Considering the increasing global prevalence of overweight and obesity and their propensity for disease, this study was undertaken in an attempt to optimize exercise prescription for this at-risk group by determining if the benefits associated with interval training occur in an intensity dependent manner. 19 sedentary, overweight males (Age: 22.7 ± 3.9 yrs, BMI: 31.4 ± 2.6 kg/m2, WC: 106.5 ± 6.6 cm) performed interval training for three weeks at either 70% or 100% of their peak work rate on a cycle ergometer. Aerobic capacity measurements, time to completion trials, muscle biopsies, and fasted blood samples were all performed pre and post training. Analyses of aerobic capacity and exercise performance demonstrate greater improvements made in the 100% compared to the 70% group, while measures of skeletal muscle oxidative capacity indicate equivalent changes between groups. Taking into account the similar increases in mitochondrial content in both groups and understanding the influence of both oxygen supply and demand in determining maximal oxygen consumption, the greater increases in aerobic capacity achieved by the 100% group may be the result of enhanced cardiovascular adaptations. These findings suggest that some of the health benefits associated with interval exercise may be intensity dependent. Therefore, there may be additional benefit to exercise at higher intensities. / Thesis (Master, Kinesiology & Health Studies) -- Queen's University, 2012-09-27 17:26:19.425

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.

Recent research suggests that [beta]-hydroxy-[beta]-methylbutyrate (HMB), a metabolite of leucine (Leu), increases muscle mass and attenuates muscle damage during resistance training. Although Leu acts as a potent stimulator of protein synthesis, HMB, but not Leu, has been reported to be effective in suppressing proteolysis in skeletal muscle. However, mechanisms for the effects of HMB on cell signaling pathways controlling muscle protein turnover during rest and after endurance exercise are still poorly understood. Furthermore, the effects of HMB on cell signaling pathways controlling protein synthesis and degradation under normal in vivo conditions warrant further investigation. For optimal gains in muscle mass, the appropriate type and amount of protein (PRO) is required for positive protein balance to occur in skeletal muscle. Therefore, this dissertation was designed to determine the effect of HMB, PRO and Leu, individually and in combination, on the regulation of cellular signaling pathways controlling muscle protein turnover during sedentary and post-exercise conditions. Study 1 demonstrated that, compared with HMB and PRO alone, the combination of HMB and PRO was more effective in activating the mTOR signaling pathway, which controls protein synthesis, and inhibiting FOXO3A, a major regulator of the ubiquitin-proteasome proteolytic signaling pathway. Study 2 demonstrated that, compared with its individual components, a novel HMB/PRO/Leu supplement better activated protein-synthetic signals and inhibited proteolytic signals in skeletal muscle, and these effects were better sustained. Finally, Study 3 demonstrated that adding Leu to PRO-enriched mixtures after exercise additively activated protein-synthetic signals in a fiber type-specific manner, and adding HMB clearly inhibited proteolytic signaling proteins. Furthermore, provision of an HMB/PRO/Leu supplement after exercise was found to favorably modulate signaling pathways controlling both protein synthesis and degradation. Taken together, the results of these studies suggest that a novel nutrient supplement, composed of HMB, Leu and PRO, additively enhances the intracellular signaling proteins controlling protein synthesis and attenuates signaling proteins controlling proteolysis in skeletal muscle during sedentary and post-exercise recovery. Therefore, such a supplement may be beneficial for both athletic and therapeutic purposes. / text

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Yes / Purpose: Raised postprandial triglycerides (TAG) and related oxidative stresses are strongly associated with increased cardiovascular disease (CVD) risk. Acute exercise and strawberry ingestion independently ameliorate postprandial lipid excursions and oxidative stress. However, the combined effects of these lifestyle interventions is unknown. We investigated whether acute exercise and strawberry consumption improved postprandial responses to an oral fat tolerance test (OFTT) in overweight/obese males. Methods: Overweight/obese adult males underwent four separate OFTT (73g fat, 33g carbohydrate) with blood sampled at baseline and hourly for 4 h after OFTT. Two OFTT contained 25g freeze-dried strawberries and two contained strawberry flavouring (placebo). Participants performed 40 minutes of submaximal high intensity interval cycling exercise (HIIE) 16 h before one strawberry and one placebo OFTT, and rested before the remaining two OFTT. Serum TAG was analysed and TAG area under curve (AUC) and incremental AUC (iAUC) were calculated. Oxidative stress markers were measured at baseline and 4 h. Differences between conditions (strawberry/placebo and exercise/rest) were assessed using repeated measures ANOVA. Results: Ten males (Age, 31.5 IQR 17.8 years; BMI, 29.9 ±1.8 kg.m-2) completed the study. TAG AUC was 1.5 mmol.4h-1.L-1 lower for the exercise conditions compared to the rest conditions (95% confidence interval [CI]= -2.3 to 0.8, p= 0.001). TAG AUC was not different between the strawberry and placebo conditions (CI= -1.3 to 0.6, p= 0.475). TAG iAUC was 0.5 mmol.4h-1.L-1 greater for the strawberry compared to the placebo conditions (CI= 0.1 to 1.0, p= 0.021). There were no changes in markers of lipid related oxidative stress (P> 0.05). Conclusion: Acute submaximal HIIE appears effective in reducing postprandial lipaemia in overweight/obese adult males. However, strawberry ingestion did not improve postprandial TAG.

The purpose of this study was to compare the exercise and recovery muscle oxygenation response of Women and Girls during two 30s Wingate anaerobic tests separated by two minutes of active cycling recovery (resistance ≈ 2.5% body weight, 60-80rpm). Oxygenated hemoglobin (HbO2), deoxygenated hemoglobin (HHb), total hemoglobin (tHb), and tissue saturation index (TSI) were monitored at the right vastus lateralis muscle using near infrared spectroscopy (NIRS) throughout exercise, recovery, and a post-exercise femoral artery occlusion to TSI plateau. Pressure was preset at 250mmHg for Women and 210mmHg for Girls, achieved by rapid inflation in 0.3 seconds, and maintained until a 2 minute TSI plateau occurred or 10 minutes had passed. Twenty Women (23.8[2.12] years) and 13 Girls (9[1] years, combined Tanner stage <4) completed all tasks excepting 1 girl who did not complete occlusion. Significant group, time, and group by time interaction effects were observed for peak and mean power (Watts.kgFFM-1). Women had significantly greater power output compared to Girls for both Wingates. While both groups had reduced power output in Wingate 2, the reduction was significantly greater in Women compared to Girls. No significant group differences were found for resting TSI, recovery TSI, minimum TSI during either Wingate test, or for minimum TSI during occlusion, however a time main effect for Women was observed with minimum TSI being significantly lower in Wingate 1 compared to Wingate 2. Girls had similar minimum TSI for both Wingate tests. Women also demonstrated a significantly greater difference between Wingate minimum TSI and occlusion minimum TSI in Wingate 2 compared to Wingate 1. During Wingate 1, HHb increase was greater in Girls compared to Women and remained elevated during recovery compared to women. Changes in HbO2, HHb, and tHb were reduced in Wingate 2 for both groups, more so in Women for tHb and in Girls for HHb. Recovery was not different between groups with the exception of a faster TSI time constant of recovery in Women (τ =20.25 [13.01]s) compared to Girls (τ =36.77 [13.38]s) which is attributed to a faster HHb time constant in Women (τ =13.6 [0.44]s) compared to Girls (τ =30.77[19.47]s). Both groups demonstrated similar power output results and TSI response across the two Wingate tests but Girls were better able to repeat the anaerobic performance with a consistent TSI minimum between the two tests despite a faster recovery of HHb and TSI in women. These findings, in the context of observed Hb variable differences between groups, provide evidence of greater oxidative metabolism in Girls during a high intensity exercise. / Graduate / December 18, 2016

Ischaemia reperfusion injury (IR-injury) occurs when blood supply to a certain area of the body is blocked, and is subsequently followed by reperfusion. During the period of ischaemia, tissue is damaged as a result of lack of oxygen. Rapid reperfusion is mandatory, but unfortunately causes damage in addition to the damage induced by ischaemia alone. While a prolonged period of ischaemia is harmful to the bodily tissue, short periods of ischaemia interspersed with short bouts of reperfusion have protective effects. This mechanism is called ischaemic preconditioning (IPC). In this thesis, the impact of co-morbidity and age on IR-injury and IPC are explored. Moreover, the possible role of IPC to enhance exercise performance is investigated. Finally an attempt is made to understand the interchangeable effects of IPC and exercise performance in the prevention of IR-injury. Using the brachial artery endothelial function as a surrogate marker, first the consequences of IR-injury in both young and older individuals on endothelial function were studied. It was also assessed whether IPC could prevent endothelial IR-injury. It was found that endothelial function in both groups declined, when IR-injury was not preceded with IPC. However, when IPC was applied prior to IR-injury, a protective effect was detected in young subjects, but not in older participants. In chapter 5, this study was repeated in patients with heart failure, as they are at an increased risk for IR-injury. While in both groups a significant decline in endothelial function was observed, a much larger decline was established in the heart failure group. Moreover, IPC failed to protect against endothelial dysfunction in heart failure patients after IR-injury. The third study presented in this thesis, focused on the question whether exercise performance enhancement during a 5-km time trial was comparable when IPC on the upper legs was applied immediately before the time trial versus 24 hours (24-IPC) prior to exercise. Interestingly, a significant and strong correlation was found in finish time between acute IPC and 24-IPC, suggesting comparable effects of IPC and 24-IPC on exercise performance. In a follow-up study, it was determined whether local IPC applied on the upper arm, or remote IPC applied on the legs, would lead to an improved maximum incremental arm crank exercise test in individuals with a complete spinal cord lesion. The main finding was that upper arm IPC led to an increased performance enhancement, whilst remote IPC (stimulus below the lesion) did not lead to any significant differences. These studies help to inform the best or most practical application of IPC in daily life situations. Some previous work has suggested that exercise may resemble some of the effects of IPC. More specifically, acute exercise might possess the same protective effects against ischaemia-reperfusion injury as IPC. Therefore, in young healthy individuals it was studied, whether an acute bout of endurance or interval exercise is able to protect against brachial endothelial IR-injury. It was established that interval exercise prevented endothelial dysfunction after an IR stimulus, while no protective effect of endurance exercise was found. It was concluded that interval exercise, but not endurance exercise, prevented endothelial dysfunction after an ischaemic period. In conclusion, this thesis provides further evidence for the protective effects of (remote) IPC, both on the prevention of endothelial IR-injury as well as improvement in exercise performance. However, effects may depend on the protocol and population studied.

Orientador: Angelina Zanesco / Banca: Aparecida Maria Catai / Banca: Everardo Magalhães Carneiro / Banca: Silvia Marina Anaruma / Banca: Lilian Teresa Bucken Gobbi / Resumo: A menopausa é um advento na vida da mulher que se caracteriza por alterações antropométricas, metabólicas e hemodinâmicas e que culmina com a predisposição do aparecimento ou agravamento de diversas doenças. O exercício físico aeróbio é considerado uma importante estratégia por promover melhora na função cardiovascular, respiratória e metabólica. Nenhum estudo avaliou a influência do exercício físico intervalado sobre os níveis de NO, receptor de leptina e pressões respiratórias em mulheres na menopausa. Assim, o objetivo deste estudo foi avaliar os efeitos do treinamento físico aeróbio intervalado nos níveis plasmáticos do receptor solúvel de leptina (Rb-e) e nitrito/nitrato sua correlação com a pressão arterial em mulheres no climatério. Participaram deste estudo, 23 mulheres (55±5 anos) treinadas por 12 semanas, frequência de 3 vezes por semana, duração de 30minutos, com intensidade entre 60% a 80% da frequência cardíaca de reserva. Medidas antropométricas (IMC e CA), cardio-respiratórias (teste de capacidade aeróbia e aferições da pressão arterial e respiratória) e bioquímicas dos níveis plasmáticos do receptor de leptina e nitrato/nitrito foram realizadas. Nossos resultados mostram que as mulheres no climatério apresentaram: reduções significativas da circunferência abdominal (3,8%) e redução de 6,7% na pressão arterial diastólica. Observamos também aumento no VO2max.,(25,1+0,8 para 26,5+0,9ml/kg/min) e nas pressões expiratória e inspiratória (11 e 20%, respectivamente). De maneira similar, tanto os níveis plasmáticos do receptor de leptina (basal: 47,2+3,5 TR: 54,1+ 3,6ng/ml) quando de nitrito/nitrato (55%) foram aumentados pelo treinamento físico aeróbio intervalado por 3 meses. Em nosso estudo, podemos concluir que o exercício físico aeróbio intervalado por 3 meses promoveu aumento na concentração plasmática... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Menopause is characterized by a variety of alterations including weight gain and increase in the incidence of cardio-metabolic disorders in women life. Although its is well known that physical exercise plays an important role in preventing and/or reducing the deleterious effect of cardio-metabolic diseases, no studies have been investigated the effect of intermittent aerobic physical exercise on the plasma soluble leptin receptor, nitrite/nitrato levels, lung function in postmenopausal women. Therefore, the aim of this work was to evaluate the effect of intermittent aerobic physical training for three months on the plasma soluble leptin receptor and nitrite/nitrato levels and its relationship with pulmonary function and blood pressure in postmenopausal women. Twenty-three volunteers were enrolled in the training program, 3 days/week, 30 minutes, during 3 months. The range of the training intensity was from 60 to 80 % of reserve heart rate. Anthropometric, cardio-respiratory and biochemical parameters were evaluated at the basal and after 3 months of exercise training. Our findings show that intermittent exercise training promotes a significant decrease in the waist circumference (3.8%) as well as diastolic blood pressure (6.7%). An increase in both VO2 max (basal: 25.1+0.8 Trained: 26.5+0.9 ml/kg/min) and respiratory function (Insp: 11 and exp: 20%). Similarly, both plasma soluble leptin receptor (basal: 47.2+3.5 TR: 54.1+ 3.6 ng/ml) as well as nitrite/nitrato levels were increased after exercise training (55%) in postmenopausal women. Therefore, our findings show that intermittent aerobic training during 3 months promoted beneficial effects on the cardiovascular function that was positively associated with increase in soluble leptin receptor and nitrie/nitrato levels in postmenopausal women. Furthermore, our data suggest that plasma soluble leptin receptor might be a marker for the beneficial effect of interval exercise training / Doutor

abstract: The Western Pattern diet has been characterized by having greater than 50 percent consumption coming from fat and sugar. This macronutrient allocation has been shown to have deleterious effects on endothelial function and metabolic markers of cardiovascular disease. Exercise has been shown to improve vascular reactivity and metabolic markers related to cardiovascular health. The objective of the study was to determine if exercise training can prevent the anticipated deleterious effects of a fat-sugar supplemented diet on endothelial function and blood markers of cardiovascular risk in young men. Twenty-one, healthy college-aged males were randomly assigned to either the doughnut + exercise or doughnut only groups. Both groups were fed 2 doughnuts per day, 6 days per week, for three weeks, while maintain their current diet. The exercise group completed 4 exercise training sessions per week consisting of 2 high intensity interval training bouts (up to 95% VO2peak) on a cycle ergometer and two moderate intensity, steady-state bouts (at 75% VO2peak) on a treadmill. Changes in body weight and composition, markers of endothelial function, oxidative stress, serum lipids, and blood glucose were measured in each group. As expected, cardiovascular fitness increased significantly in the doughnut-supplemented + exercise group as compared to the doughnut-supplemented (p=0.005). Significant increases in body weight (p=0.036), fat mass (p=0.013), and body fat percentage (p=0.014) were seen in the doughnut only group as compared to the doughnut + exercise group. The doughnut + exercise group showed significant improvements in fasting serum triglycerides (p=0.036), plasma insulin (p=0.039) and insulin sensitivity (HOMA; p=0.05) as compared to the doughnut only group. The doughnut + exercise group saw a significant improvement in nitric oxide availability whereas the doughnut only group experienced a significant decline (p=0.014). There were no significant changes in other markers. Despite the addition of a fat/sugar supplement of ~11,600 kcal over three weeks, 4 exercise sessions per week were sufficient to prevent a gain in body weight and fat mass, and also improve some measures of cardiometabolic risk. These results suggest that exercise may be necessary to prevent some adverse health outcomes associated with transient periods of excessive energy consumption. / Dissertation/Thesis / Ph.D. Physical Activity, Nutrition and Wellness 2013

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