The appropriate intensity of exercise needed to reduce the risk of hypoglycemia (≤3.9 mmol/L) in persons with type 1 diabetes (T1D) is not known. Ten participants with T1D performed four exercise sessions on a treadmill lasting 45 minutes: a control condition at 45-55% of heart rate reserve and three high intensity sessions at 70, 80, and 90% of heart rate reserve. A blinded continuous glucose monitor was used to measure time spent ≤3.9 mmol/L and glucose variability in the 12 hours following exercise. There were no significant changes in the percentage of time spent ≤3.9 mmol/L (p=0.58) and glucose variability as measured by mean absolute glucose change (p=0.53) and continuous overall net glycemic action (CONGA1: p=0.95; CONGA2: p=0.90; CONGA4: p=0.72) between the sessions. High intensity exercise at 70, 80, and 90% of HRR does not significantly reduce the amount of time spent ≤3.9 mmol/L or glucose variability compared to the 45-55% session alone. / October 2015

Introduction: People with asthma suffer from lower fitness levels when compared to their peers. The abnormal respiratory response to exercise, known as exercise induced bronchoconstriction (EIB), in the majority of people with asthma is a barrier to improving fitness levels. EIB severity can be increased with airway inflammation, which can be measured by exhaled nitric oxide (eNO). One exercise protocol, high intensity interval exercise (HIIE), may decrease the risk of developing EIB in people with asthma. HIIE warm up studies have demonstrated that HIIE is feasible and reduces the incidence of EIB in subsequent exercise bouts. HIIE may be ideal for people with asthma because it can decrease the duration of high ventilation that can trigger EIB, and improve their fitness levels. The purpose of this study is to compare the acute respiratory effects of traditional constant workrate exercise to a novel HIIE protocol in adults with asthma. Methods: 5 females and 2 males with asthma were recruited to perform two randomly assigned exercise protocols: HIIE (30 seconds of 140% the peak workrate and 90 seconds at 20%) and constant workrate exercise (CWR) (60% peak workrate). Workrates were determined by a peak cardiopulmonary exercise test. Measures of pulmonary function and airway inflammation were done pre and post exercise protocols. During exercise protocols, operational lung volumes, heart rate, rating of perceived exertion (RPE) was obtained. Results: FEV1 decreased significantly in both exercise protocols (HIIE 3.91± 0.65 to 3.33 ± 0.61 vs. CWR 3.90 ±0.50 to 3.09 ± 0.63). eNO measurements decreased after both exercise protocols (HIIE 40.4± 34.8 vs. CWR 42.1 ± 36.3. Conclusion: FEV1 and eNO findings are similar in HIIE and CWR exercise in adults with asthma, therefore, the novel HIIE is a feasible exercise protocol to help improve fitness levels of adults with asthma.

No description available.

In light of the current global prevalence of overweight and obesity, the associated health risks, and the continuing adoption of sedentary lifestyle, this thesis investigated some of the factors that contribute to exercise adherence, directly comparing high-intensity whole body interval training and continuous endurance training. 68 inactive university aged adults (Age: 21.4±3.4 yrs, BMI: 25.6±4.6 kg/m2, VO2peak 40.1±5.7 ml/kg/min) were randomized into one of three groups; a non-exercise control, whole body high intensity training, or continuous endurance training. Aerobic capacity measurements, time to completion trials, muscular endurance, and core strength measures were taken at pre, post and follow up testing sessions. Psychological questionnaires were also administered during exercise as well as throughout the study. Following the intervention both exercise groups demonstrated equivalent improvements in aerobic performance, with only the interval group experiencing improved muscular and core endurance. After the 2-month follow up testing sessions the interval group lost all aerobic and core adaptation, with endurance only experiencing a partial loss. This finding indicates that the interval group did not adhere to exercise at a level that was high enough to preserve the adaptations associated with training. This finding is further supported by the psychological factors measured throughout this study, including acute affect, enjoyment and intentions to engage in future exercise. / Thesis (Master, Kinesiology & Health Studies) -- Queen's University, 2013-10-31 15:08:15.524

The hyperbolic power-duration relationship for high-intensity exercise is defined by two parameters: an asymptote (critical power; CP) reflecting the highest sustainable rate of oxidative metabolism, and a curvature constant (W'), which indicates a fixed amount of work that can be completed above CP (W>CP). According to the CP model of bioenergetics, constant work rate exercise above CP depletes the capacity-limited W' with fatigue occurring when W' is completely expended. The complete depletion of W' has been reported to occur when VO2max is attained and a critical degree of muscle metabolic perturbation (decline of finite anaerobic substrates and accumulation of fatigue-related metabolites) is reached. However, while the CP model is effective at predicting metabolic perturbation and the tolerable duration of severe-intensity constant work rate (CWR) exercise, it is unclear if metabolic perturbation and exercise performance can be explained by the CP model when different methods of work rate imposition are applied. Therefore, the purpose of this thesis was to: 1) investigate the efficacy of the CP concept to predict performance in exercise tests using different work rate forcing functions; and 2) explore whether the physiological bases for W' are consistent across different methods of work rate imposition. In study 1, compared to severe-intensity CWR exercise, the tolerable duration of intermittent severe-intensity exercise with heavy- (S-H) moderate- (S-M) and light-intensity (S-L) ‘recovery’ intervals was increased by 47%, 100% and 219%, respectively. W>CP (W') was significantly greater by 46%, 98%, and 220% for S-H, S-M and S-L, respectively, when compared to S-CWR, and the slopes for the increases in VO2 and iEMG were progressively lowered as the recovery work rate was reduced. In study 2, both the VO2max and W>CP were similar across incremental cycling protocols that imposed a fixed ramp rate and cadence (4.33 ± 0.60 L•min-1; 14.8 ± 9.2 kJ), a fixed ramp rate with cadence self-selected by the subjects (4.31 ± 0.62 L•min-1; 15.0 ± 9.9 kJ) and a step incremental test where subjects were instructed to select power output according to prescribed increments in ratings of perceived exertion (4.36 ± 0.59 L•min-1; 13.0 ± 8.4 kJ). In study 3, the VO2max and W>CP were also not different across a 3 min all-out cycling test (4.10 ± 0.79 L•min-1; 16.5 ± 4.0 kJ), cycling at a constant work rate predicted to lead to exhaustion in 3 min until the limit of tolerance (4.20 ± 0.77 L•min-1; 16.6 ± 7.4 kJ) and a self-paced 3 min work-trial (4.14 ± 0.75 L•min-1; 15.3 ± 5.6 kJ). In study 4, after completing severe-intensity exercise (>CP) to exhaustion, muscle homeostasis ([PCr], pH, [ADP] and [Pi]) returned towards baseline and subjects were able to exercise for at least 10 min at a heavy-intensity work rate (<CP); however, when the work rate was lowered but remained in the severe-intensity domain (>CP), muscle metabolites ([PCr], pH, [ADP] and [Pi]) did not recover and exercise tolerance was severely limited (39 ± 31 s). Finally in study 5, during severe-intensity intermittent knee extension exercise, the tolerable duration of exercise was 304 ± 68 s when 18 s recovery was allowed and was increased by ~69% and ~179% when the intermittent recovery periods were extended to 30 s and 48 s, respectively. The increased exercise tolerance with longer recovery periods occurred in concert with increased W>CP (3.8 ± 1.0 kJ, 5.6 ± 1.8 kJ and 7.9 ± 3.1 kJ for the intermittent protocols with 18, 30 and 48 s of recovery, respectively) and a delayed attainment of critical intramuscular metabolite concentrations ([PCr], pH, [ADP] and [Pi]). Therefore, the results of this thesis demonstrate that fatigue during various high-intensity exercise protocols is influenced by the capacity to complete work above the CP (W') and that W' depletion is linked to the attainment of VO2max and the attainment of critical levels of intramuscular [PCr], pH, [ADP] and [Pi]. These findings suggest that the CP model can be adapted to predict the degree of metabolic perturbation and exercise performance across a range of exercise settings in humans.

The rising incidence of small, asymptomatic renal tumours discovered usmg abdominal imaging during the investigation of unrelated symptoms has fuelled the desire for new therapies which avoid surgical excision. Extracorporeal High Intensity Focused Ultrasound (HIFU) was proposed as one of these modalities but so far clinical research has been ,~." inconclusive. The present work was designed to improve these clii teal outcomes through the conduct of further clinical trials, laboratory based research and the translation of new technology into existing HIFU devices. A Phase II clinical trial of patients (n=13) with newly diagnosed <4cm renal tumours (clinical stage T1a) was designed, peer reviewed and received ethical approval (Ox REC 09/H0606104). Ten of 13 patients underwent renal HIFU using a clinical HIFU device (Model JCIJC200, HAIFU, China). One patient could not be treated due to poor tumour visualisation after anaesthesia and two patients could not be treated as they became unwell before or during anaesthesia. Histological evidence of HIFU ablation in either tumour or normal renal parenchyma was seen in all ten patients. Evidence of sub-total tumour ablation was seen in 8/10 of patients. Grade 1 «50%), 2 (50-90%) & 3 (90-99%) ablation was achieved in 4/10, 3/1 0 & 3/1 0 patients respectively but complete (100%) tumour ablation was not possible. HIFU treatment caused minimal morbidity - no Grade III- V (Clavien-Dindo) complications related to HIFU treatment occurred. Grade I skin pain and induration was seen in 9/1 0 patients; Grade II skin pain occurred in a single patient. Patient demographics, imaging and tumour characteristics were used to design parameters to improve patient selection for renal HIFU. The tumour location, thickness of peri-nephric fat and renal nephrometry score were useful predictors of successful screening for treatment. Page /ii Dr R. W Ritchie Nutiield Department of Surgical Sciences - TT 2012 Abstract Diligent use of these factors could limit unnecessary treatments and Improve ablation outcomes. , It is well known that ultrasound imaging of small renal masses can be challenging. Ultrasound imaging often deteriorates further during HIFU as the abdominal wall and fat tissues swell and cause increased attenuation. This loss of imaging quality was clearly demonstrated in this clinical trial and resulted in the early termination of treatment, before ,#,J' ... ~ .•.. endpoints were reached, in a number of cases. The current clinical method for monitoring the success of HIFU ablation using hyperecho analysis of B-mode ultrasound images is also questionable. Laboratory based studies using ex-vivo bovine liver subjected to HIFU confirmed that hyperecho monitoring had low sensitivity, predictive values and overall accuracy. A novel method of HIFU monitoring - passive mapping of the emissions received from acoustic cavitation activity and other sources of non-linearity during HIFU treatment - is believed to represent a significant opportunity to improve feedback. This technique uses the passively received signature of cavity activity which, when time-reversed, gives high- resolution images of the precise location of the activity. Laboratory-based ex-vivo work, using a commercially available ultrasound system (z.one, Zonare, USA), demonstrates its superiority over hyperecho monitoring. Indeed, thresholds could be applied to successfully predict HIFU ablation with high sensitivity and specificity. This technique was successfully translated into the clinical setting through the design of a Passive Acoustic Mapping (P AM) device. Custom-built receiving elements were applied without limiting the function of the existing HIFU devices. Both pre-clinical and ethically- Page [iii Dr R. W Ritchie Nuffield Department of Surgical Sciences - TT 2012 Abstract approved clinical studies demonstrated its safe integration without significant impact on the device energy output or treatment accuracy. Using similar passive beamfonning algorithms, acoustic cavitation activity was successfully mapped and corresponded with the location of thermal ablation in both ex-vivo tissue phantoms and during clinical HIFU therapy. ,~-' It is believed that the development of new patient selection paral~~tel's will elimil?ate target those patients who are most suitable for renal HIFU - small tumours, minimal peri-nephric fat & low nephrometry score .. The use of P AM will lead to a significant improvement in the efficacy of treatment. It can be successfully applied to existing devices and predicts the location and extent ofHIFU ablation with greater accuracy that existing techniques.

No description available.

Regensburg, Univ., Diss., 2008

High intensity proton synchrotrons provide beams for several types of facility around the world, including spallation neutron sources and high energy physics experiments. The defining feature of these particle accelerators, that of intense beams, is tightly coupled to what limits the intensity, which is the controlled loss of beam particles. Many different factors contribute to beam loss. Beam will be lost on injection to a synchrotron and may be lost on extraction or in transfer lines. Non-linearities in the accelerator lattice can introduce driving terms for resonant beam behaviour. Collective effects between the beam particles and with the beam environment modify the single particle behaviour considerably. High intensity loss that occurs in the transverse plane, due to space charge and image fields, was investigated. The rapid cycling synchrotron at the ISIS Spallation Neutron Source in the UK was the focus for all of the work. The ISIS Synchrotron has many particular features which were described. One such feature is the conformal rectangular vacuum vessel, which takes the shape of the design beam envelope with certain modifications. This vacuum vessel has a complex effect on beam image fields. Numerical tools to study the space charge and image fields at ISIS were created and reported. The tools included two Poisson solvers to study space charge and images which were benchmarked against commercially available algorithms. A two dimensional particle-in-cell tracking code was created using the space charge solvers in combination with either a smooth focusing lattice model or one which generated Twiss matrices. A variety of diagnostic tools were available. A survey of existing analyses for pencil beams in parallel plate and rectangular geometry was made. Results from the analysis were then compared with two dimensional simulations with round uniform beams in rectangular geometry. Differences and extensions to the analysis were summarised. Coefficients for higher order image terms were defined and tabulated. The two dimensional nature of the image field was discussed and values for the coefficients for certain higher order terms identified in the plane orthogonal to the beam offset. Solutions for closed orbits produced with single and harmonic kicks at low and high intensity were discussed and simulated. A model was proposed which included the higher order image coefficients produced by the closed orbits. A single particle model was then explored which obtained resonance conditions from the closed orbits and image coefficients. The effect of self-consistent coherent motion on the results was discussed. Particle-in-cell beam tracking simulations were used to explore the results of this analysis numerically. Image resonances were found and described for a variety of simulation parameters starting with a smooth focusing lattice and uniform density beam, then progressing to more realistic cases including waterbag beams, alternating gradient lattices and conformal vacuum vessels. Image resonances described by the models were reported as were others that needed further explanation. Their possible impact for ISIS was discussed. New experiments with coasting beams at ISIS were carried out to explore the relationship between tune and beam loss at low intensity. Such experiments are a vital first step to understanding high intensity behaviour. It was shown that ISIS has existing lattice nonlinearities (some known, some unknown) which will need to be taken into account for high intensity experiments and simulations. Finally this work was put into context by examing specific transverse space charge effects for a proposed ISIS upgrade and including ideas developed throughout the thesis. Estimates were made of the strength of space charge effects and emittance scaling using conventional methods. The particle tracking tools developed for the thesis were then used to study beam behaviour with lattice gradient errors, the effects of closed orbits and changes to the working point. The transverse calculations and simulations suggested that the upgrade was feasible.

Ageing is associated with a decline in health. Physical activity is known to attenuate this decline; however a large amount of the general population does not participate in the recommended amount of physical activity. Time is reported in middle-aged and elderly populations as a major barrier to exercise participation. Therefore time-efficient and effective exercise paradigms are required to encourage engagement in physical activity, improve health and reduce the risk of disease. The aim of this thesis was to investigate the potential of using high intensity training (HIT) as an exercise paradigm to promote optimal ageing. Seventy seven participants (age range 35-75 years) were recruited to take part in HIT protocols consisting of 10 x 6 second sprints interspersed with a minimum of 1 minute recovery. Prior to taking part in the training participants underwent a series of baseline measures which included physical function tests, predicted aerobic capacity, oral glucose tolerance test, fasting lipid profile, body composition and blood pressure. After 6-10 week of training, participants were retested to determine the effectiveness of HIT. Following 6, 8 or 10 weeks of HIT, physical function was significantly improved by 9-29% in both middle aged and elderly populations. Aerobic capacity was increased by 10.5% in middle aged participants and by 5.1-8.7% in elderly participants. Blood glucose clearance, as assessed by area under the curve, was decreased by 6% in the middle aged participants and 4.2-17% in the elderly population. Systolic blood pressure was unchanged in the middle aged participants but was reduced by 5.4-8% in the elderly participants. Following 10 weeks of HIT, circulating lipid profile was significantly improved in the elderly by 11-25.9%. These improvements are speculated to be a result of HIT-induced adaptations in skeletal muscle mitochondrial, cardiac, vascular and metabolic function. Very short duration sprints provide rapid improvements in various aspects of health and could be utilised to promote optimal ageing.