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The purpose of this retrospective study was to determine if physiological performance measures were associated with staying in or dropping out of a medically supervised exercise program. In a retrospective file analysis, three subject groups of 35 subjects each were defined by their length of participation in the program. One group, the early drop outs, included subjects who participated in the program for a period of less than six months, another group, the late drop outs, participated for 6-12 months, and the third group, the compliers, was comprised of subjects who complied with the program beyond one year. Measurements were made on the following variables at entry and again after six months of participation: maximal oxygen uptake, resting heart rate, resting blood pressure, serum cholesterol and body weight. U sing analysis of variance for paired groups, the three groups were found not to differ on any performance variable at entry (p > .05). No significant differences were observed between the late drop outs and compliers when identical performance measures were compared at the time of the six month GXT. A paired t-test analysis to determine physiological changes within both the late drop outs and complier groups revealed that neither group had made significant improvements in the physiological indicators over the six month period, except in the oxygen consumption measurement for both the late drop outs and the complier groups, / Master of Science

The 2 in VO2 is in subscript. / Thesis (MSc)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: Please see fulltext for abstract / AFRIKAANSE OPSOMMING: Sien asb volteks vir opsomming

The purpose of this paper was to monitor the heart rates of-first, third, and fifth grade students during physical education classes to determine if the classes contribute to improvement in cardiovascular fitness levels. The study determined the average heart rate of students in physical education classes and determined the percent of time the heart rate remained in, above, and below a predetermined heart rate range of 140 to 180 beats per minute.Students from seven schools were involved in this study which included: 338 first graders, 236 third graders, and 217 fifth graders. Each school was visited three times.The measurement of heart rates was accomplished by placing a heart rate monitor on each student during their regular physical education class. The results indicated that the average heart rate for all first graders was 142.28 beats per minute (bpm), for all third graders was 141.68 bpm, and for all fifth graders was 142.85 bpm. The percentage of time spent in the pre-determined heart rate range for first grade students was 39.98%, third grade was 37.78%, and 40.64% for fifth grade. The percentage of time spent above the pre-determined heart rate range for first grade was 15.59%, 15.76% for third grade, and 13.91% for fifth grade. The percentage of time spent below the predetermined heart rate range for first grade was 43.99%, for third grade 46.32%, and 47.00% for fifth grade. The above findings revealed that the average heart rates did increase, although when further examining the percentage IN, ABOVE, and BELOW the pre-determined heart rate range the figures indicated that heart rates were not maintained at an appropriate level of intensity for the adequate time needed to increase cardiovascular fitness levels. If cardiovascular fitness is a goal in these classes, changes in class drills and games will be required to accomplish this goal. / School of Physical Education

Electrodermal responding (EDR) and heart rate (HR) were assessed for seven subjects participating in a reaction time task consequated with monetary bonuses (250, 100, and 10), monetary penalties (250,100, and 10), and a monetary neutral value (00). Unlike previous research employing group designs and a tonic measure (i.e., mean over long periods of time), this study utilized a single-subject design and a phasic measure (i.e., mean over 2-s intervals). Heart rate data was too variable for meaningful analysis. EDR data showed that the peak levels of EDR were higher for penalties than for the corresponding values of bonuses (e.g., -250 vs. +250) for most subjects. Similarly, peak levels of EDR were generally higher during sessions in which consequences were presented than in sessions during which consequences were absent.

This study concerned the effect of ethanol on cardiac activity and brain respiration in chick embryos. Ethanol dosages tested ranged from 1.0 mg to 4.0 mg/g weight. Each experiment lasted at least 150 minutes. Cardiac activity in terms of total waveform energies was integrated and printed out for plotting and analysis. The embryonic heart rates were simultaneously determined from physical graph tracings. The embryonic brain respiration was measured using a differential microrespirometer. The effect of ethanol on cardiac activity was one of slight (10 to 13), but statistically significant (p<.05) rate depression. The brain slices exhibited a marked, immediate, and irreversible decrease (39 to 89%) in oxygen consumption at both ethanol dosages. The data indicated that chick embryonic brain tissues were more susceptible to alcohol effects than cardiac tissue. Therefore, the mental abnormalities seen in the offspring of alcoholic mothers may be more cerebral in nature than cardiovascular.

This study presents the findings of an investigation of the effects of two different treatments, progressive relaxation and cerebral electrotherapy, on heart rate. With progressive relaxation, the subject relaxes by following instructions. With cerebral electrotherapy, relaxation is due to an external source of stimulation. Decreases in heart rate for subjects receiving progressive relaxation were compared with decreases for subjects receiving cerebral electrotherapy. A placebo group was used to evaluate the effects of both treatments independently. While decreases in heart rate were observed for both treatments, only progressive relaxation produced decreases significantly greater than those of the placebo group. However, decreases in heart rate produced by progressive relaxation were not significantly greater than decreases produced by cerebral electrotherapy.

Depression is an independent risk factor for morbidity and mortality in patients with coronary artery disease (CAD). Altered autonomic nervous system (ANS) activity, a common feature of depression, is also a risk factor for cardiac events in patients with CAD. Heart rate variability (HRV) reflects ANS activity, and reduced HRV predicts morbidity in cardiac populations. The purpose of this study was to determine whether differences in HRV exist between depressed and nondepressed patients with CAD. Twenty-one depressed inpatients, with angiographically documented CAD were retrospectively matched to 21 nondepressed CAD patients by sex, age, and smoking status. Demographic, medical, psychological interview data, and 24-hour ECG recordings were obtained. Depressed subjects had significantly lower HRV, or trends toward lower HRV, than nondepressed subjects, even after controlling for severity of CAD. Subject groups did not differ on left ventricular ejection fraction, history of myocardial infarction, or any other relevant medical variable assessed. These results suggest that depression is associated with decreased HRV in patients with CAD, and may help to explain the increased rates of cardiac events observed in CAD patients with depression.