David N. Camaione

Effects of oral and intravenous rehydration on ratings of perceived exertion and thirst

The purpose of this investigation was to compare the effects of oral and intravenous saline rehydration on differentiated ratings of perceived exertion (RPE) and thirst. Eight men underwent three randomly assigned rehydration treatments following a 2- to 4-h exercise-induced dehydration bout to reduce body weight by 4%. Treatments included 0.45% saline infusion (i.v.), 0.45% saline oral ingestion (ORAL), and no fluid (NF). Following rehydration and rest (2 h total), subjects walked at 50% VO2max for 90 min at 36 degrees C (EX). Central RPE during ORAL was lower (P < 0.05) than i.v. and NF throughout EX. Local RPE during NF was higher (P < 0.05) than i.v. and ORAL at minutes 20 and 40 of EX and overall RPE during NF was higher (P < 0.05) than ORAL at minutes 20 and 40 of EX. Significant correlations were found between overall RPE and mean skin temperature for i.v. (r = 0.72) and NF (r = 0.75), and between overall RPE and thirst ratings for i.v. (r = 0.70). Thirst ratings were not different among trials at postdehydration. Following rehydration, thirst was higher (P < 0.05) during NF than i.v. and ORAL and lower (P < 0.05) during ORAL than i.v. at all subsequent time points. Results suggest that oral rehydration is likely to elicit lower RPE and thirst ratings compared with intravenous rehydration.

Predictors of referral to cardiac rehabilitation and cardiac exercise self-efficacy

Cardiac rehabilitation (CR) has known benefits after myocardial infarction (MI) or coronary artery bypass surgery (CABG). Yet, only a small percentage of patients are referred for outpatient CR after hospital discharge. This study investigates patient characteristics related to referral to CR and cardiac exercise self-efficacy, a salient predictor of health behavior change and maintenance. Two hundred nineteen patients enrolled in the study. Of the 185 patients who were CR candidates, 74 were referred to CR. Logistic regression analysis was used to identify variables related to CR referral. Results indicate that patient characteristics of having had fewer MIs or CABGs, having attended CR in the past, and being less physically active during leisure time are related to an increased likelihood of being referred to CR. Multiple regression analysis indicates that leisure physical activity is a predictor of cardiac exercise self-efficacy. Implications for nurses who recruit patients for CR are discussed.

a Comparison of Conventional Versus Anaerobic Threshold Exercise Prescription Methods in Subjects With Left Ventricular Dysfunction

This study compared conventional exercise prescription methods with an anaerobic threshold (AT) method in a population with left ventricular dysfunction (LVD) to determine: 1) if a significant number of conventionally prescribed training heart rate ranges (THR) were above anaerobic threshold; and 2) if there was a significant decrease in ventricular function at the prescribed heart rate ranges as assessed by Doppler ultrasound variables, ascending aortic blood velocity (AABV) and peak acceleration (PA). The sample consisted of twelve male subjects with documented LVD (ejection fraction

The effect of differential training on isokinetic muscular endurance during acute thermally induced hypohydration

The purpose of this study was to test the effect of acute thermal hypohydration on the muscle endurance performance of three groups of differentially trained subjects. Group I consisted of six anaerobically trained athletes, Group II consisted of five aerobically trained athletes, and Group III consisted of six sedentary indi viduals. Experimental trials involved maximal leg exten sions performed on a Cybex II dynamometer under conditions of euhydration and hypohydration of minus 3% body weight. Integrated electromyographic data were also collected during each trial to factor out mo tivation as a variable. The maximum number of leg extension repetitions performed at or above 50% of each subjects peak torque output were compared between treatments and among the three groups. A 2 x 3 factorial analysis of variance (ANOVA) showed a significant decrease in muscle endurance when com paring euhydration to hypohydration among the anaer obically trained subjects as well as among the seden tary subjects (P < 0.05). The aerobically trained sub jects showed no significant decline in muscle endurance when comparing performance under both experimental conditions. It was hypothesized that the training adap tations that occur with aerobic conditioning and are primarily associated with increased plasma volume may be the key to explaining these results.

Effects of Continuous Passive Motion, Walking, and a Placebo Intervention on Physical and Psychological Weil-being

To investigate claims that continuous passive motion tables improve physiological and psychological well-being, 94 healthy women were assigned randomly to 12-week programs involving a placebo-control meeting, unsupervised walking, continuous passive motion, and continuous passive motion plus diet. Program outcomes were assessed by analysis of pre- and post-treatment fasting blood chemistry, a graded, symptom-limited maximal exercise test, anthropometric measurements of skinfold and circumferences, and flexibility, as well as anxiety, depression, mood, and somatic distress. Significant improvements were found in cholesterol, weight, suprailiac and weighted skinfold, arm circumference, hip flexibility, and exercise endurance in the active groups. Women in the continuous passive motion plus diet condition had a significant weight loss and improved lipid profile. Committed walkers significantly outperformed women in the continuous passive motion groups on cardiovascular fitness but were more likely to terminate participation in the program prematurely. Results suggested that involvement in continuous passive motion generates positive expectancies for improved physical and psychological well-being, which may improve adherence to health-promoting regimens.