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Biomedical subjects

D A Cunningham

Publications and source records attributed to D A Cunningham.

At least 181 records · Page 10Linked to original sources
PubMed1976

Comparison of methods to calculate cardiac output using the CO2 rebreathing method.

A comparison was made of methods used to calculate cardiac output by the indirect (CO2) Fick procedure (equilibrium method). Alternative methods for calculation of arterial PCO2, mixed venous PCO2, and conversion of gas tension to content were tested. Cardiac output values determined with a "corrected" equilibrium PCO2, to approximate mixed venous PCO2, were observed to be closest to cardiac output values determined on similar populations by the dye dilution method. Arterial PCO2 was best estimated from the Bohr equation using a dead space in exercise from prediction equations in the literature applicable to the populations under study. CO2 dissociation curves used to derive the veno-arterial CO2 content difference, were shown to differ considerably. For the present, the curve by McHardy [25], as modified by Jones (personal communication), and similar to the standard Comroe curve [5], was chosen.

Adolescent↗
PubMed1976

Health patterns associated with type A behavior: a managerial population.

Type A Behavior is a behavioral syndrome found to be related to coronary heart disease and characterized by excessive drive, ambition, and competitiveness. Managers from 12 different companies were examined for this syndrome and for a number of the known risk factors in coronary heart disease (blood pressure, cholesterol, triglycerides, uric acid, smoking, and fitness). Those individuals exhibiting extreme Type A Behavior (Type A) showed significantly higher blood pressure (systolic and diastolic) and higher cholesterol and triglyceride levels. A greater percentage of these individuals were cigarette smokers. On serum uric acid there were no differences. In each age group, Type A's were less interested in exercise, although differences in cardio-respiratory fitness were found only in the oldest age group. Type A Behavior also was related to age, education, company growth rates, and stress symptoms. Overall, the Type A1's were found to be higher on a number of risk factors known to be associated with coronary heart disease. With regard to the Type A2's (individuals with less developed Type A Behavior), the findings were not conclusive.

Administrative Personnel↗
PubMed1976

Effect of training on plasma catecholamines in post myocardial infarction patients.

Exercise induced plasma catecholamine levels, of post myocardial infarct patients, were compared before and after a 27 week training program in two groups. Heavy Intensity Exercise (H.I.E.) and Light Intensity Exercise (L.I.E.). The men (age 38-54 years) were exercised on a bicycle ergometer at constant submaximal work loads (test load) and to a symptom limited maximum work load, both before and after the training program. Forearm venous samples were obtained after 30 minutes rest and within 3 minutes of completion of the test load. After training a significant increase in both maximum work load and heart rate (P less than 0.05) was observed in the H.I.E. group. At the test load these individuals had a small (6%) decrease in heart rate. No significant changes were observed in the L.I.E. group at submaximum or maximum exercise. Prior to training, exercise resulted in a significant increase in norepinephrine (NE) with no change in epinephrine (E). Training resulted in a significant reduction (P less than 0.05) in the NE response at the test load of the H.I.E. group while no change was found in the L.I.E. group. Endurance jogging reduced the sympathetic response to moderate exercise.

Adult↗
PubMed1976

The cardiopulmonary capacities of young hockey players: age 10.

The cardiopulmonary capacities of 15 selected 10 year old ice hockey players were determined during a discontinuous steady-state bicycle ergometer test. During the test, heart rates, minute ventilation and oxygen uptake were monitored and the peak values at maximal capacity were recorded. Blood was collected from the median cubital vein after each maximal exercise for lactate analysis. These boys represented a select group of highly successful young hockey players. They had been involved in organized hockey for a mean of 4.4 years, 2.9 of which had been spent in a competitive league. The team has ranked 3rd in the Ontario Championships. The maximal oxygen uptake was 56.6 ml/kg-min, a value much higher than reported for healthy inactive boys and close to values reported for young athletes in other sports. Mean maximal minute ventilation reached 64.5 l/min (1.84 l/kg-min). The tests on these athletes were carried out on two separate occasions, 48 hours apart. The test-retest correlations for VO2 max was high (r = 0.81). Only the reliability of the lactate determinations was low (r = 0.24). None of the differences between the mean values for the measurements made at the first and second exercise tests were significant.

Child↗
PubMed1975

A controlled prospective study of the effect of endurance training on the recurrence rate of myocardial infarction. A description of the experimental design.

A multicenter prospective study has been designed to determine whether participation in an exercise program which produces a significant training effect will affect the recurrence rate in men who have survived an initial myocardial infarction. The control group consists of subjects who participate in a program involving low intensity activities designed to avoid a significant training effect. The subjects will be followed for a period of 4 years and a reduction of 50 per cent in the risk of recurrence will be considered clinically significant. The criteria for entry, the method of allocation, the structure of the exercise program and method of assessing cardiorespiratory fitness are described.

Angina Pectoris↗
PubMed1975

Effect of training on cardiovascular response to exercise in women.

Seventeen women (mean age 31 yr) participated in a training program divided into an initial 9-wk period and a subsequent 52-wk period, during which time 6 continued to exercise and the remainder detrained. Improvements in VO2max were significant (+34%) during the initial 9 wk and small (+5%) for the final 52 wk. Four women who stopped training showed a decrease in VO2max (-10%) during the last phase. During the initial 9 wk, central adaptation was important, with SV showing an increase of 28% at 80% VO2max. Peripheral adaptation (a-v O2 difference) was unchanged. Subjects who trained an additional 52 wk showed a slight drop in SV at submaximal work loads from the initial increase following the first 9 wk. When compared with the initial test the change at 9 wk in peripheral adaptation was a small and nonsignificant rise, followed by a significant increase at 61 wk. Women who are very unfit initially (predicted VO2max of 28 ml/kg-min), apparently adapt to the initial training with a central change followed by a much stronger peripheral adaptation during a longer training program.

Cardiac Output↗
PubMed1975

Cardiorespiratory response to exercise on a rowing and bicycle ergometer.

Eight experienced oarsmen and five inexperienced subjects performed a multi-stage exercise test on a rowing and bicycle ergometer. Oxygen uptake, heart rate and minute ventilation were observed on both exercise modes from light to maximal exercise. Although the VO2 max values were slightly higher on the bicycle ergometer (6.0% and 4.0% for the oarsmen and inexperienced subjects) differences were not significant (P greater than 0.01), nor consistent in all subjects. Max heart rates and lactate levels were similar on both exercise modes. The VE/VO2 ratio, however, was consistently higher on the bicycle than on the rowing ergometer at maximal exercise for all subjects (7.2% and 8.2% for the oarsmen and inexperienced subjects, (P smaller than 0.01). Apparently, the development of VO2 max on the bicycle ergometer was characterized by a larger VE/VO2 when compared with the rowing ergometer. The cramped position of the body while rowing appears to constrict the abdominal muscles, which may limit their ability to aid in the expiratory phase of the breathing cycle. The forcing up of the abdominal viscera in this position may also constrict the action of the diaphragm during inspiration.

Adult↗