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Motivation: The South-African deep level gold mining industry has adapted in many ways, as the pursuit for gold has led deep into the earth core, where rock face temperatures measure around 60°C. Ventilation adapted through engineering developments like refrigeration systems, creating cooler work environments to an extent. Despite these developments the risks of high ambient temperatures coupled with strenuous work and dehydration remains, leading to alternative methods of control that have to indicate whether employees have the necessary functional capacity to perform daily work tasks. Objectives: The objectives of this study were: to measure and compare the physiological effects of the tasks performed by workers in an underground mining environment; To measure the soundness of heart rate as a gauge of work stress in real-life work conditions, taking into account the stressors that influence it; to determine the efficacy of functional and physical work capacity assessments as a method of determining work readiness. Methods: A study group (n = 16) was chosen to represent the “most exposed” work population, all of whom have previously passed the functional work capacity and physical work capacity assessments. The assessments were repeated and the maximal oxygen uptake assessment was done. The participants were divided into two groups (n = 8) according to their work areas. Measurements were taken over a period of eight consecutive shifts. Each group was later divided into three groups as per the work they performed. Dehydration was determined through urine analysis and body weight changes. Heart rate was observed continuously through a heart rate monitor and oral temperature was measured on an hourly basis. Results: The shift durations seen during this study were much longer than the customary 8-hour work day. The mean HR results of group I, which was suspected of having the most strenuous work, were very similar to the results for group II and III. This group did, however, have the highest % heart rate ≥ 120 beats per minute and mean cumulative heart beats, group III having the lowest. All of the groups were found to be mildly dehydrated at the end of their shifts, the urine specific gravity indicating that the participants were generally already considerably dehydrated at the onset of the shifts. Group I was the only group whose mean heart rate had a statistically significant correlation (r ≥ 0.5) with % weight loss. There was a statistically significant (p ≤ 0.05) correlation between heart rate and mean oral temperature for all of the groups. The participants that passed the functional work capacity and physical work capacity assessments were found to have performed comparatively better during the real-time shifts than those that failed. Conclusions: Although there were several employees that had a high mean maximum heart rate, none of the mean heart rates were higher than the self-pacing rate of 110 beats per minute. This ability of self- pacing was seen in the way the participants were able to manage energy expenditure by alternating between heavy and lighter tasks. A great concern is the fact that all of the participants had a % weight loss (0.9 – 2.8% weight loss) indicative of mild dehydration after the shifts, on top of morning urine specific gravity samples (1.020 – 1.025) showing signs of considerable dehydration. Several correlations were found between the functional work capacity and physical work capacity assessments and maximum temperature, maximum heart rate and maximal oxygen uptake, suggesting a significant relationship between the real life situation and the homogenous laboratory setting. comparing the employees that passed the functional work capacity and physical work capacity assessment to those that failed, a marked difference was seen in their respective performances. The groups that passed had a lower mean heart rate and maximum heart rate and higher maximal oxygen uptake. It may, therefore, be concluded that the functional work capacity and physical work capacity assessments provide a valid evaluation of an individual’s work capacity and potential to cope with the varying demands of underground work. / Thesis (MSc (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2013.

Motivation: The South-African deep level gold mining industry has adapted in many ways, as the pursuit for gold has led deep into the earth core, where rock face temperatures measure around 60°C. Ventilation adapted through engineering developments like refrigeration systems, creating cooler work environments to an extent. Despite these developments the risks of high ambient temperatures coupled with strenuous work and dehydration remains, leading to alternative methods of control that have to indicate whether employees have the necessary functional capacity to perform daily work tasks. Objectives: The objectives of this study were: to measure and compare the physiological effects of the tasks performed by workers in an underground mining environment; To measure the soundness of heart rate as a gauge of work stress in real-life work conditions, taking into account the stressors that influence it; to determine the efficacy of functional and physical work capacity assessments as a method of determining work readiness. Methods: A study group (n = 16) was chosen to represent the “most exposed” work population, all of whom have previously passed the functional work capacity and physical work capacity assessments. The assessments were repeated and the maximal oxygen uptake assessment was done. The participants were divided into two groups (n = 8) according to their work areas. Measurements were taken over a period of eight consecutive shifts. Each group was later divided into three groups as per the work they performed. Dehydration was determined through urine analysis and body weight changes. Heart rate was observed continuously through a heart rate monitor and oral temperature was measured on an hourly basis. Results: The shift durations seen during this study were much longer than the customary 8-hour work day. The mean HR results of group I, which was suspected of having the most strenuous work, were very similar to the results for group II and III. This group did, however, have the highest % heart rate ≥ 120 beats per minute and mean cumulative heart beats, group III having the lowest. All of the groups were found to be mildly dehydrated at the end of their shifts, the urine specific gravity indicating that the participants were generally already considerably dehydrated at the onset of the shifts. Group I was the only group whose mean heart rate had a statistically significant correlation (r ≥ 0.5) with % weight loss. There was a statistically significant (p ≤ 0.05) correlation between heart rate and mean oral temperature for all of the groups. The participants that passed the functional work capacity and physical work capacity assessments were found to have performed comparatively better during the real-time shifts than those that failed. Conclusions: Although there were several employees that had a high mean maximum heart rate, none of the mean heart rates were higher than the self-pacing rate of 110 beats per minute. This ability of self- pacing was seen in the way the participants were able to manage energy expenditure by alternating between heavy and lighter tasks. A great concern is the fact that all of the participants had a % weight loss (0.9 – 2.8% weight loss) indicative of mild dehydration after the shifts, on top of morning urine specific gravity samples (1.020 – 1.025) showing signs of considerable dehydration. Several correlations were found between the functional work capacity and physical work capacity assessments and maximum temperature, maximum heart rate and maximal oxygen uptake, suggesting a significant relationship between the real life situation and the homogenous laboratory setting. comparing the employees that passed the functional work capacity and physical work capacity assessment to those that failed, a marked difference was seen in their respective performances. The groups that passed had a lower mean heart rate and maximum heart rate and higher maximal oxygen uptake. It may, therefore, be concluded that the functional work capacity and physical work capacity assessments provide a valid evaluation of an individual’s work capacity and potential to cope with the varying demands of underground work. / Thesis (MSc (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2013.

Diss. (sammanfattning) Stockholm : Tekn. högsk. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 6 uppsatser.

Diss. Linköping : Univ.

Diss. (sammanfattning) Stockholm : Karol. inst., 2006. / Härtill 5 uppsatser.

Thesis (Ph.D.)--Biomedical Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Oshinski, John N.; Committee Member: Fyfe, Derek A.; Committee Member: León, Angel R.; Committee Member: Skrinjar, Oskar; Committee Member: Taylor, W. Robert.

It is common practice for endurance athletes to manipulate training load prior to an important competition, known as tapering. An effective strategy aims to alleviate accumulated fatigue, whilst maximising physiological adaptation and facilitating a peak performance. Improvements in performance of 0.5 to 6.0% have been reported after a successful taper, a margin that could potentially have a dramatic influence on performance outcome at the elite level. This thesis explored the strategies currently employed by elite endurance athletes and investigated novel training manipulations during the taper to further enhance performance, to gain a more thorough understanding of the physiological mechanisms, and to identify a minimally invasive physiological biomarker capable of monitoring recovery status during the taper. Tapering strategies in elite endurance athletes were shown to be individualised and influenced by the preceding training load. Algorithms were developed, capable of explaining a large proportion of the variance (53-95%) in tapering strategy training variables (with the exception of interval volume), for a given pre-taper training load (Chapter III). A tapering strategy implemented using the algorithms was most likely to improve 1,500 m treadmill performance (ES = 0.53). When the intensity of final interval session was increased from 100% to 115% race speed, the effect on treadmill performance was unclear (ES = 0.22) and perhaps due to insufficient recovery to respond positively to the increased intensity interval session (Chapter IV). When continuous volume was reduced further (by 60%), the novel high intensity strategy was very likely to improve 1,500 m track performance (ES = 0.74), compared to the algorithm-derived taper (ES = 0.40) (Chapter VI). In middle-distance runners, training above race speed in the final days of the taper might be more beneficial than current practice, although training volume must be further reduced to compensate. It was possible to measure plasma concentrations of interleukin-6 and soluble interleukin-6 receptor from capillary samples (Chapter II), although these markers in addition to C-reactive protein, testosterone and cortisol were not sensitive enough to detect changes in recovery status during tapering (Chapters IV and V). Measures of muscle maximum voluntary contraction force (algorithm-derived taper: 9%; ES = 0.39; novel taper: 6%; ES = 0.29), and rate of force development (algorithm-derived taper: ES = 0.53; novel taper: ES = 0.26) improved in response to tapering (Chapter IV), and could represent alternative non-invasive markers of recovery and taper effectiveness to facilitate peak performance.

Orientador: Salomon Soriano Ordinola Rojas / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-12T15:05:14Z (GMT). No. of bitstreams: 1 Veiga_VivianeCordeiro_M.pdf: 4383215 bytes, checksum: 4ac235c87c9173ad91395fd7c6466208 (MD5) Previous issue date: 2008 / Resumo: Introdução A terapia de ressincronização cardíaca é uma opção efetiva nos pacientes com insuficiência cardíaca avançada. No entanto, 20 a 30% dos pacientes não apresentam benefícios à esta terapêutica. Critérios clínicos, eletrocardiográficos e ecocardiográficos têm sido estudados na tentativa de selecionar os pacientes que serão beneficiados com a ressincronização cardíaca, sendo o ecocardiograma um método utilizado tanto na seleção, quanto na avaliação e otimização desta terapêutica. Objetivo: O objetivo deste trabalho é analisar a utilização do ecocardiograma na avaliação da terapia de ressincronização cardíaca em pacientes portadores de insuficiência cardíaca refratária, no seguimento a curto prazo (dez dias) e após dois anos de evolução. Casuística e Método: Foram avaliados 20 pacientes com indicação de implante de marcapasso biventricular para terapia de ressincronização cardíaca no período de dois anos, sendo 16 (80%) do sexo masculino, com idade variando de 27 a 80 anos (59,70 ± 12,59 anos). A etiologia da cardiomiopatia era isquêmica em 10 pacientes (50%), chagásica em seis (30%) e idiopática em 4 (20%). Quinze pacientes encontravam-se em classe funcional III (New York Heart Association) e cinco em classe funcional IV no momento do implante do marcapasso. Foi aplicado o Questionário de Qualidade de Vida de Minnesota e realizado o teste de caminhada de seis minutos para avaliação das condições clínicas dos pacientes. Realizado ecodopplercardiograma bidimensional para avaliação da função ventricular, diâmetros cavitários, índice de performance miocárdica, estudo da dissincronia interventricular (avaliação do atraso eletromecânico entre os ventrículos esquerdo e direito) e intraventricular (análise pelo modo unidimensional e Doppler tecidual), da função diastólica e do grau da regurgitação mitral. Dez dias após o implante do marcapasso biventricular, foi repetida toda a avaliação inicial e, novamente, após dois anos. Resultados: Em dois anos, cinco pacientes (25%) foram à óbito, sendo que destes, quatro apresentavam etiologia chagásica. A duração média do complexo QRS era de 154,5±18,48 x 129,0±22,91 x 134,0±24,14 ms, respectivamente nos períodos pré-operatório, dez dias e dois anos de pós-operatório. Não houve alteração estatisticamente significante da fração de ejeção entre os períodos pré-operatório e dez dias, mas houve alteração significante entre os períodos pré-operatório e dois anos e dez dias e dois anos. No seguimento de dez dias, houve piora da dissincronia intraventricular avaliada pelo Doppler tecidual, assim como a pontuação no escore de qualidade de vida foi maior, no grupo óbito. Conclusão: A ecocardiografia é uma tecnologia em evolução e dos parâmetros avaliados, somente a avaliação da dissincronia intraventricular pelo Doppler tecidual após o procedimento, foi capaz de predizer a eficácia da terapia de ressincronização cardíaca, em relação à mortalidade. Não houve correlação entre os parâmetros ecocardiográficos e a melhora clínica de alguns pacientes. / Abstract: Introduction In the cardiac resynchronization therapy is an effective option for patients with advanced heart failure. However, 20 to 30% of patients did not show benefits to this therapy. Clinical criteria, electrocardiography and the echocardiography have been studied in an attempt to select the patients who will benefit from the cardiac resynchronization, and the echocardiogram is a method used in both the selection, as in the evaluation and optimization of this therapy. Objective: The objective of this study is to evaluate the use of echocardiography in the evaluation of patients undergoing cardiac resynchronization therapy for a period of two years. Patients and Methods: We evaluated 20 patients with the implantation of biventricular pacemaker for cardiac resynchronization therapy for over two years, and 16 (80%) males, ranging in age from 27 to 80 years (59.70±12.59 years). The etiology of cardiomyopathy was ischemic in 10 patients (50%), Chagas disease in six (30%) and idiophatic in 4 (20%). Fifteen patients were in functional class III (New York Heart Association) and five in functional class IV at the time of implantation of the pacemaker. We applied the Quality of Life Questionnaire of Minnesota and conducted the test of a six-minute walk to evaluate the clinical conditions of patients. Directed two-dimensional Doppler echocardiography for evaluation of ventricular function, cavity diameters, myocardial performance index, study of interventricular dyssynchrony (eletromechanical delay left ventricle - the right ventricle) and intraventricular (by way dimensional analysis and tissue Doppler), the diastolic function and degree of mitral regurgitation. Ten days after implantation of biventricular pacemaker, was repeated throughout the initial assessment and again after two years. Results: In two years, five patients (25%) were to death, and that these, four had Chagas disease. The average duration of the QRS complex was 154.5±18.48 x 129.0±22.91 x 134.0±24.14 ms, respectively in preoperative, ten days and two years after surgery. There was no statistically significant change in the ejection fraction between preoperative and ten days but there was significant change between periods preoperative and 2 years and 10 days and 2 years. Following ten days, the evaluation of intraventricular dyssynchrony by tissue Doppler and quality of life scores were significantly higher in the group died. Conclusion: The echocardiography is an evolving technology and the parameters evaluated, only the assessment of intraventricular dyssynchrony by Doppler tissue after the procedure was able to predict the effectiveness of the cardiac resynchronization therapy, in relation to mortality. There was no correlation between echocardiographic parameters and clinical improvement in some patients. / Mestrado / Mestre em Cirurgia