Objective The primary objective of this study was two-fold. First, to determine whether incidental physical activity (IPA), which is composed of both light-intensity physical activity (LPA) and sporadic moderate-intensity physical activity (MPA; physical activity accrued in bouts less than 10 minutes), was associated with cardiorespiratory fitness (CRF). Second, to determine whether sporadic MPA was associated with CRF. Methods Participants were abdominally obese (defined as a waist circumference > 102 cm in men and > 88 cm in women), inactive, adult men (N = 24; [mean ± SD] age = 55.5 ± 7.8 years) and women (N = 55; age = 52.3 ± 7.5 years) recruited from Kingston, Canada. Cardiorespiratory fitness was assessed using a graded treadmill test. IPA (activity ≥ 1 metabolic equivalent (MET)) and sporadic MPA (activity ≥ 3 METs accrued in bouts less than 10 minutes) was measured using the SenseWear Pro Armband (SWA). IPA and sporadic MPA were categorized into duration (minutes/day) and expenditure (MET-minutes/day). In secondary analyses, we investigated the association between LPA (activity between 1 – 2.99 METs), sedentary behaviour (SED; activity < 1.0 MET) and CRF. Results Participants accumulated an average of 326.6 ± 127 minutes of IPA per day which was composed of 40.7 ± 17.8 minutes of sporadic MPA and 285.9 ± 118.2 minutes of LPA. Both duration and expenditure of IPA were significantly associated with CRF independent of sex, however, after further control for body mass index and age neither association remained significant (p > 0.05). Sporadic MPA was significantly associated with CRF after control for covariates (p ≤ 0.05). Neither LPA nor SED were associated with CRF after control for covariates (p > 0.05). Conclusions IPA was not significantly associated with CRF, however, sporadic MPA was an independent predictor of CRF. / Thesis (Master, Kinesiology & Health Studies) -- Queen's University, 2011-07-30 16:43:47.703

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The increasing incidence of Alzheimer’s disease (AD) combined with recent evidence suggesting that its neuropathologies begin years prior to symptomatic onset has produced an immense focus on ways to attenuate the related structural and cognitive decline of certain brain regions. One low cost intervention is aerobic exercise. Rodent models have demonstrated aerobic exercise induces adult hippocampal neurogenesis, the birth of new neurons, in the dentate gyrus (DG) subregion of the hippocampus (HC) as well as increased performance on a spatial memory task. Further, human studies have demonstrated the association between increased cardiorespiratory fitness (CRF) and increased HC volume, and its translation to increased episodic memory performance. The goal of this study was to assess the relationship between CRF, as measured by VO2max, and brain region of interest (ROI) volumes notably including the left HC, left DG/Cornu Ammonis 3 (CA), and right entorhinal cortex (ErC). A secondary goal was to assess the relationship between CRF and cognitive performance on the Rey Auditory Verbal Learning Test. Baseline data was collected from 31 healthy older adults as a part of two larger clinical trials on aerobic exercise and HC function. Data included a CRF assessment as measured by VO2max, and structural MRI data including a high-resolution whole-brain T1-weighted image, and a T2-weighted image with higher-in-plane resolution. Automatic Segmentation of Hippocampal Subfields (ASHS) was the neuroimaging software utilized to segment the HC and medial temporal lobe cortices into its appropriate subfields. Multiple linear regressions ran in IBM SPSS 25 to determine if CRF predicted ROI volumes yielded no significant results when controlling for age, sex, intracranial volume, education, and scanner location. Multiple one-way between-subject ANOVAs conducted to compare ROI volumes in high-fit versus low-fit individuals revealed marginal significance for the left HC, but no other ROI. Multiple one-way between-subject ANOVAs conducted to compare cognitive performance in high-fit versus low-fit individuals also revealed no significant results. Considering the marginal significance achieved by the one-way between-subjects ANOVA for CRF and left HC, a larger sample size is needed to potentially achieve significant statistical significance. Given these remaining null results, further investigation is suggested using additional neuroimaging analyses that split the DG/CA3 into its anterior and posterior sections, as well as examining different aspects of the RAVLT or utilizing more sensitive episodic memory tests.

The aim of this research project was to conduct a manual development study and an open clinical trial in order to demonstrate the feasibility and efficacy of a mindfulness and acceptance based intervention for increasing cardiorespiratory fitness (CRF) in sedentary adults through adherence to a fitness walking program. Development of the treatment manual followed a 3-phase process (literature review and initial draft preparation, expert review, draft revision) based on expert systems analysis, and organizational structure was derived from Carroll and Nuro's Stage Model for Psychotherapy Manual Development. Field experts (N=3) were provided with the manual draft, as well as a semi-structured interview form for revision data. The manual included treatment introduction sections for the therapist and the participant, as well as 8 topic modules. In the10-week open trial, sedentary adults (N=24) engaged in a fitness walking program, while attending regular group therapy sessions whose content was based primarily on Acceptance and Commitment Therapy (ACT). Results indicated a large significant decrease in total walk test time [t(18) = 4.61, p = .0002, d = 0.64], with a mean decrease of 64.69 seconds. A moderate significant increase in estimated V0₂max [t(18) = -4.05, p = .0007, d = -0.43] was also evidenced, with a mean increase of 2.9 ml/kg/min. Analyses indicate a moderate non-significant increase in general experiential acceptance as measured by the AAQ-II [t(18) = 1.18, p = .26, d = 0.37], and a large significant increase in experiential acceptance of exercise-related internal experiences [t(18) = -9.19, p < .0001, d = -2.09] as measured by the PA-AAQ. Finally, feasibility and acceptability of the intervention were demonstrated through high levels of adherence to the walking program, group attendance, and measures of comprehension. This study demonstrated the usefulness of ACT in the field of behavioral medicine, particularly with health behavior change. / Ph. D.

Aging is associated with adverse structural and functional changes in the brain. These changes have been directly linked to declines in certain types of learning and memory, likely due to the negative impact of aging on the hippocampus, a region necessary for cognitive functions such as relational learning, memory, and spatial navigation. Health behaviors and characteristics, like exercise and cardiorespiratory fitness (CRF), are related to better brain and cognitive aging, though more research is needed to better understand which age-sensitive aspects of cognitive function are most benefited by these health characteristics. The purpose of this collection of studies was to examine how exercise and fitness affect older adults’ learning and memory abilities, specifically using tasks that are designed to tax hippocampal binding processes. Further, I aimed to determine whether the volume of the hippocampus plays a key mediating role in this relationship. I answer these questions with three specific aims, each testing part of a model that represents complex interactions between physical activity, fitness, learning, and the potential mediator of hippocampal volume. The first aim examines these relationships using a cross-sectional design of 45 cognitively healthy older adults. The second aim evaluates the effects of a 12-week moderate intensity exercise program on 37 previously low-active older adults’ fitness, hippocampal volume, and relational learning rate. In this aim I first examine the amount of change in multiple variables following the intervention in order to infer causal relations, and then I examine the relationships of change across the different outcome measures. Finally, the third aim evaluates in 40 healthy older adults the role of hippocampal structure in the relationships between fitness and both spatial learning and memory in a virtual navigation task that has been found to be sensitive to age and disease-related changes in the hippocampus. In the first aim I found that higher cardiorespiratory fitness (CRF) was associated with larger hippocampal volume and faster relational learning rate. Larger hippocampal volume was also associated with faster learning rate. This pattern of results supports my hypotheses and provides a novel finding about how CRF relates specifically to older adults’ relational learning, which is thought to place demands on hippocampal binding. In the second aim I found that 12-weeks of regular light and moderate exercise increased CRF and early learning of relational associations. These changes were not larger for moderate intensity stationary cycling compared to light intensity stationary cycling. I also unexpectedly found that hippocampal volume decreased for both exercise groups, which suggests that this exercise intervention did not mitigate potential age-related decline in hippocampal volume. Finally, in the third aim I found that CRF was not related to learning object locations on spatial navigation, but higher CRF was related to fewer memory errors on the delayed recall of object locations in the virtual environment. Additionally, hippocampal volume was positively associated with the number of object locations learned after the first five minutes of free exploration in the virtual environment. Overall I found that higher CRF is related to faster relational learning and better memory of spatial object locations, both of which are expected to tax hippocampal binding processes. As even healthy older adults tend to experience structural and functional decline in the brain, CRF may be an effective health characteristic to target to increase the active life expectancy of our aging population.

Aging is associated with cognitive decline in various domains, including memory. The age-related increase in systemic inflammation has been identified as a potential mechanism contributing to these memory impairments. Specifically, elevated inflammation may impair neurotrophic factor production and function, which is important for maintaining brain health. Physical activity has been identified as a potential strategy for preventing or delaying memory decline, given its ability to reduce inflammation and stimulate neurotrophic factor expression. The present study investigated the relationship between cardiorespiratory fitness, a proxy for habitual physical activity, and memory in older adults. Inflammation and neurotrophic factors were examined as potential mechanisms mediating this relationship. Sixty-five community dwelling older adults (Mage = 70.6 ± 4.0) completed the Rockport 1-mile walk test to predict their cardiorespiratory fitness, as well as the Mnemonic Similarity Task to assess memory. Serum samples were collected to examine inflammatory markers, including interleukin-6 (IL-6), interleukin-1beta (IL-1β), tumor necrosis factor-alpha (TNF-α), and C-reactive protein (CRP), as well as neurotrophic factors, including brain derived neurotrophic factor (BDNF) and insulin-like growth factor-1 (IGF-1). No relationship was found between cardiorespiratory fitness and memory (p > .05). However, older adults with greater cardiorespiratory fitness had lower levels of IL-6 (p < .01) and TNF-α (p < .01) and trended towards higher levels of BDNF (p = .078). Furthermore, IL-6 was negatively correlated with IGF-1 (p < .01), suggesting higher inflammation may impair IGF-1 production. Contrary to our hypotheses, sequential mediation analyses revealed no indirect effect of inflammatory markers and neurotrophic factors on the relationship between cardiorespiratory fitness and memory. Our results suggest that cardiorespiratory fitness may promote favourable changes in inflammatory markers and neurotrophic factors, which—given previous literature—could help to support brain health with advancing age. More research is needed to further examine the relationship between cardiorespiratory fitness and memory. / Thesis / Master of Science (MSc)

The medial temporal hippocampal system exhibits high plasticity and is influenced by behavioral and socioenvironmental factors. Animal models have demonstrated the neuroplasticity of this system through environmental enrichment, exercise, and chronic stress. Human studies have replicated these findings, highlighting the positive impact of exercise and cardiorespiratory fitness, as well as the detrimental effect of chronic stress on brain structure. However, limited research has explored the differences between young and older adults in extrahippocampal regions of the medial temporal lobes. Additionally, the impact of psychosocial stressors such as perceived discrimination and moderating factors like sense of control on this brain system remains understudied. Furthermore, there is a lack of investigation into the neurobiological consequences of perceived discrimination as a significant psychosocial stressor on neurocognitive health. The goals of this dissertation project were to investigate the role of cardiorespiratory fitness and perceived discrimination on medial temporal hippocampal system neurocognitive integrity in humans. I had two hypotheses. First, higher cardiorespiratory fitness would correlate with higher extrahippocampal cortical thickness in young and older adults. Second, a greater number of experiences of perceived discrimination would correlate with reduced amygdala and anterior hippocampus volume in older adults. Two experiments were conducted to assess the impact of behavioral and socioenvironmental factors on medial temporal hippocampal system structure. In the first experiment, cross-sectional data were collected from two randomized clinical controlled trials (n = 100; 56 young adults and 44 older adults). In the second experiment data were collected from two pilot studies (n = 36). Finally, we discuss how the built and social environment, artificially created or modified areas where individuals live, work, or engage in recreational activities, can facilitate or impede behaviors that benefit brain health such as physical activity to increase cardiorespiratory fitness or social engagement. Experiment 1 used structural MRI and assessed cardiorespiratory fitness in sedentary young and older adults. The primary objective was to examine the relationship between cardiorespiratory fitness and entorhinal, parahippocampal, and perirhinal cortical thickness. The results indicated a positive association between cardiorespiratory fitness and cortical thickness in these regions, specifically in the left hemisphere of young adults. However, this relationship was not observed in older adults. Experiment 2 focused on the association between participants' perceived social discrimination experiences and amygdala and anterior hippocampus volume. Additionally, the moderating role of locus of control, a measure of self-efficacy, was examined. The findings revealed that higher levels of perceived social discrimination were associated with reduced amygdala and anterior hippocampus volume. Moreover, higher levels of locus of control attenuated the relationship between perceived social discrimination and these brain regions. The third project integrated the aforementioned ideas within the context of the built and social environment. The discussion centered around how systemic barriers within the environment can either support or hinder engagement in health-promoting behaviors like cardiorespiratory fitness. The importance of considering the built and social environment in clinical interventions was highlighted, with a focus on improving translation of research findings to benefit research participants. Factors such as safety, access to green spaces, and social connectedness were explored, particularly in relation to universal design and its potential to enhance healthy aging and accessibility while addressing systemic racism and structural barriers. These chapters provide evidence to inform policymakers, clinicians, and neuroscientists about the broader implications of clinical research in communities. By considering the impact of clinical interventions on the built and social environment, this work aims to promote health and well-being beyond laboratory settings.

Over the past several decades abdominal obesity and physical inactivity have increased at an alarming pace. Since both are related to adverse health risk it is important to determine their independent influence. It is well established that cardiorespiratory fitness (CRF, the ability to perform physical activity) and physical activity (PA) are negatively associated with cardiometabolic risk factors (commonly obtained risk factors for disease, e.g: TG, HDL, etc.). In other words, the higher a person’s levels of PA and fitness, the lower that person’s likelihood of developing cardiometabolic risk factors. Abdominal obesity is positively associated with cardiometabolic risk factors which means the more abdominally obese a person is, the more prone that person is to develop cardiometabolic risk factors. However, it is unknown whether PA influences cardiometabolic risk factors independent of fitness level and/or abdominal obesity. My study objective was to examine whether PA is associated with cardiometabolic risk factors independent of cardiorespiratory fitness and/or abdominal obesity in inactive abdominally obese women. The study enrolled 141 inactive abdominally obese women. PA, cardiorespiratory fitness, and cardiometabolic risk profile were measured in all participants. A novel feature of this study was the use of the accelerometer to objectively measure PA and to divide exercise into different levels of intensity, such as: low PA, moderate to vigorous PA (MVPA), etc. My findings revealed that abdominal obesity was positively associated with cardiometabolic risk independent of PA or CRF. I also observed that CRF was inversely related to cardiometabolic risk independent of PA or abdominal obesity. MVPA explained cardiometabolic risk factors by itself, but with insulin resistance measurements (2-hour glucose, and homeostasis model of assessment) this relationship was abolished when abdominal obesity and CRF were also taken into consideration. The findings of this study provide further support for the recommendation that waist circumference and CRF be included as routine measures screening for cardiometabolic risk factors in inactive obese women. Our findings also support the suggestion that even modest amounts of daily MVPA that are below the recommended threshold of 30 minutes/day convey health benefit. / Thesis (Master, Kinesiology & Health Studies) -- Queen's University, 2013-07-23 13:46:57.088

Aging is associated with increased insulin resistance, a condition in which the tissue response to insulin-stimulated glucose uptake is reduced. Insulin resistance is a strong predictor of disease and mortality. Aging is also associated with a decline in physical activity, lower cardiorespiratory fitness (ability to deliver oxygen to active muscles during exercise), and increase in abdominal fat. Both low cardiorespiratory fitness (CRF) and excess abdominal fat are associated with reduced insulin sensitivity in older adults. Improvements in CRF and abdominal obesity through exercise training may be responsible for improvement in insulin sensitivity. Several investigations have reported that changes in CRF and abdominal obesity through exercise are associated with changes in insulin sensitivity. To our knowledge, no prior study has assessed whether change in CRF or abdominal fat alone explains the association between exercise and improvement in insulin sensitivity in older adults. Our findings suggest that improvement in CRF may not explain the exercise-induced change in insulin sensitivity. The improvement in insulin sensitivity from exercise is explained through a decrease abdominal fat that also occurs with exercise. Additionally, improvements in waist circumference, a surrogate measure for abdominal obesity, and body mass index together explained a large portion of exercise-induced change in insulin sensitivity compared to either variable alone. Our findings suggest that exercise combined with a healthy diet will improve insulin resistance, a risk factor for development of type 2 diabetes and cardiovascular disease in older adults. Our findings suggest that the reduction in abdominal obesity is the conduit by which exercise improves insulin sensitivity in older adults. Although CRF is not related to exercise-induced change in insulin sensitivity, change in CRF from exercise has been reported to decrease risk for other health conditions, such as hypertension and all-cause mortality. Our findings suggest that clinicians should measure both waist circumference and body mass index when evaluating the effectiveness of a lifestyle-based treatment strategy for improving insulin resistance and its associated health outcomes in older adults. / Thesis (Master, Kinesiology & Health Studies) -- Queen's University, 2013-09-27 14:53:00.796

Made available in DSpace on 2014-06-11T19:30:52Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-08-27Bitstream added on 2014-06-13T20:21:21Z : No. of bitstreams: 1 barros_seb_dr_rcla.pdf: 887445 bytes, checksum: 944f1e2052c0ea22941e6cca91732214 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O envelhecimento promove mudanças nos diversos sistemas, especialmente músculo-esquelético e cardiopulmonar. Exercícios físicos regulares melhoram o condicionamento cardiorrespiratório, modificam as dimensões corporais e neuromusculares, amenizando o impacto do envelhecimento na capacidade funcional. Com o objetivo de analisar os efeitos do exercício físico sobre indicadores pulmonares e antropométricos em idosas, dois estudos foram realizados. O Estudo 1 observou os efeitos da especificidade do exercício sobre indicadores antropométricos e pulmonares em idosas. Quarenta mulheres acima de 60 anos, compuseram quatro grupos (Sedentárias, Hidroginástica, Musculação e Dança). O Estudo 2 verificou os efeitos de um Programa de Exercícios Generalizados (PEG) em indicadores antropométricos e pulmonares em mulheres sedentárias entre 60 a 78 anos. Participaram do estudo trinta e duas mulheres, que compuseram dois grupos: Controle (n=14) e Intervenção (n=18). Para ambos os estudos, foram analisadas as variáveis antropométricas (índice de massa corpórea, circunferência muscular do braço e panturrilha, dobra cutânea tricipital e relação cintura/quadril); nível de atividade física (Questionário de Baecke) e função pulmonar [pressões respiratórias máximas, mobilidade torácica e espirometria (capacidade vital forçada - CVF, volume expiratório forçado no primeiro segundo - VEF1, relação VEF1/CVF, fluxo médio expiratório forçado - FEF25-75% e pico de fluxo expiratório)]. No Estudo 2, as participantes foram reavaliadas após 4 meses de intervenção. No Estudo 1, para o nível de atividade física, houve diferenças quanto à especificidade do exercício (p ≤ 0,001) entre Sedentárias e demais... / Aging promotes changes in many systems, especially for musculoskeletal and cardiopulmonary functions. Regular physical exercise improves cardiorespiratory fitness and modifies body and neuromuscular dimensions, all while softening the impact of aging on functional capacity. To analyze the effects of physical exercise on pulmonary and anthropometric measurements in older women, two studies were conducted. Study 1 observed the effects of specific exercises on anthropometric and lung measurements in elderly women. Forty women over 60 years old in four groups (Sedentary, Hidroginastics, Bodybuilding and Dance) were studied. Study 2 examined the effects of a generalized exercise program (GEP) on anthropometric and lung measurements in sedentary women between 60-78 years. Thirty-two women, formed two groups: Control (n = 14) and Intervention (n = 18). For both studies, we analyzed anthropometric variables (body mass index, arm and calf muscle circumference, triceps skinfold thickness, and waist/hip ratio), level of physical activity (Baecke questionaire), pulmonary function [maximal respiratory pressures, thoracic mobility and spirometry (forced vital capacity - FVC, forced expiratory volume in one second - FEV1, FEV1/FVC, forced expiratory flow medium - FEF25-75% and peak expiratory flow)]. Participants were reassessed after four months of intervention. Study 1 participants were assessed according to level of physical activity, there were differences in the specificity of exercise (p ≤ 0,001) between sedentary and other groups as well as between hidroginastics and the two groups (dance and bodybuilding). In axillary thoracic mobility, there were differences between bodybuilding and the sedentary and dance groups (p ≤ 0,05). Differences also occurred for xiphoid thoracic... (complete abstract click electronic access below)