Chronotropic incompetence (CI) has typically been assessed using maximal heart rate (MHR) achieved during a graded exercise test (GXT). Wilkoff et al recommended using a chronotropic/metabolic index (WI) consisting of the ratio between predicted maximal heart rate reserve (PMHRR) and metabolic reserve (MR) during submaximal exercise. Using a WI of <0.80 as evidence of CI, Lauer at al reported a prevalence of 14% for men and 12% for women within the Framingham cohort and indicated that the WI was independent of age, resting heart rate and exercise capacity (peak METS at 85% predicted MI-IR). However, the predicted heart rate for a given stage within the WI is based on a predicted (PMHR [220-age]) rather than measured MHR. The purpose of this study was to assess whether the WI, when calculated using MMHR would affect the prevalence of WI <0.80, and to assess whether the WI, when calculated using MIVIHR, is influenced by gender, age, RHR or aerobic capacity as measured by maximal oxygen uptake (V02 max). The sample included 522 self-referred adults (294 women, mean age 43 ± 11 years; 228 men, mean age 46 + 11 years) who completed a GXT test to volitional fatigue using the BSU/Bruce Ramp protocol. Exclusion criteria were use of betablockers, history of myocardial infarction, peak respiratory exchange ratio <1.0, or GXT time <6.0 minutes. WI was assessed at the end of 6th minute of the GXT with a value <0.80 considered evidence of CI. The mean WI from both methods was (PMHR = 1.088 +-0.20 vs MMHR = 1.063 + 0.16 (<.0001), with a correlation of 0.807. The prevalence of WI <0.80 was 8.0% and 4.4% for the PMHR and MMHR methods, respectively, which are considerably lower than the 14% and 12% reported by Lauer et al. Multiple regression. analysis revealed that gender, age, resting heart rate and V02 max were significantly associated with WI when derived using either predicted or measured MHR, (<.0001), however these variables only accounted for 13.6% (PMHR) and 15.6% (MMHR) of the variance in the multiple regression models. In conclusion, these results suggest a rather low prevalence of CI (WI<0.80) in this self-referred, adult population and support the notion that the measure of WI is relatively independent of age, resting heart rate and gender but appears to be directly associated with V02 max. / School of Physical Education

In an effort to determine the effects of carbohydrate feedings on exercise performance, ten male subjects performed intermittent exercise on an electrically braked cycle ergometer for a total of four hours. At the end of the four hours exercise, subjects performed a timed sprint ride to exhaustion. During the experimental trial, subjects ingested a total 172 g of solid carbohydrate. Repeated carbohydrate feedings improved the time to exhaustion at the end of the exercise, and consequently produced higher blood lactate levels. During the exercise, less muscle glycogen was used with carbohydrate feedings. Carbohydrate feedings, therefore, spare muscle glycogen during endurance exercise and improve sprint performance at the end of such exercise bouts.

This series of experiments was designed to examine various relationships between physical training and acid-base regulation in blood and muscle of man. The specific purposes of these studies were to 1) determine if the buffer capacity of blood differs between endurance trained and untrained males, 2) examine the effects of eight weeks of sprint training on the buffer capacity of blood and muscle, and 3) determine if a difference exists in the buffer capacity of blood and muscle between endurance trained and sprint trained males. Buffer capacity of blood, measured with an exercise titration of blood, was found to be not different between untrained and either sprint trained or endurance trained subjects. The buffer capacity of muscle, measured by observing the change in muscle pH created by known changes in muscle lactate, was found to be significantly greater in sprint trained subjects than both untrained and endurance trained subjects. Muscle buffer capacity was not different between untrained and endurance trained subjects. It was concluded that buffer capacity is atrainable entity but that its improvement is localized within muscle and is specific to the type of training employed.

Purpose. The purpose was to examine venous PO2, transcutaneous tissue PO2 (PtcO 2), and VO2max in a normobaric environment following a single HBO2 treatment. Methods. Ten moderately trained (VO2max = 57.6 mL&middot;kg-1&middot;min -1) males volunteered for the study. Baseline testing included measures of VO2max, PtcO2, and anthropometry. Subjects received two HBO2 treatments, which consisted of breathing 95% oxygen at 2.5 ATA for 90 min. Following the first HBO2 treatment (6.0 +/- 1.0 min), subjects performed a VO2max test. Following the second HBO2 treatment, leg and chest PtcO2 and venous PO2 were monitored for 60 min. Results . VO2max, running time, and peak La were not altered (p < 0.05) post-HBO2 treatment. Leg PtcO2 was lower (p < 0.05) and chest PtcO2 was unchanged following the HBO2 treatment compared to baseline values. Venous PO2 was lower in the first 3 min post-HBO2 treatment than subsequent values, but no other differences were found (p < 0.05). Conclusion. The results of this study show that a single HBO 2 treatment at 2.5 ATA for 90 min does not elevate venous PO2, PtcO2, or VO2max in a normobaric, normoxic environment.

No description available.

Graduation date: 1985

Thesis (M.S.)--University of Hawaii at Manoa, 2007. / Includes bibliographical references (leaves 53-57). / x, 57 leaves, bound col. ill. 29 cm

Physical exercise is frequently prescribed by clinicians and researchers as an effective stress reduction technique. There has been some research to support this assertion, however the research has been varied in its methodological rigor. The design problems, variations in exercise programs, and the use of a wide range of psychological measures have made results difficult to interpret. Additionally, the psychological benefits and underlying change processes have not been clearly delineated. The purpose of this study was to conduct a meta-analysis of the research in this area in an attempt to answer specific questions regarding the role of exercise in stress reduction. This meta-analytic approach was chosen because it permits the quantitative integration of findings of several studies and consideration of the variables that may influence the variance in study outcomes. The effectiveness of exercise as a treatment for stress, the type of exercise that was most beneficial, and the type of individual who gained the most from the exercise intervention was examined. The 61 effect sizes, which were calculated from 24 studies included in the meta-analysis, were coded along with other variables considered important. Study components such as design type, stress level, type of exercise program, program length, frequency of exercise sessions, attrition rate, psychological measure, composition of sample, gender, and study type were coded as independent variables. Effect size was the dependent variable. Analysis of variance revealed that exercise was an effective stress reducer, stressed people gained a greater stress reduction effect than minimally stressed people, and there were no differences between trait and state anxiety reduction from pre- to post-exercise program. In addition, a one-way ANOVA indicated that there was a significant difference between program lengths. Examination of the means revealed that an 8- to 12-week program was most effective in reducing stress. Although there was a greater effect size for unpublished studies than published studies, the pattern of change for each study type was similar. The significance of these results and recommendations for future studies are discussed. / Education, Faculty of / Curriculum and Pedagogy (EDCP), Department of / Graduate

The purpose of this study was to investigate work performance on a semi-defined, low calorie diet during daily periods of light and moderately heavy activity. Four male graduate students volunteered for the ten week study which was divided into five experimental periods. During Period 1 (control) the subjects received a balanced, normal diet of usual foods providing approximately 3600 calories per day and meeting the Canadian Dietary Standards for all nutrients. During this two week period, a "normal" level of activity was maintained. Period 2 consisted of ten days on a semi-defined low calorie diet with continued "normal" activity. The low calorie diet provided, approximately 1800 calories daily, plus one multiple vitamin pill. It met the Canadian Dietary Standards for all nutrients. Period 3 was a repeat of Period 1, two weeks during which the subjects received approximately 4000 calories, per day, of the control diet. Again, "normal" activity was maintained. Period 4 consisted of ten days of the same low calorie semi-defined diet as Period 2, with an additional daily energy expenditure, per subject, of approximately 500 calories. Period 5 was the same as Periods 1 and 3, two weeks of the control diet with "normal" activity. Several physiological variables were measured during the last two days of each experimental period to ascertain the effects of the treatment conditions on the cardiorespiratory and general fitness of the subjects. Strength measurements and maximal oxygen uptake determinations remained unchanged for the duration of the study, whereas, physical work capacity (PWC 170) decreased continually, beginning in the third experimental period. Total body weight decreased during Periods 2 and 4. Period 4, which involved increased physical activity caused slightly more weight loss than Period 2. Anthropometric measurements, body composition, and body density were only slightly changed, the changes paralleling the changes in body weight. Pasting blood samples were taken twice during each experimental period; midway through the period and on the last day. Twenty-four hour urine samples were also collected on the final day of each study period. Although some minor changes did occur, most biochemical parameters remained within normal limits. The blood glucose concentrations decreased during Periods 2 and 4 and plasma free fatty acid levels increased. Plasma cholesterol levels decreased during Periods 2 and 4, as did the hematocrit, hemoglobin, total serum protein, serum albumin, and blood urea nitrogen concentrations. Plasma Vitamins A and E, as well as the serum Vitamin C levels also decreased during Periods 2 and 4. Urinary thiamine excretion increased, possibly in response to the greater percentage of calories derived from endogenous fat stores Generally speaking, the low calorie diet situations were well tolerated by the subjects. Physiological measurements indicated a change only in physical work capacity, which decreased during the study. Biochemical determinations revealed definite alterations; however, most parameters remained within the normal limits. / Land and Food Systems, Faculty of / Graduate

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