Thesis (PH.D.) -- Syracuse University, 2006 / "Publication number AAT 3251477."

Poor endothelial function can predict future cardiac events. Exercise is effective in modifying cardiovascular risk by enhancing endothelial function, although the amount necessary to see benefits is not clear. The first aim was to examine the effects of acute exercise to alter endothelial function and nitric oxide metabolites in overweight and sedentary individuals. Twenty-nine subjects were placed into 3 groups (Exercise, Inactive Control, Active Control). Sedentary and overweight subjects were assigned to the Exercise or Inactive Control Group, active normal weight individuals were assigned to the Active Control Group. The Exercise Group (N=15) came to the lab daily and had their resting blood flow, vascular resistance, conductance and peak reactive hyperemia measured in the calf. Measurements were made daily for 3 familiarization sessions and 24-hours following each of the 5 exercise sessions. The Exercise Group performed 60 minutes of cycling exercise for 5 days at 65% of their predicted maximal workload. Exercise was separated into 4 bouts of 15 minutes with 2 minutes of rest between each bout. Blood was drawn daily to determine if exercise altered plasma nitrate + nitrite concentration. These data were compared to the Inactive Control Group (N=5) who came to the lab for 6 consecutive days. The subjects in the Active Control Group (N=9) had 3 days of criterion measures to compare baseline differences with the Exercise Group. At baseline the Active Group had significantly lower mean arterial pressure and greater peak reactive hyperemia and nitric oxide metabolites than the Exercise and Inactive Control Groups. There were no significant main effects for time (5 days of exercise) or group (Exercise vs. Inactive Control) and no interaction of group vs. time. Thus, 5 days of exercise is not sufficient to alter calf vascular function or nitric oxide metabolites in sedentary overweight individuals. The second aim of this dissertation was to examine how 5 days of rest following the cessation of exercise would alter calf reactive hyperemia and nitric oxide metabolites. Following the exercise protocol, subjects were inactive for 5 consecutive days. There were no significant changes in criterion measures on any of the rest days.

Postural stability and rigidity are two of the major motor symptoms of Parkinson's disease (PD). Falls in PD tend to happen mainly during tasks involving turning and bending motions of the upper body. Although correlations between clinical measures of postural stability and axial rigidity have been reported, the nature in which axial rigidity affects postural control mechanisms in PD remains undetermined. The purpose of this dissertation was (1) to investigate changes in control of the upper body due to aging and PD and (2) to study the impact of these changes on the interaction of posture and manual control. In two experimental series, patients with PD as well as healthy younger and healthy older controls were tested under manipulations of upper body motion and proximity to stability boundaries while standing. Overall, PD patients were able to adapt their postural strategies to changing task demands and adequately performed the required tasks without falling. Across both experiments, a lack of adaptability in pelvis-trunk coordination as well as reduced segmental ranges of motion were observed in patients with PD. Patterns of center of pressure and trunk center of motion suggested that aging alone mainly affects control of reactive forces at the foot-support surface interface, while PD patients show additional impairments in controlling the upper body. PD patients showed both increased and decreased variability in movement patterns compared to controls, undermining the traditional notion that increased variability characterizes movement pathology and equates with postural instability. The results stress the importance of incorporating analysis of three dimensional upper body motions into the study of balance impairments. The findings overall suggest that in PD changes in adaptive control of upper body motion are related to changes in postural control mechanisms.

Includes bibliographical references (leaves 47-57). / The purpose of this thesis was firstly to review the possible relationship between chlorine in swimming pool water and exercise induced bronchospasm, and secondly to assess whether chlorine exposure during swimming provokes EIB in well-trained swimmers with and without a history of EIB.

Includes abstract. / Includes bibliographical references (leaves 55-79). / The effects of long-term participation in ultra-endurance exercise on the cardiovascular system have recently been the subject of much interest. It is well known that HRV, a marker of autonomic activity, is enhanced with long-term aerobic exercise training. However, after acute exercise, HRV is reduced, but recovers over time depending on the intensity of the prior bout of exercise. A limitation of previous research is that exercise bouts of only up to 120 minutes have been studied. A modified Stroop Task is a laboratory stressor to assess executive cognitive function by means of reaction time and accuracy. The resting HRV is directly related to these prefrontal neural functions, but the effect of an altered HRV on cognitive function has never been investigated. We determined the effects of an ultra duration (10 – 15 hours) exercise event on parameters of HRV and cognitive function during a Modified Stroop Task, 60 – 200 minutes after the 2007 South African Ironman Triathlon event (3,6km swim; 180 Km cycle; 42,2 Km run). 1 Female and 13 male competing triathletes (IRON; ages 33.7±7.9) and 7 control subjects (CON; 2 female and 5 males aged 42 ±4.5) completed a Modified Stroop Task before and after the event. The individual HRV parameters, heart rate (HR), respiratory frequency (RF), reaction time (RT) and % of mistakes made were recorded via the Biopac MP150WSW System (Goletta, California, USA). Data was transformed by auto regressive analyses (Biomedical signal analysis group, University of Kuopio, Finland) into LF (0.04 - 0.15 Hz) and HF (0.15 - 0.5 Hz) components. Additional calculations included %LF and %HF as well as the central or peak frequencies in both the LF and HF bands.

Bibliography: leaves 55-66.

Includes bibliographical references (leaves 105-115). / The aim of this prospective cohort study therefoew was to assess the morphological and blood flow changes in the Achille tendons of triathletes competing in the 2006 South African Ironman Triathlon. / abstract

Includes bibliographical references (p. 70-73). / The main aims of this dissertation are 1) to review the existing medical literature on the possible intrinsic and extrinsic risk factors for EAMC, and 2) to investigate risk factors that are associated with a self reported past history of EAMC in Ironman triathletes. The focus of this research is to increase the understanding of possible causes of EAMC, so that prevention and treatment strategies can be optimized.

Includes bibliographical references (p. 79-83). / The aim of this study was to compare which of the two commonly used treatment protocols for Exercise Associated Postural Hypotension (EAPH) (Trendelenburg with oral fluids ad libitum or intravenous fluids) result in quicker recovery and earlier discharge from the medical facility.

Includes bibliographical references (p. 120-138). / It is well documented that participation in ultra-endurance events such as the Ironman Triathlon, can be associated with the development of post-race water and sodium imbalances in athletes. Variants within genes that encode for proteins that regulate thirst have been shown to be associated with weight changes during participation in an Ironman Triathlon. Recent evidence of mutations within the arginine vasopressin 2 receptor (AVPR2) gene, which encodes a constitutively active receptor in the collecting tubules of the kidney, resulted in increased water reabsorption and hyponatraemia in two unrelated male infants. This suggests that serum imbalances and hydration status in individuals participating in an endurance event may also be, in part, controlled by variants withink the AVPR2 gene. The aim of this study was to investigate whether polymorphisms within the AVPR2 gene are associated with exercise-associated serum sodium and/or water imbalances in triathletes who particpated in the 2006 South African Ironman Triathlon.