Matching Items (24)

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High-Intensity Exercise Preconditioning Prevents Downregulation of eNOS Expression in the Aorta Following Doxorubicin Treatment

Description

The anthracycline drug Doxorubicin (DOX) is a highly effective treatment for breast cancer, but its clinical utility is limited by dose-dependent cardiovascular toxicity. The toxic effects are partly attributed to

The anthracycline drug Doxorubicin (DOX) is a highly effective treatment for breast cancer, but its clinical utility is limited by dose-dependent cardiovascular toxicity. The toxic effects are partly attributed to DOX-induced generation of reactive oxygen species, which may impair nitric oxide-mediated vasodilation. Exercise training activates antioxidant defense mechanisms and is thus hypothesized to counteract oxidative stress when initiated prior to DOX administration. Adult 8-week old, ovariectomized female Sprague-Dawley rats were divided into 4 groups: sedentary + vehicle (Sed+Veh); Sed+DOX; exercise + veh (Ex+Veh); and Ex+DOX. Rats in the exercise groups were preconditioned with high intensity interval training consisting of 4x4 minute bouts of exercise at 85-95% of VO2peak separated by 2 minutes of active recovery performed 5 days per week. Exercise was implemented one week prior to the first injection and continued throughout the study. Animals received either DOX (4mg/kg) or veh (saline) intraperitoneal injections bi-weekly for a cumulative dose of 12 mg/kg per animal. Five days following the final injection, animals were anesthetized with isoflurane, decapitated and aortas and perivascular adipose tissue (PVAT) were removed for western blot analyses. No significant differences in aortic protein expression were detected for inducible nitric oxide synthase (iNOS) or the upstream activator of endothelial nitric oxide synthase (eNOS), Akt, across groups (p>0.05), whereas eNOS protein expression was significantly downregulated in Sed+DOX (p=0.003). In contrast, eNOS expression was not altered in Ex+DOX treated animals. Protein expression of iNOS in PVAT was upregulated with exercise in the DOX-treated groups (p=0.039). These findings suggest that exercise preconditioning may help mitigate vascular effects of DOX by preventing downregulation of eNOS in the aorta.

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Date Created
  • 2016-12

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Impact of Sleep Restriction on Muscle Recovery Following Eccentric Exercise

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This study was designed with the goal of measuring the effects of sleep deprivation on muscle function. Participants in this study consisted of 19 individuals, 11 of which were in

This study was designed with the goal of measuring the effects of sleep deprivation on muscle function. Participants in this study consisted of 19 individuals, 11 of which were in the restricted group (age 251) and 8 were in the control group (age 231). Measurements of muscle function included isometric strength, isokinetic velocity, and muscle soreness. Isometric strength and isokinetic velocity were taken for knee extension using a dynamometer. Muscle soreness was measured via a 100mm likert visual analogue scale for the step-up and step-down movements with the effected leg. Measurements were taken at baseline, and 48 hours after the damaging bout of eccentric exercise following either 8 hours of sleep per night or 3 hours of sleep per night. Results show that there were no statistical differences between groups for either measurements of isometric strength, isokinetic velocity, or muscle soreness. Due to possible confounding factors, future research needs to be conducted in order to get a better understanding of the effects of sleep deprivation on muscle function.

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  • 2016-12

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WalkIT CoHab: Walking Intervention through Texting Study of Cohabiting Individuals

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With an excessive amount of resources in the United States healthcare system being spent on the treatment of diseases that are largely preventable through lifestyle change, the need for successful

With an excessive amount of resources in the United States healthcare system being spent on the treatment of diseases that are largely preventable through lifestyle change, the need for successful physical activity interventions is apparent. Unfortunately an individual's physical activity and health goals are often not supported by the social context of their daily lives. This single-case design study, Walking Intervention through Text messaging for CoHabiting individuals (WalkIT CoHab), looks at the efficacy of a text based adaptive physical activity intervention to promote walking over a three month period and the effects of social support in intervention performance in three pairs of cohabiting pairs of individuals (n=6). Mean step increase from baseline to intervention ranged from 1300 to 3000 steps per day for all individuals, an average 45.87% increase in physical activity. Goal attainment during the intervention ranged from 43.96% to 71.43%, meaning all participants exceeded the 40% success rate predicted by 60th percentile goals. Social support scores for study partners, unlike social support scores for family and friends, were often in the high social support range and had a moderate increase from pre to post visits for most participants. Although there was variation amongst participants, there was a high correlation in physical activity trends and successful goal attainment in each pair of participants. Less ambitious percentile goals and more personalized motivational text messages might be beneficial to some participants. An extended intervention, something the majority of participants expressed interest in, would further support the efficacy of this behavioral intervention and allow for possible long term benefits of social support in the intervention to be investigated.

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Date Created
  • 2015-05

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The Relationship of Muscle Thickness and Pennation Angle to Muscle Function by Ultrasound Imaging

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This purpose of this study was to develop reliable methods for ultrasound measurements of skeletal muscle architecture, and to identify which specific quadriceps measurements most closely relate to peak isometric

This purpose of this study was to develop reliable methods for ultrasound measurements of skeletal muscle architecture, and to identify which specific quadriceps measurements most closely relate to peak isometric torque of the leg extensors. These data were obtained as part of a larger research study and consist of 9 total subjects (4 males, 5 females; age (30.6 ± 13.6yr). Ultrasound images for muscle thickness and pennation angle were obtained for each subject during two separate testing days (separated by 5-10 days). Images were acquired at various anatomical sites of the quadriceps and each image was analyzed using Image J software. Quadriceps muscles assessed for muscle thickness and pennation angle included the vastus lateralis (VL), and vastus intermedius (VI), while rectus femoris (RF) was assessed only for muscle thickness. Peak isometric torque measurements were obtained at 60 degrees of knee angle for knee extension using an isokinetic dynamometer. Results show that the methods chosen for ultrasound measurement produced reliable inter-day results for muscle thickness and pennation angle. VL muscle thickness and pennation angle obtained at the lateral site corresponding to 39% of leg length was highly related to peak isometric torque for knee extension. The results of this study identify specific measurement sites that are related to muscle function. In addition, these data further validate that ultrasound measurement is reliable to measure muscle thickness and pennation angle in skeletal muscle.

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Date Created
  • 2016-05

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Changes in Glycemia and Serum Lipids Following a 4-Month mHealth Walking Intervention

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Walking interventions focused on increasing step counts are typically associated with salutary effects on glycemia, fasting insulin, insulin resistance and blood lipids which may be in turn associated with improvements

Walking interventions focused on increasing step counts are typically associated with salutary effects on glycemia, fasting insulin, insulin resistance and blood lipids which may be in turn associated with improvements in cardiorespiratory fitness (peak oxygen uptake – VO2peak) and vascular stiffness. We hypothesized that a novel 4-month, behavioral economics-based walking intervention would have favorable effects on glucose homeostasis and blood lipids and that these in turn would be related to VO2peak and vascular stiffness (carotid femoral pulse wave velocity – cfPWV).

We carried out secondary analyses on a subsample of sedentary, overweight/obese adults who participated in a 4-month, 2x2, randomized-controlled walking intervention examining the effects of goal setting (static v. adaptive goals) and rewards (immediate v. delayed) on steps/day (N=96). Fasting blood samples (n=58) were collected from participants before and after the intervention. Premenopausal females were in the follicular phase of their menstrual cycles. Lipid and glucose levels were measured using an automated chemistry analyzer, while insulin was measured using radio-immunoassay. Homeostatic model of insulin resistance (HOMA-IR) was calculated using the following formula (HOMA-IR=glucose x insulin / 405). We examined associations [partial correlations (adjusted for age)] between changes in blood biomarkers and VO2peak and cfPWV, irrespective of group, and we used linear mixed models to examine between-group differences in levels of and change in biomarker outcomes.

Groups did not differ in overall levels of, or degree of change in, biomarker outcomes (all p>0.05). Mean changes, irrespective of group, in biomarkers were as follows: glucose Δ= 0.74± 4.5mg/dl; insulin Δ= 0.09 ± 4.1 µU/ml; total cholesterol Δ= 0.24 ± 20.6 mg/dl; HDL-C Δ= 0.27 ± 5.1 mg/dl; LDL-C Δ= 1.3 ± 19.9 mg/dl; triglycerides Δ= 1.7 ± 27.2 mg/dl; HOMA-IR Δ = -.0548 ± 1.05). We found no significant associations between change in biomarker levels and change in VO2peak or change in cfPWV (all correlation coefficients < 0.15; p > 0.05).

A 4-month, behavioral economics-based mHealth intervention focused on increasing steps/day did not bring about favorable changes on markers of glycemia, insulin resistance and blood lipids.

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  • 2016-05

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Prevalence of Optimal Lifestyle Behaviors in College Undergraduate Students

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Background: Cardiovascular disease (CVD) is the leading cause of mortality in the United States and remains a great public health challenge. Unhealthy lifestyle behaviors (e.g., unhealthy diet, sedentary behavior, cigarette

Background: Cardiovascular disease (CVD) is the leading cause of mortality in the United States and remains a great public health challenge. Unhealthy lifestyle behaviors (e.g., unhealthy diet, sedentary behavior, cigarette smoking, and obesity) are associated with a greater risk of incident CVD and all-cause mortality. From the prevention strategy, maintaining a healthy lifestyle throughout a lifetime is a key to CVD prevention. Nonetheless, the prevalence of healthy lifestyle behaviors in US communities is low as 3 to 5%. Moreover, the prevalence of a healthy population among college students remains unknown. Objective: We investigated the prevalence of healthy lifestyle behaviors among college students. Methods: We recruited 747 undergraduate students from Arizona State University using a survey questionnaire. The survey questionnaire investigated demographic characteristics, body mass index, dietary habits, physical activity habits, and smoking habits. The chi-square test was used to investigate the frequency of ideal lifestyle behaviors in college students. Results: Prevalence of students who met all 4 ideal health behaviors (ideal cardiovascular health) is very low at 7.6%. Approximately 55.7% of students had only 2 or less ideal lifestyle behaviors (poor cardiovascular health). In addition, there were no statistical differences in combined ideal lifestyle behaviors across gender and different years of undergraduate studies. Conclusion: College students had a very low prevalence of healthy lifestyle behaviors. Increasing healthy low-risk students throughout college education is an important strategy to prevent chronic disease morbidity and mortality at individual and population level.

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Date Created
  • 2015-05

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Combined Impact of Aerobic Exercise and Music on Glycemic Control and Anxiety Symptoms in Type 2 Diabetic and Non-Diabetic Men and Women

Description

ABSTRACT
Background: Although aerobic exercise has been shown to improve the glycemic control of individuals with type 2 diabetes, a simple and effective approach to manage post-meal glycemic control remains

ABSTRACT
Background: Although aerobic exercise has been shown to improve the glycemic control of individuals with type 2 diabetes, a simple and effective approach to manage post-meal glycemic control remains less clear.
Purpose: This study examined the effect of 15-minute of post-meal aerobic exercise on the glycemic control and anxiety scores as compared with control trials in participants with and without type 2 diabetes.
Methods: Six adults volunteered to participate in the study (3 adults with type 2 diabetes, age = 44.33 ± 7.71; and 3 adults without type 2 diabetes, age = 31.67 ± 15.76). All participants received aerobic exercise intervention and control treatments. The aerobic exercise treatment was listening to upbeat music and dancing for 15-minutes, whereas the control participants ingested 1 gram of vitamin C 30-minutes post-meal. Glucose levels were measured at baseline, and the 10, and 15-minute mark in both exercise intervention and control conditions 30-minutes post-meal.
Results: There was a significant interaction between treatment and time on the change in glucose levels (P<0.001). There was a significant mean difference in change in glucose levels between exercise intervention and control conditions (P = 0.002). Change in glucose levels in exercise intervention was significantly decreased at 10-minute (-18 ± 4.35 vs. 1.67 ± 4.34, P = 0.009) and 15-minute (-24 ± 4.88 vs. 5.67 ± 4.88, P = 0.001) compared with control condition. Although there were no statistical differences in state anxiety scores between pre- and post-exercise intervention (p=0.42), there was a significant trend in the reduction of state anxiety scores in diabetic participants, as compared with healthy participants, after 15-minute exercise intervention (-8 vs. -1).
Conclusion: Aerobic exercise for 15-minute by dancing to music after a meal is an effective approach to controlling the blood glucose levels in type 2 diabetic and healthy persons.

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Date Created
  • 2015-05

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Doxorubicin Induced Cardiotoxicity and High Intensity Aerobic Exercise

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Doxorubicin (DOX) is a cardiotoxic, anthracycline-based, anti-neoplastic agent that causes pathological cardiac remodeling due to altered protein expression associated with cardiotoxicity. DOX cardiotoxicity causes increased Akt phosphorylation, blunted AMPK phosphorylation

Doxorubicin (DOX) is a cardiotoxic, anthracycline-based, anti-neoplastic agent that causes pathological cardiac remodeling due to altered protein expression associated with cardiotoxicity. DOX cardiotoxicity causes increased Akt phosphorylation, blunted AMPK phosphorylation and upregulated mTOR phosphorylation. Akt is activated by cellular stress and damage. AMPK is activated by increases in AMP and ADP concentrations and decreased ATP concentration. mTOR is active in cellular growth and remodeling. These proteins are cellular kinases with cascades that are influenced by one another. Exercise preconditioning may diminish the cardiotoxic effects on these proteins. Female, Ovariectomized Sprague-Dawley rats (N=33) were randomized to: Exercise+DOX (EX+DOX, n=9); Exercise+Vehicle (EX+VEH, n=8); Sedentary+DOX (SED+DOX, n=8); and Sedentary+Vehicle (SED+VEH, n=8) groups. DOX (4mg/kg) or VEH (saline) intraperitoneal injections were administered bi-weekly (cumulative dose of 12mg/kg). VEH animals received body weight matched volumes of saline based on dosing in animals receiving DOX. Exercise (EX) animals underwent high intensity (85-95% VO2 peak) interval training (HIIT) (4x4 min bouts) separated by low intensity (50-60% VO2max) intervals (2 min bouts) 5 days per week. Exercise began 1 week prior to the first injection and was continued throughout the study. Rats were euthanized 5 days after the last injection. Left ventricular tissue was isolated, processed into lysate and used for western blot analyses [2x2 ANOVA; (α=0.05)]. DOX induced significant phosphorylation of Akt and mTOR (p=0.035; p=0.032) only in SED+DOX rats, but unchanged in EX+DOX rats. No significant differences (p=0.374) in AMPK phosphorylation were observed between groups. Exercise Preconditioning prevents some DOX-induced changes in the cardiac mTOR signaling pathway implicated in pathological remodeling.

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Date Created
  • 2017-05

Adaptive Goal Setting and Financial Incentives: A 2 × 2 Factorial Randomized Controlled Trial to Increase Adults’ Physical Activity

Description

Background: Emerging interventions that rely on and harness variability in behavior to adapt to individual performance over time may outperform interventions that prescribe static goals (e.g., 10,000 steps/day). The purpose

Background: Emerging interventions that rely on and harness variability in behavior to adapt to individual performance over time may outperform interventions that prescribe static goals (e.g., 10,000 steps/day). The purpose of this factorial trial was to compare adaptive vs. static goal setting and immediate vs. delayed, non-contingent financial rewards for increasing free-living physical activity (PA).

Methods: A 4-month 2 × 2 factorial randomized controlled trial tested main effects for goal setting (adaptive vs. static goals) and rewards (immediate vs. delayed) and interactions between factors to increase steps/day as measured by a Fitbit Zip. Moderate-to-vigorous PA (MVPA) minutes/day was examined as a secondary outcome.

Results: Participants (N = 96) were mainly female (77%), aged 41 ± 9.5 years, and all were insufficiently active and overweight/obese (mean BMI = 34.1 ± 6.2). Participants across all groups increased by 2389 steps/day on average from baseline to intervention phase (p < .001). Participants receiving static goals showed a stronger increase in steps per day from baseline phase to intervention phase (2630 steps/day) than those receiving adaptive goals (2149 steps/day; difference = 482 steps/day, p = .095). Participants receiving immediate rewards showed stronger improvement (2762 step/day increase) from baseline to intervention phase than those receiving delayed rewards (2016 steps/day increase; difference = 746 steps/day, p = .009). However, the adaptive goals group showed a slower decrease in steps/day from the beginning of the intervention phase to the end of the intervention phase (i.e. less than half the rate) compared to the static goals group (−7.7 steps vs. -18.3 steps each day; difference = 10.7 steps/day, p < .001) resulting in better improvements for the adaptive goals group by study end. Rate of change over the intervention phase did not differ between reward groups. Significant goal phase x goal setting x reward interactions were observed.

Conclusions: Adaptive goals outperformed static goals (i.e., 10,000 steps) over a 4-month period. Small immediate rewards outperformed larger, delayed rewards. Adaptive goals with either immediate or delayed rewards should be preferred for promoting PA.

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Date Created
  • 2017-03-29

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The Effect of Exercise Training on Biventricular Myocardial Strain in Heart Failure With Preserved Ejection Fraction

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Aims: High-intensity interval training (HIIT) improves peak oxygen uptake and left ventricular diastology in patients with heart failure with preserved ejection fraction (HFpEF). However, its effects on myocardial strain in

Aims: High-intensity interval training (HIIT) improves peak oxygen uptake and left ventricular diastology in patients with heart failure with preserved ejection fraction (HFpEF). However, its effects on myocardial strain in HFpEF remain unknown. We explored the effects of HIIT and moderate-intensity aerobic continuous training (MI-ACT) on left and right ventricular strain parameters in patients with HFpEF. Furthermore, we explored their relationship with peak oxygen uptake (VO2peak).

Methods and Results: Fifteen patients with HFpEF (age = 70 ± 8.3 years) were randomized to either: (i) HIIT (4 × 4 min, 85–90% peak heart rate, interspersed with 3 min of active recovery; n = 9) or (ii) MI-ACT (30 min at 70% peak heart rate; n = 6). Patients were trained 3 days/week for 4 weeks and underwent VO2peak testing and 2D echocardiography at baseline and after completion of the 12 sessions of supervised exercise training. Left ventricular (LV) and right ventricular (RV) average global peak systolic longitudinal strain (GLS) and peak systolic longitudinal strain rate (GSR) were quantified. Paired t-tests were used to examine within-group differences and unpaired t-tests used for between-group differences (α = 0.05). Right ventricular average global peak systolic longitudinal strain improved significantly in the HIIT group after training (pre = −18.4 ± 3.2%, post = −21.4 ± 1.7%; P = 0.02) while RV-GSR, LV-GLS, and LV-GSR did not (P > 0.2). No significant improvements were observed following MI-ACT. No significant between-group differences were observed for any strain measure. ΔLV-GLS and ΔRV-GLS were modestly correlated with ΔVO2peak (r = −0.48 and r = −0.45; P = 0.1, respectively).

Conclusions: In patients with HFpEF, 4 weeks of HIIT significantly improved RV-GLS.

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Created

Date Created
  • 2017-03-16