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Endurance training results in cardiac and haematological adaptations that underpin improvements in cardiorespiratory fitness. These adaptations are well-established in adults, but the adaptive processes are less clear in children. It was originally hypothesised that pre-pubertal training adaptations are blunted due to a lack of growth-related and sex hormones. Left ventricular (LV) remodelling to training has since been shown pre-puberty, although less pronounced, whereas haematological adaptations remain unclear. Importantly, previous studies investigating training-related cardiovascular adaptations have often not quantified maturity, which is crucial given the large interindividual timing of puberty. Additionally, the majority of previous work has focussed on boys, or pooled mixed sex data, making female characteristics impossible to discern. However, if cardiac and haematological adaptations are more pronounced post-puberty, their contribution to maximal aerobic power (V̇ O2max) is likely to increase, similar to adult observations. Also, greater training-related cardiac remodelling with maturity could also lead to greater functional remodelling due to the intricate link between form and function. Therefore, this thesis aimed to assess the influence of maturation on cardiac and haematological adaptations and investigate their contributions to V̇ O2max. A holistic and comprehensive approach was taken to address this aim with the inclusion of both boys and girls, and multiple elements of the oxygen transport chain assessed in both pre- and postpubertal children. The findings show that training-related differences in the LV and haematology are augmented following maturation. Enhanced LV structures after maturity may be driven by expanded circulating blood volumes. These greater central adaptations after maturity explain a larger proportion of V̇ O2max compared with before, despite similar aerobic fitness at each stage. Lastly, the greater LV structures in trained groups after maturity were related to lower systolic LV twist mechanics. Collectively, these findings help to answer historical speculation around the influence of maturation on cardiovascular adaptations to endurance training.

Type 2 diabetes (T2D) is a complex chronic disease which is associated with micro- and macro-vascular complications and premature mortality. This multifactorial disease originates from a complex interplay between genetic, behavioural and environmental risk factors, the underlying mechanisms of which are unclear. The goal of this thesis was to investigate the contributions of genetic, metabolic and behavioural risk factors in the aetiology of T2D by studying large-scale population studies, in order to provide insights for the development of T2D prevention and intervention strategies. I first conducted a genome-wide association study on T2D in a large prospective cohort study for T2D, the EPIC-InterAct study. This work provides a valuable resource for the research community to conduct in-depth genetic investigations on T2D. The strongest T2D-associated genetic variant was at the established TCF7L2 locus. I then used the profiling of behavioural factors in the EPIC-InterAct study to show that there was no interaction between TCF7L2 genetic variants and an index of the number of health behaviour goals achieved, a measure that was strongly associated with diabetes risk. In a meta-analysis of three randomised controlled trials designed to investigate the effect of lifestyle intervention on the risk of developing T2D, I showed that there was no overall interaction between TCF7L2 and allocation to the intervention rather than the control arm. However, there was an interaction in one trial, which focused more on physical activity and dietary change than on weight change. In an analysis of a detailed quantitative metabolic trait study, I demonstrated a specific interaction between TCF7L2 and physical activity energy expenditure (PAEE). These data suggest that genetic targeting could have additive effects with health behaviour interventions and may be more valuable for personalised prevention if linked to very specific behaviours. To build on this observation and explore the potential mechanisms through which physical activity may affect the risk of T2D in different genetic subgroups, I undertook a systematic investigation of interaction effects between PAEE and genetic risk scores for glycaemic traits in the Fenland study. I did not find any significant interaction. Alternatively, using an agnostic approach, I searched for potential interactions with PAEE across the genome. Preliminary analyses detected three variants showing genome-wide significant interaction effects, although the mechanisms were unclear. As obesity is a strong risk factor for T2D and a previous study had reported that BMI modifies the effect of LAMA1 gene on T2D risk, I undertook an in-depth analysis of this potential interaction in the large-scale UKBB and EPIC-InterAct studies. I showed and confirmed that LAMA1 has a stronger effect on T2D among lean individuals compared with obese individuals in independent studies. Observational studies suggest that low cardiovascular fitness (CRF) is an independent T2D risk factor. However, it is unclear whether the association is causal or is due to confounding. I performed the largest genetic discovery of cardiorespiratory fitness in the UKBB study and developed a genetic risk score for CRF. In Mendelian randomisation analyses, I showed that the associations of this score with T2D and hyperinsulinaemia were compatible with underlying causal relationships. High-throughput metabolomics based on large-scale population studies offers a great opportunity for providing direct biological insights and identifying physiological alterations linking risk factors to T2D. I characterised the metabolic profiles of physical activity and cardiorespiratory fitness and identified shared and distinct signatures highlighting the roles of branched-chain amino acid metabolism and fatty acid oxidation. Overall, my PhD work contributes towards 1) a wider understanding of interpersonal differences for diabetes risk in response to behavioural factors based on variable genetic make-up and its implication in population-level diabetes prevention and intervention strategies 2) the discovery of the genetic basis of cardiorespiratory fitness and the provision of strong evidence supporting its causal role for T2D; 3) the characterisation of metabolic profiles of physical activity and cardiorespiratory fitness and the generation of hypotheses for potential biological pathways and physiological mechanisms underlying their influences on diabetes development.

South Asians have a higher risk of cardiovascular disease (CVD) and type 2 diabetes (T2D) than white Europeans. The mechanisms responsible remain partially understood with physical activity and cardiorespiratory fitness possibly playing a role. Thus, this thesis examined ethnic differences in traditional and unconventional CVD and T2D risk markers including appetite-related hormones and inflammatory markers as well as free fatty acids based on metabolomics methods, between South Asian and white European men. Furthermore, this thesis explored associations with objectively-measured physical activity/cardiorespiratory fitness and examined effects of acute exercise on subjective appetite ratings, appetite-related hormones and ad libitum energy intake. In study 1 (Chapter 3), South Asians exhibited lower fasting acylated ghrelin, high-density lipoprotein and V̇O2max than white Europeans but higher body fat percentage, C-reactive protein, leptin, triacylglycerol, glucose and insulin concentrations. Study 2 (Chapter 4), revealed higher laurate, myristate, palmitate, γ-linolenate and linoleate concentrations in South Asians than white Europeans. Free fatty acids were strongly correlated with body fat percentage and total area under the curve for glucose in South Asians and with total step counts in white Europeans. Study 3 (Chapter 5) revealed similar appetite perceptions, energy intake and appetite-related hormones between ethnic groups in response to exercise although subtle differences were identified with South Asians exhibiting lower appetite perceptions 2 h after the buffet meal, delta acylated ghrelin concentrations at 4 h and lower carbohydrate intake after the exercise. Acute exercise increased concentrations of delta acylated ghrelin and total peptide YY and induced a transient suppression in appetite perceptions at 4.5 h and stimulation at 6.5 h, without provoking energy compensation in both groups. These data demonstrate that South Asian have an adverse cardiometabolic risk profile than white European men which may be linked to their lower physical activity and cardiorespiratory fitness. Furthermore, these show that South Asians exhibit different levels of acylated ghrelin and FFAs metabolic profile than white Europeans and provide evidence that acute exercise induces a short-term energy deficit irrespective of ethnicity.

The principle aims of this work were two fold; firstly to identify the current dietary intakes (specifically dietary glycaemic carbohydrate (CHO)) and physical activity (PA) and cardiorespiratory fitness (CRF) levels of a UK, postpubertal, adolescent population (n = 105) and assess the relationship between these factors, adiposity and cardiometabolic health. Diet and health relationships were assessed whilst accounting for energy misreporting and controlling for levels of PA and CRF. The effect of excluding dietary misreporters on the associations between glycaemic CHO and health was assessed whilst comparing an established technique (the Goldberg equation) to a novel approach (the ratio of energy intake (EI) to energy expenditure (EE)), which utilised RT3 accelerometry data (EI:EE(RT3)). Associations of PA and metabolic risk factors were also assessed whilst comparing two child specific PA thresholds for the assessment of PA subcomponents. Secondly, the impact of a flexible, ad libitum, low GI dietary intervention on cardiometabolic health was examined in an „at risk‟, overweight, postpubertal, adolescent population. Glycaemic index (GI) but not glycaemic load (GL) was shown to be associated significantly with anthropometric measures (body mass index (BMI), waist circumference (WC)) and adiposity (body fat percentage (BF%)) in this general group of post-pubertal adolescents from Bedfordshire. When adjusting for dietary intake, CRF was also associated with adiposity but PA was not. The prevalence of misreporting varied depending on the method used to assess the validity of dietary intakes; between 23% and 31% increasing to 62.1% (in overweight) of adolescents under reported energy intakes and up to 11.1% over reported. The novel application of a triaxial accelerometer to measure EE resulted in more under and over reporters being identified than when compared to the widely used Goldberg equation. Increased dietary GI was associated with increased odds of having a high WC; however, associations between GL and other risk factors were less clear; no associations with risk were observed. Excluding dietary misreporters from analysis had important implications for these associations. Only after removal of misreporters by EI:EE(RT3) was a borderline significant positive association between GL and blood glucose (BG) revealed using multiple analysis of covariance (MANCOVA), that was not present in prior analyses. Increased GI (moderate vs low GI intake) was significantly associated with reduced high density lipoprotein cholesterol (HDL) and increased triglyceride (TG) levels (borderline significant) after removal of misreporters. In addition, using different PA thresholds to assess PA intensity resulted in different relationships between PA subcomponents and metabolic risk factors. Regardless of the threshold used, evidence suggested that limiting sedentary (SED) behaviour and engaging in moderate to vigorous PA (MVPA) is beneficial for blood pressure (BP) in this adolescent population. Additionally, irrespective of the threshold utilised, higher levels of vigorous PA (VPA) were associated with reduced odds of having a high clustered risk score and the associations observed between CRF and risk factors were stronger than those observed with PA. Despite a lack of significant improvement in individual metabolic risk factors as a result of the low GI (LGI) dietary intervention, there was a significant reduction in clustered risk score for the LGI group at week 12. A borderline significant improvement in glycated haemoglobin (HbA1c) was also observed as a result of the LGI intervention compared to those in the control group. Conversely, there appeared to be an unfavourable effect of the LGI diet on fasting insulin levels and thus the diet‟s impact on health overall is unclear. The small sample size of this randomised controlled trial (RCT) means that caution is required when interpreting the results. These data suggest that future research in this age group should target improvements in CRF and a lower dietary GI to reduce adiposity. Controlling for dietary misreporting appears to have a significant impact on associations of glycaemic CHO and cardiometabolic health and should be an important consideration of future research. The low GI intervention may be an effective approach for reducing glycaemic CHO, whilst maintaining a healthy macronutrient intake, in comparison to more restricted dietary regimens published in the literature. However, the impact of this regime needs to be confirmed utilising a larger sample of adolescents. This may provide a useful approach for future research aiming to assess the impact of reduced GI and GL.

Objectives: The main question in this study was “Do nutrients present within the MyPlate and Paleo dietary patterns affect exercise parameters in a positive way?” An auxiliary question was “Do nutrients present within these two diets reduce comorbidities of chronic diseases?” Methods: This study analyzed secondary data collected from a previous diet and exercise study. Dietary records were analyzed for correlations between nutrient intake and exercise performance in both diet groups. Further stratification by VO2 peak performance was done to analyze nutrient intake differences between high and low-performing individuals. Results: The MyPlate eating pattern increased body fat percentage, blood pressure, and resting heart rate, while the Paleo eating pattern decreased these variables. The Paleo group consumed fewer carbohydrates, fats, and protein, and more B vitamins, amino acids, omega-3 fats, and other water- and fat-soluble vitamins. Calcium, zinc, iron, and thiamine were positively correlated with an increase in diastolic blood pressure. Peak minute ventilation and relative VO2 peak at baseline were statistically significant in the Paleo group, while the MyPlate group had a lowered peak respiratory exchange ratio. Conclusion: Decreasing total fat mass and increasing total lean mass through a dietary pattern that focuses on the intake of vegetables, fruits, lean meats, eggs, wild game, seafood, and nuts and seeds with a limited intake of refined foods and added sugars is beneficial for exercise performance and overall health outcomes for sedentary weight stable females aged 19-28 not currently following a structured diet in Clemson, South Carolina.

Exercise prescription to improve cardiorespiratory endurance (CE) is often based on percentages of the reserve or maximum heart rate (HRpeak) or oxygen consumption rate (V̇O2peak)that reflect vigorous intensities (77-95% HRpeak, 64-90% V̇O2peak). These intensities elicit a rating of perceived exertion [RPE] response between 14-17 on the 6-20 Borg Scale. It is recommended that exercise within these ranges be sustained for 20-60min per session. The purposes of this study were to: 1) Determine the metabolic (V̇O2) and perceptual (RPE) responses as well as the sustainability of exercise (time to exhaustion [Tlim]) anchored to heart rates (HR) at the lower (HRL= 77% peak heart rate [HRpeak]), middle (HRM=86% HRpeak), and higher (HRH= 95%HRpeak) ends of the range recommended for vigorous exercise; 2) determine if the V̇O2 and RPE response remain within the recommended ranges for vigorous exercise throughout the trials at HRL, HRM, HRH by examining the time course of changes and patterns of responses for these variables as well as power output (PO), respiratory exchange ratio (RER), minute ventilation (E), and respiratory rate (RR) responses; and 3) determine the time spent in the severe (> respiratory compensation point [RCP]), heavy (< RCP, > ventilatory threshold [VT]), and moderate (< VT) intensity domains for the composite and on a participant-by-participant basis during each of the constant HR trials. Twelve, moderately trained, participants performed a graded exercise test to exhaustion on a calibrated cycle ergometer to determine the peak responses for HR (HRpeak), V̇O2 (V̇O2peak), RPE, RER, V̇E, RR,and peak power output as well as the VT and RCP. On separate days, constant HR trials were performed at HRL, HRM, and HRH, in a randomized order. The O2, RER, E, RR,power output (PO), RPE, and Tlim were examined during the randomly ordered continuous trials to exhaustion or up to 60 min. The HRL (143±8 beats×min-1 [b×min-1]), the HRM (159±8 b×min-1), and the HRH (176±9 b×min-1) were maintained for 53.42±13.19, 46.75±18.79, and 27.05±18.00 min, respectively, not including the time to reach the desired HR. A one-way repeated measures ANOVA (F=26.196, p ≤ 0.001, ηp2=0.704) and post-hoc, t-tests with a Bonferroni corrected alpha (p < 0.017) indicated the Tlim at HRL and HRM were both significantly longer than Tlim at HRH (p < 0.001), but Tlim for HRM and HRL were not different. Responses across time were examined with 3(Intensity: HRL, HRM, and HRH) x 10(Time: 10-100%Tlim) repeated measures ANOVAs and post-hoc analysis. The O2, collapsed across intensity, was significantly lower than the initial value (10%Tlim) from 20-100% Tlim (p < 0.001). The RPE, collapsed across intensity, was significantly higher than the initial value (10%) from 30-100% of Tlim(p=0.0001 to 0.0019). For HRL trial, the composite (average of all subjects across time) V̇O2 (53.9±7.1% V̇O2peak) and RPE (RPE of 12±3) responses were lower than the recommended range during the trials. For the HRM trial, the average V̇O2 (64±7% V̇O2peak) and RPE (RPE of 14±2) responses were within the recommended range for 40% (~19 min) and 70% of Tlim, respectively. For HRH trial, the average V̇O2 (80±8% V̇O2peak) and RPE (RPE of 17±1) responses were within the recommended range for the entire trial. On a participant-by-participant basis, the HRH was the only intensity where approximately half of the participants were within the recommended V̇O2 (58% of participants) or RPE (67% of participants) ranges for 20 min. An additional 3(Intensity: HRL, HRM, and HRH) x 10(Time: 10-100%Tlim) repeated measures ANOVAs and post-hoc analysis were performed for PO, RER, V̇E, and RR. The PO, collapsed across intensity, was significantly lower than the initial value (10%) from 20-100% of Tlim (p=0.0002 to 0.0014) for all comparisons. The RER at HRL, HRM, and HRL, were significantly lower than the initial value (10%) from 20-100% of Tlim (p=0.0001 to 0.0006). The RER for HRH was greater than HRL and HRM at most time points, however, there were no differences in RER between HRL and HRM. The V̇E, collapsed across intensity, was significantly lower than the initial value (10%) from 20-100% of Tlim (p=0.0001 to 0.0002) and the RR, collapsed across intensity, was significantly higher than the initial value (10%) from 70-90% of Tlim (p=0.0013 to 0.0019). The repeated measures ANOVA examining time in each intensity domain indicated there was a 2-way interaction (F =25.588, p ≤ 0.001, ηp2=0.699). The post-hoc t-tests indicated that at HRL, the participants spent significantly more in the moderate domain than the heavy (p ≤ 0.001) and severe (p ≤ 0.001). There was no significant difference in the time spent within the heavy and severe domains (p=0.053). At HRM, more time was spent in the moderate than the heavy (p=0.002) and severe (p ≤ 0.001) domains and there was more time spent within the heavy than the severe (p=0.010). Finally, at HRHthere were no significant differences between the time spent in the moderate compared to the heavy domain (p=0.318), severe (p=0.017), or between the heavy and severe (p=0.036). There were intensity specific metabolic demands that demonstrated the HRH elicited the highest metabolic cost and RER relative to HRM and HRL. The decreases in V̇O2 tracked PO and V̇E followed a similar pattern for each trial. The RPE increased during each HR trial and RR tracked this response. The increases in RPE may be attributed to an increase in the RR and feedback from mechanical and metabo-sensitive group III/IV afferent neurons. The O2 and RPE findings indicated that exercise anchored at HRL and HRM may not provide an intensity that meets the current guidelines for improving CE fitness. While HRH may be at a sufficient intensity to elicit the desired metabolic responses on average, it may not be for all participants. Thus, these data indicated that HRpeak should not be used to prescribe a desired metabolic intensity.

BACKGROUND: Spaceflight induces rapid loss of aerobic capacity and muscle strength. Flywheel-based Inertial Training (FIT) – a gravity-independent form of exercise previously used as a countermeasure against unloading-induced muscle atrophy – provides external resistance through moment of inertia (MOI) of a rotating disk in a velocity-dependent manner. Optimizing FIT for cardiorespiratory fitness may improve exercise efficiency and reduce hardware needs associated with deep space exploration. This modality of exercise has also been of interest among athletes of various disciplines due to its purported benefits on athletic performance. PURPOSE: To determine the cardiorespiratory and muscular recruitment responses to FIT with varying MOIs. METHODS: Twenty healthy, physically active participants (10M, 10F; age: 19-39y) completed two bouts of FIT squats (Exxentric Kbox 4Pro) separated by ≥7d. Testing consisted of quarter-squats (3 min per stage; 50 repetitions per minute) with increasing MOI increments of 0.005 kg·m2 until volitional fatigue. Squat depth (60° knee flexion) was monitored by a wireless electrogoniometer in real-time. Heart rate (HR) and gas exchange data were averaged over the final 60s of each stage. Surface electromyography (EMG) of the gluteus maximus (GM), vastus lateralis (VL), biceps femoris (BF), and soleus (SOL) were measured. EMG and electrogoniometer data were time-synchronized throughout testing and transmitted to a Trigno Avanti EMG system (Delsys, Natick, MA). Prior to FIT testing, subjects performed three reference isometric contractions in a squat position; all EMG data were normalized to this level of EMG activity. Inter-session reliability and reproducibility (Bland-Altman plots) were assessed. Mixed model 2x2 ANOVAs assessed cardiorespiratory and muscle recruitment responses to MOI (within subjects) for both sexes (between subjects). RESULTS: Mixed model ANOVA revealed a main effect of MOI on HR (p2 (p2 with males demonstrating greater values than females. When normalized to peak VO2, no effect of sex was noted. There was no significant MOI x sex interaction for any of the observed variables. There was a significant main linear effect of MOI on peak EMG amplitude, integrated EMG, and mean EMG amplitude during the eccentric phase for all muscles (p2 responses at any stage between trials one and two. CONCLUSION: FIT squats provide reliable cardiorespiratory data between testing sessions when performed at a standardized pace. Increasing MOI during FIT evokes a linear response in HR, VO2, and RER in males and females with no apparent effects of sex when normalized to peak values. The RER response (>1.0) at a relatively modest oxygen uptake (~60% VO2peak) suggests this modality stimulus compared to other forms of aerobic exercise. Increasing MOI during submaximal FIT squats evokes a linear response in peak EMG amplitude, mean ECC EMG amplitude, and iEMG of knee extensors, hip flexors, and plantar flexors. Increasing MOI increases mean CON EMG amplitude and ECC/CON ratio of the plantar flexors and hip extensors, but not the knee extensors. However, ECC overload was only evident in the knee extensors. At higher MOI, muscle recruitment of hip extensors and plantar flexors is preferentially increased, but eccentric overload is only achieved in the knee extensors. Future work should aim to determine how sustained FIT affects cardiorespiratory fitness.

Background: Accurate assessment of concussion is crucial for creating a treatment plan. The Buffalo Concussion Bike Test (BCBT) is a 30-minute graded exercise protocol for a stationary bicycle. Previously this assessment has been reportedly used to screen for exercise intolerance secondary to autonomic dysfunction; however, the original purpose of the assessment was to find a sub-symptom threshold for exercise rehabilitation during concussion recovery. Starting resistance for the BCBT protocol is based solely on body mass. Other factors such as cardiorespiratory fitness level and sex have been noted to effect outcomes on similar assessments and are not considered in the BCBT protocol or interpretation. Purpose: The primary purpose of this study is to determine the effects of cardiorespiratory fitness levels (CRF) on the time-to-test completion of the Buffalo Concussion Bike Test among adults with high and low CRF. The secondary purpose of this study is to document sex differences on time-to-test completion and heart rate at test completion on the BCBT. Study design: This study employed a cross-sectional, extreme groups approach study design. Methods: Forty-two healthy adults between 20-29 years of age (M = 22.31 ± 2.25 years) completed a VO2 max bike test at their first appointment to screen for eligibility and for placement into high and low groups. To assess for the effects of CRF level, only people with “excellent” and “superior” VO2 max scores were included in the HIGH CRF group (n = 21) and participants with “poor” and “very poor” VO2 max scores according to the American College of Sports Medicine cutoffs were included in the LOW CRF group (n = 21). Participants with “good” and “fair” VO2 max scores were excluded from the study. After eligibility was confirmed and they were assigned to their groups, participants completed the BCBT protocol within 3-14 days. Participants were also administered the Post-Concussion Symptom Scale (PCSS) and the Vestibular/Ocular Motor Screening (VOMS) immediately before and after the BCBT. Results: Participants in the HIGH CRF group exhibited longer times-to-test completion (U = 15.00, p Conclusions: Non-concussed individuals with high CRF levels exhibited a ceiling effect on the BCBT protocol. However, they did not exhibit significantly different scores on the PCSS before or after the BCBT compared to individuals in the low CRF group. Males and females did not differ on time-to-test completion or peak heart rate, additionally, they exhibited similar VOMS change scores before and after the BCBT protocol. The findings for the current study further support the literature on interpretation of exercise testing and highlight the need for CRF level considerations for the BCBT protocol.

Cognitive aging has profound effects on the hippocampus, a brain region that is critical for episodic memory formation and spatial navigation. Accurate episodic memory formation requires pattern separation, a neurocomputational process that orthogonalizes similar stimulus input into distinct neural representations and can be examined using behavioral mnemonic discrimination paradigms in humans. Age-related impairment in hippocampally-dependent cognition emphasizes the importance of identifying modulators of hippocampal plasticity. Critically, studies in older adults have demonstrated that greater cardiorespiratory fitness (CRF) is associated with greater volume of the hippocampus, mitigated age-related decline in spatial mnemonic discrimination, and better visuospatial memory. Nonetheless, how CRF modulates the underlying structural and functional neural correlates of mnemonic discrimination and spatial navigation in cognitive aging remains unknown. Therefore, the overall objective of this dissertation was to examine CRF as a modulator of hippocampal memory system structure and function, specifically regarding the hippocampally-dependent processes of mnemonic discrimination and spatial navigation, in cognitively healthy older adults. In a series of three experiments, we tested the central hypothesis that CRF enhances hippocampal plasticity and modulates the underlying neural correlates of mnemonic discrimination and spatial navigation in older adults. Data for these three experiments came from two studies. In the first, young adults (ages 18-35 years) and older adults (ages 55-85 years) underwent high-resolution fMRI to examine hippocampal subfield blood-oxygenation level-dependent (BOLD) signal during mnemonic discrimination. In the second, older adults (ages 60-80 years) underwent whole-brain, high-resolution fMRI to examine whole-brain BOLD signal during spatial navigation. In both studies, participants performed a submaximal treadmill test to estimate CRF and underwent high-resolution structural MRI to measure hippocampal subfield volumes as markers of neuroplasticity in the hippocampus. The primary goal of Experiment 1 was to examine the prediction that CRF is positively associated with mnemonic discrimination task performance and dentate gyrus (DG)/CA3 volume in older adults, given that these hippocampal subfields are thought to support pattern separation. Contrary to our initial prediction, we did not observe a relationship between CRF and mnemonic discrimination task performance or CRF and DG/CA3 volume. Instead, we observed a significant positive relationship between CRF and the volume of another hippocampal subfield, the bilateral subiculum, in older adult women, but not men. The primary goal of Experiment 2 was to examine the prediction that mnemonic discrimination-related BOLD signal in the hippocampal subfields is modulated by aging and CRF in young and older adults. In line with our initial prediction, there was a significant difference between young and older adults in right DG/CA2-3 BOLD signal during mnemonic discrimination task performance. Most importantly, CRF significantly modulated bilateral subiculum BOLD signal in an opposing fashion in young and older adults. The primary goal of Experiment 3 was to extend the current study beyond the function of the hippocampus in isolation and to examine whole-brain activation in association with an ecologically valid task that engages a large network of brain regions including but not limited to the hippocampus. We predicted that CRF modulates BOLD signal activation patterns driven by the employed spatial navigation task, specifically in brain regions in the frontal, parietal, and temporal cortices, and the cerebellum, given that the previously published literature in older adults has suggested that CRF enhances structural integrity in these regions in addition to the hippocampus. Our results demonstrated that CRF is significantly positively associated with BOLD signal in the right cerebellum lobule VIIa Crus I and Crus II, a region that has been implicated in sequence-based navigation. And, consistent with our results from Experiment 2, this relationship was observed in older adult women. Importantly, the findings of these experiments highlight novel targets of fitness-related neuroplasticity in the older adult brain, including the subiculum subfield of the hippocampus and the cerebellum lobule VIIa Crus I and Crus II. Furthermore, these findings underscore the importance of examining sex as a modulating factor of fitness-related neuroplasticity.

The purposes of this study were to: 1) Determine if there are differences in the sustainability of exercise when anchored at critical heart rate (CHR), the VO2 associated with CHR (VO2CHR), or the power output associated with CHR (PCHR); 2) examine the patterns of responses in power output, metabolic (heart rate [HR], VO2, respiration rate [RR]), neuromuscular (electromyographic [EMG] amplitude [AMP], mean power frequency [MPF], mechanomyographic [MMG] AMP and MPF, perceptual (rating of perceived exertion [RPE]), and muscle oxygenation responses (%SmO2) during exercise anchored by HR, VO2, and power output; and 3) determine if the CHR can be used for exercise prescription based on time to exhaustion (TLim), physiological, perceptual, and neuromuscular responses. Six, moderately trained, subjects performed a graded exercise test (GXT). On separate days, 4 constant power output trials were performed in a randomized order at 85%, 90%, 95%, and 100% of the peak power output (PPO) determined from the GXT. The total number of heart beats (HBLim) for each power output was calculated as the product of the average 5-second HR and TLim for each constant power output trial. The CHR was defined as the slope of the linear regression of the HBLim versus TLim relationship. The VO2CHR was derived from the linear regression equation of the VO2 versus HR relationship from the GXT where VO2CHR was defined as the VO2 corresponding to CHR. Similarly, the PCHR was derived from the linear regression of the power output versus HR relationship from the GXT where the PCHR was defined as the power output corresponding to CHR. The physiological, perceptual, and neuromuscular responses were recorded during trials at CHR, VO2CHR, and PCHR. Polynomial regression analyses were used to examine the patterns of responses for all variables. The HBLim versus TLim (r2 = 0.9946-0.9995), the VO2 versus HR (r2 = 0.8833 – 0.9899), and the power output versus HR (r2 = 0.9600 – 0.9886) relationships were highly linear. The CHR (170 ± 9 beats×min-1, 91 ± 5% HRmax), VO2CHR (31.55 ± 7.85 mL×kg-1×min-1, 81± 10% O2peak), and PCHR (199 ± 70 Watts, 75 ± 11% PPO) were maintained for 46.28 ± 18.49, 28.93 ± 24.41, 22.60 ± 21.61 min, respectively. At CHR, there was no change in HR, quadratic decreases in VO2 (R2 = 0.976) and power output (R2 = 0.900), quadratic increases in RR (R2 = 0.590), EMG MPF (R2 = 0.986), and MMG MPF (R2 = 0.739), linear increases in RPE (r2 = 0.960), %SmO2 (r2 = 0.940), and MMG AMP (r2 = 0.921), and linear decreases in EMG AMP (r2 = 0.935). At VO2CHR, there was no change in EMG AMP, MMG AMP, and MMG MPF, quadratic decreases in power output (R2 = 0.810), quadratic increases in RPE (R2 = 0.964), linear decreases in VO2 (r2 = 0.580) (despite VO2start = 31.15 mL×kg-1×min-1 not being different from VO2end = 30.85 mL×kg-1×min-1), and linear increases in HR (r2 = 0.860, RR (r2 = 0.940), %SmO2 (r2 = 0.390), and EMG MPF (r2 = 1.000). At PCHR, there was no change in power output, and MMG AMP, quadratic decreases in EMG MPF (R2 = 0.700), quadratic increases in VO2 (R2 = 0.839), HR (R2 = 0.960), and RPE (R2 = 0.996), linear increases in RR (r2 = 0.990), and EMG AMP (r2 = 0.500), and linear decreases in %SmO2 (r2 = 0.720), and MMG MPF (r2 = 0.547). These findings indicated the CHR was more sustainable than VO2CHR and PCHR, and may provide a suitable stimulus for cardiorespiratory endurance training.

Background: Breast cancer patients commonly experience weight gain and increased central adiposity following cancer treatment. Prior research has not investigated the extent to which psychological factors predict longitudinal changes in body composition among cancer patients. Elevated depressive symptoms, which are common after breast cancer surgery, may contribute to increased central adiposity via decreases in cardiorespiratory fitness. Chemotherapy treatment has been tied to weight gain and impaired cardiorespiratory functioning in prior research, and may also lead to increased central adiposity. Aims: The study investigated the effect of post-surgical depressive symptoms on two-year changes in central adiposity. The effect of chemotherapy treatment, including chemotherapy type and dose intensity, on central adiposity changes was also evaluated. Cardiorespiratory fitness was tested as a mediator of changes in central adiposity. Methods: Breast cancer patients (N=111), stages I-IIIa, provided data at two time points: after surgery but prior to starting adjuvant treatment and two years after completion of adjuvant treatment. At each time point, participants underwent a DXA scan to measure central adiposity and completed a graded exercise test measuring their cardiorespiratory fitness. They also provided self-report data regarding their depressive symptoms (Center for Epidemiologic Studies Depression Scale), fatigue (Multidimensional Fatigue Symptom Inventory), sleep problems (Pittsburgh Sleep Quality Index), pain (bodily pain subscale of the RAND 36-Item Short Form Health Survey), diet quality (Diet History Questionnaire II), and physical activity level (Godin-Shephard Leisure Time Physical Activity Questionnaire). Information regarding participants’ chemotherapy treatment was obtained using electronic medical records. Results: Breast cancer patients showed significant increases in central adiposity over the follow-up period. Women with greater depressive symptoms after breast cancer surgery had marginally greater increases in trunk fat mass compared to those with fewer symptoms. However, this relationship was no longer significant after including sleep problems and pain in the models. Chemotherapy treatment was not associated with differential changes in central adiposity, nor was chemotherapy dose intensity or regimen type. Contrary to hypotheses, women did not show significant changes in cardiorespiratory fitness over time. Additionally, fitness changes did not serve as a mediator in the relationship between depressive symptoms and central adiposity change or in the relationship between chemotherapy treatment and adiposity. Conclusions: Results provide preliminary evidence that depressive symptoms may impact changes in central adiposity during breast cancer survivorship; however, effects are likely small and may be driven by sleep disturbances and increased pain. While chemotherapy was not associated with changes in central adiposity in this sample, other studies indicate that some women remain vulnerable to chemotherapy-related increases in visceral fat. Results of the current study are reflective of significant heterogeneity in the literature examining predictors of weight gain and increased abdominal fat in breast cancer survivors. These inconsistencies point to a need for future research assessing clinical and demographic factors associated with within-person differences in body composition change during breast cancer survivorship, especially among vulnerable populations.

The purpose of this study was to determine the reliability and validity of the 30-15 Intermittent Field Test (30-15IFT) with and without a ball and to determine differences across these two methods in female soccer players. Twenty-four collegiate female soccer players participated in this study (19.46 ± 1.22 years; 167.01 ± 7.23 cm; 60.95 ± 7.84 kg). Players performed one trial of the Yo-Yo Intermittent Recovery (YYIR) test, three trials of the 30-15IFT, and three trials of the 30-15IFT with a ball (30-15IFT-B), separated by a minimum of 48 hours. Maximal intermittent running velocity (VIFT), heart rate at exhaustion (HRpeak), and rating of perceived exertion (RPE) were collected. Interclass correlation coefficients (ICCs) demonstrated good reliability during the 30-15IFT in VIFT (ICC = 0.88) and HRpeak (ICC = 0.89), as well as in the 30-15IFT-WB VIFT (ICC = 0.83) and HRpeak (ICC = 0.87). Results showed differences between VIFT, HRpeak, and RPE between trials 30-15IFT and 30-15IFT-B (p < .05). Significant differences were shown in mean VIFT scores between trials 1 and 2 (p < .001) and trials 1 and 3 (p < .001). Estimated maximal oxygen consumption (VO2max) of YYIR and estimated VO2 max of 30-15IFT and 30-15IFT-WB was very strongly (r = 0.82) and strongly (r = 0.68) correlated. In conclusion, the 30-15IFT was deemed valid and reliable and the 30-15IFT-B was reliable in female soccer players.

One of the earliest symptoms of Alzheimer’s disease (AD) and age-related cognitive decline is topographical disorientation or impairment to spatial navigation. Furthermore, aging and AD are associated with cortical gray-matter thinning, particularly in the medial temporal and posterior cingulate regions, which have been associated with spatial navigation. Aerobic exercise has been well-established as a beneficial intervention to curtail the neurodegenerative effects of aging. This study aims to explore the relationship between cardiorespiratory fitness (CRF), and two markers of AD and cognitive aging, virtual navigation ability and cortical thickness of the entorhinal, parahippocampal and retrosplenial regions. Cross-sectional data utilized in this study was collected from 23 healthy older adults (60-80 years). Measures included in our analyses consisted of estimated VO2max, T1-weighted structural MR images, and behavioral performance on a virtual navigation task, measured as numbers of objects located during recall. Cortical thickness of the regions of interest (ROIs) was determined by processing T1-weighted MR images in FreeSurfer. We hypothesized that greater CRF would correlate with improved virtual navigation performance and greater cortical thickness of ROIs. Our analyses did not reveal statistically significant relationships between CRF and navigation performance or CRF and cortical thickness. However, Pearson’s correlations found right retrosplenial cortical (RSC) thickness and navigation performance to be significantly related. Multiple regression models of right RSC thickness and navigation performance were performed controlling for age, sex, education and task version. These analyses revealed that greater right RSC thickness predicted navigation performance. Additionally, this model showed that older age predicts decline in navigation performance. Our findings did not survive multiple comparisons correction; nonetheless, the results provide promising insight to the relationship between cortical thickness and navigation performance in healthy aging. Further cross-sectional and longitudinal investigations with a larger sample size are required to assess the impact of CRF and exercise on cortical thickness and navigation abilities in healthy aging. Understanding these relationships would contribute to the expansive body of literature that has linked CRF and exercise to neuroprotective mechanisms in the aging brain.

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.

As the survival rate for childhood cancer increases, the cost of cure leaves this population at-risk for developing cardio-metabolic late-effects during survivorship. Yet, the understanding of the potential for health protective behaviours including physical activity and cardiorespiratory fitness to mitigate this risk among childhood cancer survivors (CCS) remains limited. Using a mixed-methods approach, this dissertation aimed to establish physical activity behaviours and the resulting fitness among CCS. I identified that the majority of 570 CCS (73% children, 70% adults) from early to late survivorship from 11 Australia/New Zealand paediatric oncology hospitals did not meet recommended physical activity guidelines from self-reported questionnaires. I investigated cardiorespiratory fitness in 216 CCS, a modifiable risk-factor for cardiovascular disease. I developed an algorithm using their performance from a 6-minute walk test, waist-to-height ratio, age and sex to predict their maximal oxygen consumption (gold-standard fitness measure). Using this algorithm, I established that mean fitness levels among 102 CCS was low (37th percentile). I identified that CCS reported fatigue, preferring TV and lacking time as physical activity barriers, whilst active survivors were more likely to exercise with friends. I explored the acceptability of an exercise physiology consultation including individualised prescription among 70 families. I found that parents were more satisfied with the physical activity information they received during this consultation compared with their usual care. Nearly all parents and survivors expressed the need for additional consultations for themselves and future CCS. Despite the demand for physical activity support, logistical barriers including distance to hospital facilities significantly affect the feasibility of supervised physical activity interventions. Hence, I conducted a systematic review and meta-analysis exploring the feasibility and effect of distance-delivered physical activity interventions (e.g. telephone, internet, mobile applications) among CCS. Among 13 studies, I found the majority of CCS adhered to prescribed physical activity and remained in programs. Among 4 randomised studies, participating in distance-delivered interventions yielded improvements in physical and psychological health. In conclusion, I have demonstrated that CCS require support to increase physical activity and cardiorespiratory fitness to mitigate their already increased risk of developing medical late-effects.

Alzheimer’s disease (AD) is a rapidly growing public health concern causing severe challenges to the health care system. Affecting the lives of more than 5 million Americans, it is characterized by brain-related morphological changes coupled with decrements in performance on tasks involving cognitive function such as those assessing memory and problem-solving abilities. Fortunately, current scientific research provides evidence that this trend towards rapid cognitive decline in older adults is not immutable, but rather can be attenuated through a simple adjustment to regular engagement in aerobic exercise. To date, numerous studies have associated regular cardiovascular exercise to changes in brain function and structure. In particular, aerobic exercise has been shown to have a direct effect on the hippocampus (HC), one of the earliest regions of the brain to be affected in AD, which plays an important role in learning and memory. Scientific research on animal models has demonstrated increased adult hippocampal neurogenesis (AHN), or the birth of new neurons, in the dentate gyrus (DG) subregion of the hippocampus as a response to increases in aerobic exercise. Such findings have led to the hypothesis that aerobic exercise can improve cognitive performance, more specifically hippocampal-dependent learning and memory, through the formation of new hippocampal neurons. Similarly, in human studies, previous research has shown that significant improvements in cardiovascular fitness are positively correlated with increased hippocampal volume. Structural increases in hippocampal volume are thought to be mediated by increased angiogenesis, or the generation of new blood vessels, which in turn are correlated with significant improvements in spatial memory, a task determined by memory function. The benefits of aerobic exercise, nonetheless, are not limited to the hippocampus. As people age, atrophy of the brain is also inclusive of the prefrontal cortex, a region implicated in planning and decision making. Scientific literature has shown, that similar to the hippocampus, increases in aerobic exercise, directly result to increases in grey matter volume in the prefrontal lobe and increases in white matter volume in the genu of the corpus callosum. Such structural changes in the prefrontal lobe are correlated with enhanced decision making on cognitive tasks, an essential component of executive function. For the purposes of this study, an effective method of evaluating whether changes in brain structure due to higher cardiorespiratory fitness have an association with cognitive function was through the administration of the Digital Clock Drawing Test (dCDT). The dCDT is a recently developed cognitive test based on the traditional Clock Drawing Test (CDT) that uses a digital pen and allows for the measurement of several parameters such as “Ink time” and “Think time.” Recent scientific studies report that such parameters may have a potential enhanced sensitivity to detecting cognitive change as compared to the traditional CDT. Therefore, the dCDT has come forward as an advantageous approach for testing cognitive skills in aging individuals such as those assessing executive and motor function, and semantic memory, as it happens in real time. DCDT parameters such as total time to complete the clock drawing, total ink time, total think time, total ink length, and clock size have been shown to differ significantly among subjects of varying degrees of cognitive impairment such as AD, mild cognitive impairment (MCI), and healthy, non-demented controls. Patients who were clinically diagnosed as cognitively impaired spent a greater amount of time thinking and drawing on both the command and copy clocks conditions as compared to healthy, non-demented individuals. Similarly, patients affected by greater cognitive impairments, such as AD, tended to draw smaller clocks in terms of height and width of the clock face that required less total ink length to complete the clock drawing, when compared to healthy controls and MCI participants. Findings showed that AD patients appeared to be working longer (greater time of completion) though producing less output (smaller clock and shorted ink length) as compared to non-impaired individuals. Variations of graphomotor latencies in the dCDT performance, therefore, are associated with individual’s cognitive capacities. The goal of this study is to investigate the associations between cardiorespiratory fitness based on VO2 max testing and cognitive constructs such as memory, executive function, and gross motor processing speeds as measured by graphomotor latencies and drawing patterns using the dCDT in healthy, non-demented older adults. I hypothesize that greater cardiorespiratory fitness will be negatively associated with graphomotor timed latencies in various parameters of the dCDT, given that exercise has known effects on the brain regions responsible for executive function and memory. To test these hypotheses, cardiorespiratory fitness and dCDT data from 12 sedentary older adults between the ages of 55 and 85 years from a larger study in the Brain Plasticity and Neuroimaging Laboratory at Boston University were collected and analyzed. A multiple regression analysis was used to predict the dCDT measures from individual’s cardiorespiratory fitness using estimated VO2 max levels. Results showed that cardiorespiratory fitness in older adults is inversely associated with graphomotor times in both the command and copy test conditions as predicted by our hypothesis. In particular, greater cardiorespiratory fitness was associated with shorter total ink time for both clock drawing testing conditions. These results held when controlled for age, sex, and education; higher cardiorespiratory fit older adults performed better (a shorter time is needed to achieve the same outcome) on tasks requiring greater cognitive constructs such as memory, executive function, and motor processing speeds. Therefore, it can be concluded that cardiorespiratory fitness may be a neurodegenerative protector in aging adults supporting its beneficial role as a therapeutic agent for cognitive decline in older adults.

Background: Cardiorespiratory fitness (CRF) is one of the most important components of physical fitness. Low levels of CRF are associated with high mortality risk. Objective: To investigate factors associated with CRF in postmenopausal women with prehypertension. Methods: A descriptive design was used in this study. Through purposive sampling, 84 postmenopausal women with prehypertension were recruited from Ratchaburi province. The data were collected by using the structured questionnaire with face-to-face interview. All of the participants were measured for CRF (estimated maximal oxygen uptake [VO2max]). Data were analyzed using descriptive and inferential statistics. Results: The results revealed that mean age of participants was 55.15 ± 7 years (range, 44 - 69 years). Most of them were married (69%), obtained primary education (76.2%), worked as farmer (76.2%), and none farmers (23.8%). Approximately half of them did not exercise (42.9%). CRF was associated with waist circumference (rp = -0.637, P < 0.001), body mass index (rp = -0.562, P < 0.001), heart rate (rp = -0.581, P < 0.001), and occupation (rs = 0.396, P < 0.001). Conclusions: Factors including waist circumference, body mass index, and heart rate were negatively associated with CRF in postmenopausal women with prehypertension. The results suggest approaches for healthcare providers to develop programs promoting cardiorespiratory fitness among postmenopausal women with prehypertension to enhance their health status and prevent hypertension and cardiovascular risk factors.

Prevalence of physical inactivity in children and adolescents and the associated epidemic of obesity are increasing concerns. U.S. national health statistics indicate early adolescence (i.e., 10-14 years) appears to be a period of importance regarding physical activity, sedentary behavior, health-related physical fitness, and obesity trends. Considering a significant portion of their waking hours are spent in school, it is widely held that schools' should play a significant role in increasing students' physical activity and health-related physical fitness. To do this, physical education in schools focus on providing quality physical education programs that produce physically literate individuals who have the knowledge, skills, and confidence to enjoy a lifetime of health-producing physical activity. In effect, a call for developing a comprehensive and valid measure of physical literacy has been aptly expressed. Thus, the purpose of this dissertation was to test the psychometric properties of proposed models of physical literacy, examine correlates of the physical literacy factor, and investigate the significance of the relationship between physical literacy and interscholastic sport intention via structural equation modeling. Participants were 400 (231 female, 169 male) sixth-grade physical education students who completed three brief surveys assessing maturation, self-efficacy, self-esteem, knowledge and understanding, motivation, physical activity and sport participation, and interscholastic sport intention. In addition, students completed a sedentary behavior log, a health-related physical fitness assessment, and an overhand throwing skill assessment. Analyses offered overall support for the proposed physical literacy measurement models. Results also supported positive relationship Physical literacy was statistically significantly positively related physical activity and sport team participation, and significantly negatively related and screen-time sedentary behavior. Results also supported a positive path between physical literacy and interscholastic sport intention. The implications of promoting physical literacy within physical education are discussed in light of the three higher-order underlying factors of physical literacy.

Background: Breast cancer survivors commonly experience cognitive problems following cancer and its treatment. Although prior research focused on chemotherapy-related cognitive impairment, newer studies suggest that some women also experience cognitive problems prior to chemotherapy and radiation treatments. Accordingly, factors besides cancer treatment may also influence breast cancer survivors' cognitive function. Physical fitness benefits cognitive function in healthy adults, and breast cancer survivors experience declines in fitness even prior to adjuvant treatment. Aims: The study investigated the extent to which cardiorespiratory fitness (CRF) impacted cognitive function among post-surgery breast cancer survivors prior to chemotherapy and radiation treatment, and examined the potential psychological pathways for this relationship. The prospective effect of cognitive function on adherence to chemotherapy and radiation treatments was also evaluated. Methods: Following cancer surgery but before chemotherapy or radiation treatments, stage I through IIIA breast cancer survivors (n = 90, ages 26 to 75) completed neuropsychological tasks of verbal memory (Hopkins Verbal Learning Test), verbal fluency (FAS), executive function (Trail-Making Test, n-back task), and sustained attention (Conners Continuous Performance Test) in the context of a larger observational study. They also underwent a graded cycle ergometry test to measure peak oxygen consumption (VO2peak), and reported their depressive symptoms (Center for Epidemiologic Studies Depression Scale), anxiety symptoms (PROMIS Anxiety Scale), and sleep problems (Pittsburgh Sleep Quality Index). Chemotherapy and radiation treatment adherence was measured by concordance with National Comprehensive Cancer Network (NCCN) standards as well as the number of treatment appointments that were missed/cancelled by the patient, using medical record data. Results: CRF did not concurrently benefit performance on verbal fluency, executive function, and sustained attention tasks. Although women with better fitness had higher immediate verbal memory scores than those with poorer fitness, this relationship was no longer significant when controlling for age, education, cancer stage, medical comorbidities, and time since surgery. There were not fitness-related differences in depressive symptoms, anxiety symptoms, or sleep problems, which did not individually or collectively mediate the relationship between CRF and cognitive function. Few participants missed any appointments (n = 11) or received inadequate treatment by NCCN standards (n = 10). Women with poorer attentiveness (indexed by CPT omissions) following surgery were subsequently more likely to miss or cancel a treatment appointment compared to women with higher attentiveness (OR = 1.265, 95% CI = 1.008 to 1.587). However, those with poorer executive function (indexed by n-back RT cost) were less likely to miss or cancel an appointment than those with better executive function (OR = .014, 95% CI = .000 to .978), an unexpected finding. Women's post-surgery verbal memory and verbal fluency did not impact their appointment attendance. Conclusions: There were not consistent, clear links between cognitive function, cardiorespiratory fitness, and chemotherapy/radiation adherence in this sample of relatively healthy, well-adjusted women following breast cancer surgery. Although physical fitness did not appear to benefit cognitive function in this study, breast cancer survivors gain many other health advantages from being physically fit throughout the disease continuum. Increased research focus on the post-surgery period will help to determine the underpinnings of pre-treatment cognitive dysfunction and decreased fitness, as well as characterize the relevance of these problems to clinical and real-world outcomes in breast cancer survivorship.

Around the world Alzheimer’s Disease (AD) is on the rise. Previous studies have shown the default mode network (DMN) sees changes with AD progression as the disease erodes away cortical areas. Aerobic exercise with significant increases to cardiorespiratory fitness could show neuro-protective changes to delay AD. This study will explore if functional connectivity changes in the DMN can be seen in a young adult sample by using group independent component analysis through FSL MELODIC. The young adult sample of 19 were selected from a larger study at the Brain Plasticity and Neuroimaging Laboratory at Boston University. The participants engaged in a twelve-week exercise intervention in either a strength training or aerobic training group. They also completed pre-intervention and post-intervention resting-state fMRI scans to evaluate change in functional connectivity in the default mode network. Cardiorespiratory fitness was assessed using a modified Balke protocol with pre-intervention and post-intervention VO2 max percentiles being used. Through two repeated-measure ANOVA analyses, this study found no significant increase in mean functional connectivity or cardiorespiratory fitness in the young adult sample. While improvements in mean VO2 max percentile and functional connectivity would have been seen with a larger sample size, this study adds to the literature by suggesting if fitness does not improve significantly, neither will functional connectivity in the default mode network.

BACKGROUND: Over recent decades, the nationwide prevalence of chronic disease among children and adolescents has been on the rise. Conditions such as obesity pose a significant risk to the physical and mental health of individuals in youth as well as in adulthood, as these health risks track into later years and increase in severity. Low-income and racial/ethnic minorities are disproportionately affected by chronic conditions. In particular, African American (AA) youth are reported to have a higher prevalence of fair/poor health than their Caucasian peers. Compounding the effects of this racial disparity in health is the disparity AA youth face in SES, as many live in poverty. The individual and environmental influences associated with factors of race and SES contribute to negative health behaviors leading to poor health status among AA youth living in disadvantaged communities. Health disparities have been shown to manifest in the earliest years of life, therefore the monitoring of at-risk populations of children and adolescents is essential to identifying, addressing, and reducing poor health outcomes throughout the course of life. OBJECTIVE: To determine the health status of AA children and adolescents living in a low-income community using multiple health measures, examine the relationships between these health measures in AA youth, as well as to identify barriers to participation in a family-oriented health promotion program. METHODS: A total of 111 AA boys and girls attending a community fine arts program located in a low-income suburb of Chicago participated in the study. Data from anthropometric measurements, the 20-m Shuttle Run Test, and curl-ups were collected and analyzed to assess the health measures of Body Mass Index (BMI) and BMI Percentile, Cardiorespiratory Fitness (CRF), and Muscular Fitness (MF), respectively. Data pertaining to barriers encountered in attending a health promotion program were collected from 13 families who were active members of the community fine arts program and had participated in health promotion program. The cross-sectional survey consisted of questions pertaining to the different components of the intervention program as well as to family demographic information. RESULTS: The prevalence of overweight and obesity in the entire study population was 34.2%, with 31.6% of boys and 34.8% of girls being classified as overweight/obese. 16.2% of youth categorized specifically as obese, with 26.3% of boys and 15.2% of girls being obese. 43.9% of study participants aged 10-18 years needed improvement in CRF, all of whom were girls. All but one boy reached the healthy fitness zone for curl-ups. Significant positive correlations were found between BMI and age as well as curl-ups and age, and significant negative correlation was found between CRF and age as well as BMI and CRF for AA youth. Of reported barriers, scheduling conflicts and time constraints were consistently most listed by survey respondents. CONCLUSION: Within the at-risk population of AA youth studied, despite high levels of MF, a large proportion presented with problematic health as indicated by the high levels of poor CRF and weight status observed, suggesting a need for intervention in order to address these health issues. An intervention program targeting youth within this and similar communities should take into consideration attenuating excessive program-associated expenses as well as offering more scheduling options and information on efficient food preparation and exercise.

This dissertation is composed of two manuscripts assessing cardiovascular disease (CVD) risk in structural firefighters. Study 1 compared traditional CVD risk factors and health-related behaviors between professional and volunteer firefighters. Online questionnaires were sent to approximately 4000 firefighters in the state of Kentucky. The results indicated that 90% of volunteer and 58% of professional firefighters were classified as moderate-to-high CVD risk. Volunteer firefighters were significantly (p < 0.001) older and more likely (p = 0.026) to be current cigarette smokers. The mean body mass index among all firefighters in the sample was 30.8 kg·m-2. Nearly 60% of volunteer firefighters were obese. Obese firefighters were more likely (p < 0.05) to have been diagnosed as diabetic or pre-diabetes compared to overweight and normal weight firefighters. These results indicate that volunteer firefighters may be at a greater CVD risk compared to professional firefighters. Study 2 investigated the association of cardiorespiratory fitness (CRF) and body fat with arterial stiffness in professional firefighters. Forty-six male professional structural firefighters performed a maximal graded exercise test in personal protective equipment and noninvasive arterial stiffness assessments before and for 60 minutes post-exercise. Percent body fat was measured with a bioelectrical impedance analyzer. Firefighters were stratified into fit (VO2peak ≥ 48.3 ml·kg-1·min-1) and unfit (VO2peak < 48.3 ml·kg-1·min-1) groups. Pulse wave velocity, an indicator of arterial stiffness, was significantly lower overall in the fit group compared to the unfit group (p < 0.001). However, the fit group had significantly less relative body fat compared to the unfit group. Thus, when controlling for the confounding effects of fatness, the results indicated that there was a significant effect of relative body fat (p < 0.001) but no effect of fitness on arterial stiffness (p = 0.490). This indicated that relative body fat was responsible for the difference in arterial stiffness and not the fitness stratification. The unfit group displayed a significantly higher average carotid-femoral pulse wave velocity of 1.004 m·s-1 which may increase the risk of a sudden cardiac event by 14%. In addition, there was no main effect for time (p = 0.794) or group x time interaction (p = 0.906). Most resting measures of central and brachial pressure were significantly higher in the unfit group. Results from this dissertation indicated that volunteer firefighters have a greater CVD risk than professional firefighters. Furthermore, relative body fat has a greater effect on arterial stiffness than cardiorespiratory fitness. Collectively, these findings indicate the need for innovative weight management strategies to decrease CVD risk among structural firefighters.

Adolescence is a developmental period during which boys and girls are at high risk of developing major or minor depression. Increases in fitness have been associated with lower levels of depressive symptomatology and improvements in psychological well-being, yet the mechanisms that underlie this relationship have not been thoroughly examined. Three such psychosocial variables (i.e. body satisfaction, social physique anxiety, and physical activity self-efficacy) have been identified as possible mechanisms and although they have theoretical support, additional research is needed to demonstrate empirically the potential effects of these variables. Self-report measures were used to assess the psychosocial variables and the Progressive Aerobic Cardiovascular Endurance Run (PACER) in conjunction with age, Body Mass Index [BMI], and sex was used to determine an estimate of aerobic capacity (VO2max). Path analyses were used to test the proposed model using version 6.2 EQS Multivariate Software. Results of study revealed that the boys’ and girls’ depressive scores were determined based on the extent that their fitness levels improved their satisfaction with their bodies and lowered the anxiety they experience in relation to real or imagined judgments of their physique. Although all pathways in the model were significant, with the exception of physical activity self-efficacy to depression, differences emerged between the boys and girls in terms of the strength of some of the relations amongst the variables. Limitations include restricted generalizability, self-report measures, and cross-sectional design. Results have implications for individuals in a context intended to improve physical and psychosocial well-being of adolescents.

A criterion method to evaluate cardiorespiratory health is measuring peak oxygen consumption (VO2 peak) from a maximal graded exercise test (GXT). While VO2 peak is a valuable measure, heart rate recovery (HRRec) and endothelial function (EF) also describe cardiorespiratory health and fitness. The purpose of this study was to investigate whether differences exist in VO2 peak, HRRec, and EF between healthy-weight (HW) and obese (OB) women and children and to determine if there were significant correlations among these variables. A total of 60 women and children participated in this study. Anthropometric, body composition, resting heart rate and blood pressure (BP) were measured. EF was evaluated to determine the reactive hyperemia index (RHI). Finally, each subject performed a graded exercise test (GXT) to determine VO2 peak. Following the GXT, the subjects’ recovery responses were monitored for 5 minutes. A factorial MANOVA was used to evaluate differences between obesity status and age in relative VO2 peak and relative HRRec. The MANOVA resulted in a significant (p < 0.001) main effect for obesity status and age, but there was no interaction effect. HW individuals had a greater relative VO2 peak compared to OB individuals. Children had a greater relative VO2 peak and HRRec compared to adults. Absolute VO2 peak and absolute HRRec were examined using univariate ANOVAs. Women had greater absolute VO2 peak values compared to children (p2 peak and absolute HRRec, relative HRRec, and RHI. Relative VO2 peak was significantly correlated to RHI. Absolute HRRec was correlated with relative HRRec and RHI. Relative HRRec was correlated with RHI. Lack of significant differences in HRRec and EF across adiposity levels were likely due to the obese, but otherwise healthy population recruited for this study. Age affected the response to all variables included in this study.

The current study examined the relationship between cardiorespiratory fitness on differences by sex, race/ethnicity, and SES on BMI, depressive symptoms, and school absences among adolescents. a cross-sectional study was conducted in a north Texas school district, which included 609 Caucasian/Whites, 293 Hispanic/Latinos, and 113 African-American/Black adolescents (10-14 years). Main results of the study showed that that cardiorespiratory fitness was the largest predictor of BMI, followed by race/ethnicity, and then sex. Cardiorespiratory fitness among adolescents was inversely associated with BMI. the relationship between cardiorespiratory fitness on BMI appeared to be more salient for non-Hispanic white females and non-Hispanic black females in that the former group had lower BMI scores than the latter group when cardiorespiratory fitness was taken into account; however, results showed that non-Hispanic white females and non-Hispanic black females had similar cardiorespiratory fitness level. Other results showed that SES and sex predicted depressive symptoms in that low SES females endorsed more depressive symptoms relative to high SES males; however, this relationship was non-existent when cardiorespiratory fitness was entered into the model. Additionally, findings indicated that BMI and depressive symptoms equally predicted school absences in that adolescents who had a higher BMI and endorsed more depressive symptoms had more school absences.

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.

The rising trend in cardiovascular disease is made evident by the drastic increase in health care costs as more and more people seek medical attention for coronary heart disease, atherosclerosis, heart attack, and stroke. This disease is further exacerbated by cigarette smoking which increases inflammation and has been proven to cause cancer. The focus to combat this disease has shifted away from treatment and towards prevention as people are realizing the benefits of exercise on all aspects of health. While the benefits of aerobic exercise are well-documented, resistance training (RT) as a means to counteract the markers of cardiovascular disease is not as well understood. The current study exams the effect of a 12-week periodized RT intervention and nicotine replacement therapy (NRT) on the fitness level and body composition in a population of young sedentary smokers. The subjects were randomized into four groups: RT and NRT, only RT, only NRT, or into the control group which received neither RT nor NRT. Participants were young (age 24.5 ± 4.6 yr), sedentary smokers. The control group had no significant drop in BMI and weight compared to the RT/NRT and RT groups. The RT/NRT group had a significant decrease in total fat, trunk fat, and fat percentage. The RT group had a significant increase in CRF measures compared to the other groups. Relative maximum aerobic capacity increased from 27.4 ± 3.05 ml/kg/min to 30.8 ± 2.12 ml/kg/min. This was significantly greater than the improvement seen in the NRT group (P < 0.05). The improved absolute maximum aerobic capacity and maximum breathing frequency were greatest in the RT group than in the NRT/RT, NRT, and Control groups. There was no significant difference between the changes in maximum heart rate. NRT/RT and RT groups had significantly greater improvements in 1-RM for chest press, leg press, and seated row as well as the composite RM as compared to the NRT group. The body mass index between the healthy cohort (HC) (23.17 ± 3.0) and smokers (25.05 ± 5.60) was not significantly different, neither was the height, weight, nor age. However, the body composition between these two groups was significantly different in all values analyzed. Total fat in the HC was 11.22 ± 10.97kg while smokers had a total fat of 18.06 ± 10.97kg. Trunk fat was measured at 4.69 ± 2.22kg in the HC and 7.90 ± 6.30kg in the smokers. There was a significant difference between body fat percentage with the smokers having and average of more than 5% higher than the HC and lean body mass was significantly lower for smokers as well.

In this study twenty-two commercial real estate salespeople were randomly assigned to one of four experimental conditions: (1) pretest, training, posttest; (2) pretest, no training, posttest; (3) no pretest, training, posttest; (4) no pretest, no training, posttest. The training groups participated in a monitored aerobics training program designed by the Institute for Aerobics Research, Dallas, Texas. In conclusion, it appears that an improvement in employee cardiorespiratory fitness does not necessarily lead to an improvement in job satisfaction or job performance. It is important to note, however, several possible explanations for these results. First, the pretest scores for the Job Descriptive Index were already quite high indicating there was not much room for improvement on posttest scores. Secondly, with regard to performance scores the; small number of subjects may have contributed to the lack of statistical significance. The study had a 46 percent subject loss rate. Thirdly, it would have been more useful to have had subjects who earned approximately the same amount or, at least, did not have the enormous differences in earnings found in this study. Finally, it is suggested that commissions be watched for more than one sales cycle. By incorporating these changes, future studies will have a better chance of determining whether employee fitness affects employee performance or employee satisfaction.