimpedance methods tend to be easy to use and fairly inexpensive, but generally lack the precision and accuracy necessary for hydration monitoring. Blood tests appear to be the most accurate monitoring method, but are impractical because of cost and invasiveness. Although future research is needed to determine which hydration tests are the most accurate, we encourage sports teams to develop and implement hydration monitoring protocols based on the currently available methods. Medical personnel can use this information to maximise their team's athletic performance and minimise heat- and dehydration-related health risks to athletes.

To reduce the adverse consequences of exertion-related and acute intentional dehydration research has focused on monitoring hydration status. This investigation: 1) compared sensitivity of urine specific gravity (Usg), urine osmolality (U(osm)) and a criterion measurement of hydration, plasma osmolality (P(osm)), at progressive stages of acute hypertonic dehydration and 2) using a medical decision model, determined whether Usg or U(osm) accurately reflected hydration status compared to P(osm) among 51 subjects tested throughout the day. Incremental changes in P(osm) were observed as subjects dehydrated by 5% of body weight and rehydrated while Usg and U(osm) showed delayed dehydration-related changes. Using the medical decision model, sensitivity and specificity were not significant at selected cut-offs for Usg and U(osm). At the most accurate cut-off values, 1.015 and 1.020 for Usg and 700 m(osm)/kg and 800 m(osm)/kg for U(osm), only 65% of the athletes were correctly classified using Usg and 63% using U(osm). P(osm), Usg, and U(osm) appear sensitive to incremental changes in acute hypertonic dehydration, however, the misclassified outcomes for Usg and U(osm) raise concerns. Research focused on elucidating the factors affecting accurate assessment of hydration status appears warranted.

The WM practices of college wrestlers appeared to have improved compared to wrestlers sampled previously. Forty percent of the wrestlers were influenced by the new NCAA rules and curbed their weight loss practices. Education is still needed, as some wrestlers are still engaging in dangerous WM methods.

No abstract

Distilled water, a carbohydrate-electrolyte (CE; 4% sucrose, 2% glucose, 17.2 meq/l NaCl, and 2.8 meq/l KCl) solution, or a 10% glucose solution, all containing the nonabsorbed indicator polyethylene glycol (PEG) and deuterium oxide (D2O, 30 ppm), were infused (15 ml/min) into the duodenojejunum of seven men by using the triple lumen technique. Net water absorption was determined directly from the change in PEG concentration and was calculated from plasma D2O derived from D2O in the perfusion solutions. The protocol included a 45-min equilibration period followed by a 90-min test period. Intestinal samples were drawn at 10-min intervals from 15 to 45 min and at 15-min intervals thereafter. Blood was drawn at 45, 50, 55, 60, 75, 90, 105, 120, and 135 min. Intestinal samples were analyzed for D2O, Na+, K+, osmolality, PEG, and glucose; blood was analyzed for D2O. Results (+/- SE; positive values secretion, negative values absorption) showed net fluid absorption from distilled water (-9.40 +/- 1.28 ml.h-1.cm-1) and the CE (-13.30 +/- 1.22 ml.h-1.cm-1) solution, but net secretion (4.40 +/- 1.25 ml.h-1.cm-1) from the 10% glucose solution. All values were significantly (P less than 0.05) different from each other. Perfusing the CE solution caused net Na+ and K+ absorption, whereas perfusing the 10% dextrose solution caused net electrolyte secretion. Rates of D2O accumulation in the plasma were independent of the solutions perfused.(ABSTRACT TRUNCATED AT 250 WORDS)

The order in which clinical information was presented influenced physicians' estimates of the probability of disease. The clinical history and physical examination were given more weight by physicians who received this information last.