Fatigue is a familiar and commonplace occurrence, but attempts to investigate the nature of fatigue have been inconclusive. Following more than a hundred years of extensive research, the construct is still ill-defined. This has resulted in a series of different strands of research, producing results concomitant with each researcher's own idea of what constitutes fatigue. Two central questions remain unresolved: (1) what sort of a construct is fatigue? and (2) should fatigue be conceptualised as a single, one dimensional state, generated by a range of different conditions, or a multidimensional state, incorporating a number of distinct but related states? There is an implicit assumption within the literature (and every-day language) that there is more than one 'type' of fatigue. However, there is currently no theoretical model which outlines the types of fatigue which should be incorporated in a theoretical framework and which explains the relationships between these fatigue types. The work presented in this thesis represents an attempt to address these issues using both psychometric and experimental approaches. Preliminary work investigated the psychometric basis for a unitary or multidimensional construct. This separately addressed the constructs of state and trait fatigue and, on the basis of the findings, state and trait multiple fatigue questionnaires were developed. A series of four experiments were then carried out which manipulated different types of work to facilitate an investigation of the dynamic development of fatigue. The first three experiments focused on the separate effects of mental and physical fatigue, and the final experiment considered the nature of their interaction.Both experimental and psychometric analyses supported the proposition of a multidimensional construct. The evidence in support of a multidimensional construct of trait fatigue was particularly strong. However, while the evidence in support of a multidimensional construct of state fatigue was less convincing, the experimental manipulations of different types of workload did produce states of fatigue that were subjectively different and also different patterns of fatigue after-effects.

The use of quality of life instruments to evaluate the effect of cancer and its treatment on individuals has increased but the process by which the patient comes to make these quality of life evaluations has not been addressed. Earlier studies have shown the reporting of physical symptoms and the evaluation of one's health to be related to negative affect. The purpose of this study was to investigate whether the relationship between negative affect and the evaluation of ones health would remain the same in a group of cancer patients, when a major disease and treatment symptom, fatigue was controlled for. The current study found no relationship between negative affect and the evaluation of health once fatigue was controlled for. Negative affect and fatigue were found to be moderately correlated and fatigue accounted for a large proportion of the variance in the quality of life domains of physical, functional and emotional well-being. Both empirical and theoretical issues are discussed. / Department of Counseling Psychology and Guidance Services

Studies assessing the reliability of the Borg rating of perceived exertion (RPE) scale for regulating exercise training intensity have reported mixed results. Differences in experimental designs and analytical techniques make it difficult to compare results. The purpose of this study was to examine the reliability of perceptually-based treadmill (TM) exercise. Eleven subjects (42.5 ± 19.5 yrs) completed a maximal test (GXT) and 3 RPEproduction trials (PT) on a TM. Each PT consisted of two 10-minute bouts where subjects selected speeds and grades to elicit an intensity equated with an RPE of 11-12 (RPE-L) and RPE of 15-16 (RPE-H). Speed and grade, heart rate (HR), oxygen uptake (V02), and ventilatory equivalent for oxygen (VE/V02) were assessed throughout the GXT and the last 3 minutes of each PT. Blood lactate concentration (BLC) was assessed at RPE-L and RPE-H during the GXT and at the completion of each PT intensity. Reliability was assessed using an ANOVA with repeated-measures, intraclass correlations, and absolute differences (ABS A) across the PTs at each intensity. No significant meangroup differences were noted in any of the physiological variables at either intensity across the PTs. Reliability coefficients were higher for the selected workload and the metabolic measures than for HR or BLC. Reliability increased across trials for all measures, and as a function of intensity for V02 (L = 0.91 & H = 0.98), HR (L = 0.60 & H = 0.84), and BLC (L = 0.50 & H = 0.64). Mean ABS A evaluated the inter-trial reliability for HR (bpm) and V02 (METS) at the low intensity PT 1 vs. PT2 = 013 bpm; A3.3 METS, PT 1 vs. PT3 = 010 bpm ; A3.3 METS, and PT2 vs. PT3 = A7 bpm; 01.6 METS and the high intensity PT 1 vs. PT2 = 011 bpm; A2.5 METS, PT 1 vs. PT3 = 011 bpm; A3.4 METS, and PT2 vs. PT3 = A9 bpm; A2.2 METS, respectively. Mean ABS A decreased for HR and V02 between PT2 vs. PT3. These data suggest that reliability of perceptually-based TMexercise varies among physiological measures and various analytical techniques, and individual variation in physiological data across PTs should be considered prior torecommending RPE for the self-regulation of exercise. / School of Physical Education

The use of quality of life instruments to evaluate the effects of cancer and its treatments on patients has increased, but understanding the roles that fatigue and depression play on quality of life is still complicated. Earlier studies have examined the individual effects on the quality of life of cancer patients. The purpose of this study was to investigate whether gender is related to the effects of fatigue and depression on quality of life. This study also examined the interactional effects of fatigue and depression on quality of life. The current study found no significant differences on reports of quality of life between genders. Additionally, this study found that depression and fatigue were moderately correlated. Depression and fatigue were also found to account for a proportion of the variance in the quality of life domains of physical, functional, and emotional wellbeing. However, the interaction effects were minimal, but were significant predictors of total quality of life in females, but not male, cancer patients. / Department of Counseling Psychology and Guidance Services

This post-positivist research study explored the possible relationship between Chronic Fatigue and Immune Dysfunction Syndrome (CFIDS) and the presence of underlying psychological and emotional issues. An exploratory design with naturalistic methods of inquiry was utilized to investigate whether the presence, or absence, of these issues had any impact on the overall disease process.