Matching Items (21)

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Accuracy of Neck Circumference in Classifying Overweight and Obese US Children

Description

Objective. To evaluate classification accuracy of NC and compare it with body mass index (BMI) in identifying overweight/obese US children. Methods. Data were collected from 92 children (boys: 61) aged

Objective. To evaluate classification accuracy of NC and compare it with body mass index (BMI) in identifying overweight/obese US children. Methods. Data were collected from 92 children (boys: 61) aged 7 to 13 over a 2-year period. NC, BMI, and percent of body fat (BF%) were measured in each child and their corresponding cut-off values were applied to classify the children as being overweight/obese. Classification accuracy of NC and BMI was systematically investigated for boys and girls in relation to true overweight/obesity categorization as assessed with a criterion measure of BF% (i.e., Bod Pod). Results. For boys, Cohen’s k (0.25), sensitivity (38.1%), and specificity (85.0%) of NC were smaller in comparison with Cohen’s k (0.57), sensitivity (57.1%), and specificity (95.0%) of BMI in relation to BF% categorization. For girls, Cohen’s k (0.45), sensitivity (50.0%), and specificity (91.3%) of NC were smaller in comparison with Cohen’s k (0.52), sensitivity (50.0%), and specificity (95.7%) of BMI. Conclusion. NC measurement was not better than BMI in classifying childhood overweight/obesity and, for boys, NC was inferior to BMI. Pediatricians and/or pediatric researchers should be cautious or wary about incorporating NC measurements in their pediatric care and/or research.

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Date Created
  • 2014-01-30

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

Description

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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Date Created
  • 2016-05

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The effects of high-intensity interval exercise on postprandial fat and carbohydrate oxidation in healthy adults

Description

The purpose of this study was to investigate the effects of high intensity interval exercise (HIIE) on postprandial fat and carbohydrate oxidation after a high carbohydrate and fat meal in

The purpose of this study was to investigate the effects of high intensity interval exercise (HIIE) on postprandial fat and carbohydrate oxidation after a high carbohydrate and fat meal in healthy adults. It was hypothesized that the HIIE would result in greater postprandial fat oxidation than the control condition. Three subjects, all non-obese (BMI<30) from the ages of 21-24, underwent a 3 visit protocol. The first visit was to establish a VO2 max (on a cycle ergometer) and the following two were randomized between a control and exercise condition. The exercise condition was comprised of one hour rest to provide baseline data, followed by a 1 minute on (90-95% HR max), one minute off high intensity interval protocol on a cycle ergometer. This was conducted until the same amount of kcal as the standard meal (490 kcal. 250 kcal snickers and 240 kcal sprite) was expended. After the exercise, the participant waited for one hour to minimize the effects of the excess post-exercise oxygen consumption (EPOC) period, and then consumed the meal. Once this was completed, VO2 was measured for the last 10 minutes of every 30 minutes for a full 5 hours postprandial. The same methodology was employed in the control condition except for the exercise protocol. Results showed a significantly greater fat oxidation in the HIIE condition, oxidizing 28 grams, 32 grams, and 27 grams of fat in each of the 3 subjects compared to 14, 16, and 17 grams in the control condition respectively. This supports the notion that HIIE results in greater postprandial fat oxidation compared to seated rest.

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Date Created
  • 2018-05

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Validity and reliability of Nike + Fuelband for estimating physical activity energy expenditure

Description

Background
The Nike + Fuelband is a commercially available, wrist-worn accelerometer used to track physical activity energy expenditure (PAEE) during exercise. However, validation studies assessing the accuracy of this device for estimating

Background
The Nike + Fuelband is a commercially available, wrist-worn accelerometer used to track physical activity energy expenditure (PAEE) during exercise. However, validation studies assessing the accuracy of this device for estimating PAEE are lacking. Therefore, this study examined the validity and reliability of the Nike + Fuelband for estimating PAEE during physical activity in young adults. Secondarily, we compared PAEE estimation of the Nike + Fuelband with the previously validated SenseWear Armband (SWA).
Methods
Twenty-four participants (n = 24) completed two, 60-min semi-structured routines consisting of sedentary/light-intensity, moderate-intensity, and vigorous-intensity physical activity. Participants wore a Nike + Fuelband and SWA, while oxygen uptake was measured continuously with an Oxycon Mobile (OM) metabolic measurement system (criterion).
Results
The Nike + Fuelband (ICC = 0.77) and SWA (ICC = 0.61) both demonstrated moderate to good validity. PAEE estimates provided by the Nike + Fuelband (246 ± 67 kcal) and SWA (238 ± 57 kcal) were not statistically different than OM (243 ± 67 kcal). Both devices also displayed similar mean absolute percent errors for PAEE estimates (Nike + Fuelband = 16 ± 13 %; SWA = 18 ± 18 %). Test-retest reliability for PAEE indicated good stability for Nike + Fuelband (ICC = 0.96) and SWA (ICC = 0.90).
Conclusion
The Nike + Fuelband provided valid and reliable estimates of PAEE, that are similar to the previously validated SWA, during a routine that included approximately equal amounts of sedentary/light-, moderate- and vigorous-intensity physical activity.

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Created

Date Created
  • 2015-06-30

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Examination of Different Accelerometer Cut-Points for Assessing Sedentary Behaviors in Children

Description

Background
Public health research on sedentary behavior (SB) in youth has heavily relied on accelerometers. However, it has been limited by the lack of consensus on the most accurate accelerometer

Background
Public health research on sedentary behavior (SB) in youth has heavily relied on accelerometers. However, it has been limited by the lack of consensus on the most accurate accelerometer cut-points as well as by unknown effects caused by accelerometer position (wrist vs. hip) and output (single axis vs. multiple axes). The present study systematically evaluates classification accuracy of different Actigraph cut-points for classifying SB using hip and wrist-worn monitors and establishes new cut-points to enable use of the 3-dimensional vector magnitude data (for both hip and wrist placement).
Methods
A total of 125 children ages 7–13 yrs performed 12 randomly selected activities (from a set of 24 different activities) for 5 min each while wearing tri-axial Actigraph accelerometers on both the hip and wrist. The accelerometer data were categorized as either sedentary or non-sedentary minutes using six previously studied cut-points: 100counts-per-minute (CPM), 200CPM, 300CPM, 500CPM, 800CPM and 1100CPM. Classification accuracy was evaluated with Cohen's Kappa (κ) and new cut-points were identified from Receiver Operating Characteristic (ROC).
Results
Of the six cut-points, the 100CPM value yielded the highest classification accuracy (κ = 0.81) for hip placement. For wrist placement, all of the cut-points produced low classification accuracy (ranges of κ from 0.44 to 0.67). Optimal sedentary cut-points derived from ROC were 554.3CPM (ROC-AUC of 0.99) for vector magnitude for hip, 1756CPM (ROC-AUC of 0.94) for vertical axis for wrist, and 3958.3CPM (ROC-AUC of 0.93) for vector magnitude for wrist placement.
Conclusions
The 100CPM was supported for use with vertical axis for hip placement, but not for wrist placement. The ROC-derived cut-points can be used to classify youth SB with the wrist and with vector magnitude data.

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Agent

Created

Date Created
  • 2014-04-03

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Physiological Effects of High Intensity Interval Training on Women with Breast Cancer Undergoing Anthracycline-based Chemotherapy

Description

Estimates indicate that in the United States 1 in 8 women will develop breast cancer in their lifetime. Improved cancer screenings, early detection, and targeted treatments have increased breast cancer

Estimates indicate that in the United States 1 in 8 women will develop breast cancer in their lifetime. Improved cancer screenings, early detection, and targeted treatments have increased breast cancer survival rates. However, breast cancer patients treated with chemotherapy are at an increased risk for cardiovascular disease, functional impairments, and loss of cardiorespiratory fitness. These negative outcomes have implications for early morbidity and mortality. The purpose of this thesis was to test the hypothesis that high-intensity exercise preconditioning (exercise commenced prior to initiating chemotherapy and continued throughout treatment cycles) preserves health-related outcomes in breast cancer patients treated with anthracycline-containing chemotherapy. Here, we present a subset of preliminary data from an ongoing trial (NCT02842658) that is focused on VO2peak and skeletal muscle outcomes from the first 10 participants that have enrolled in the trial. Breast cancer patients (N=10; 50 ± 11 y; 168 ± 4 cm; 92 ± 37 kg; 32.3 ± 12.3 kg/m2) scheduled to receive anthracycline-containing chemotherapy were randomly assigned to one of two interventions: 1) exercise preconditioning, (3 days per week of supervised exercise throughout treatment) or 2) standard of care (attention-control). Pre-testing occurred 1-2 week prior to chemotherapy. The interventions were initiated 1 week prior to chemotherapy and continued throughout anthracycline treatment. Post-testing occurred 3-7 days following the last anthracycline treatment. VO2peak (L/min) was reduced by 16% in the control group (P < 0.05), whereas VO2peak was preserved in the exercise preconditioning group. Trends for greater preservation and/or improvement in the exercise preconditioning group were also observed for lean body mass and peak heart rate. Hand grip strength was not changed in either group (P > 0.05). Both groups demonstrated an increase in ultrasound-derived echogenicity measures of the vastus lateralis (P < 0.05), indicating changes in the composition of the skeletal muscle during treatment. These preliminary data highlight that exercise preconditioning may serve as a strategy to preserve cardiorespiratory fitness and perhaps lean mass during anthracycline treatment of breast cancer. There remains a need for larger, definitive clinical trials to identify strategies to prevent the array of chemotherapy-induced toxicities that are observed in breast cancer patients treated with anthracyclines.

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Created

Date Created
  • 2020-05

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Acute affects [i.e. effects] of a walking workstation on ambulatory blood pressure in prehypertensive adults

Description

INTRODUCTION: Exercise performed at moderate to vigorous intensities has been shown to generate a post exercise hypotensive response. Whether this response is observed with very low exercise intensities is unclear.

INTRODUCTION: Exercise performed at moderate to vigorous intensities has been shown to generate a post exercise hypotensive response. Whether this response is observed with very low exercise intensities is unclear. PURPOSE: To compare post physical activity ambulatory blood pressure (ABP) response to a single worksite walking day and a normal sedentary work day in pre-hypertensive adults. METHODS: Participants were 7 pre-hypertensive (127 + 8 mmHg / 83 + 8 mmHg) adults (3 male, 4 female, age = 42 + 12 yr) who participated in a randomized, cross-over study that included a control and a walking treatment. Only those who indicated regularly sitting at least 8 hours/day and no structured physical activity were enrolled. Treatment days were randomly assigned and were performed one week apart. Walking treatment consisted of periodically increasing walk time up to 2.5 hours over the course of an 8 hour work day on a walking workstation (Steelcase Company, Grand Rapids, MI). Walk speed was set at 1 mph. Participants wore an ambulatory blood pressure cuff (Oscar 2, SunTech Medical, Morrisville, NC) for 24-hours on both treatment days. Participants maintained normal daily activities on the control day. ABP data collected from 9:00 am until 10:00 pm of the same day were included in statistical analyses. Linear mixed models were used to detect differences in systolic (SBP) and diastolic blood pressure (DBP) by treatment condition over the whole day and post workday for the time periods between 4 -10 pm when participants were no longer at work. RESULTS:BP was significantly lower in response to the walking treatment compared to the control day (Mean SBP 126 +7 mmHg vs.124 +7 mmHg, p=.043; DBP 80 + 3 mmHg vs. 77 + 3 mmHg, p = 0.001 respectively). Post workday (4:00 to 10:00 pm) SBP decreased 3 mmHg (p=.017) and DBP decreased 4 mmHg (p<.001) following walking. CONCLUSION: Even low intensity exercise such as walking on a walking workstation is effective for significantly reducing acute BP when compared to a normal work day.

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Agent

Created

Date Created
  • 2013

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The Effect of Resistance Training on Arterial Stiffness and Central Hemodynamics

Description

Cardiovascular disease has long been one of the leading causes of morbidity in the world and places a large burden on the health care system. Exercise has been shown to

Cardiovascular disease has long been one of the leading causes of morbidity in the world and places a large burden on the health care system. Exercise has been shown to reduce the risk of developing cardiovascular disease and the risk factors associated with it. Much of the focus of research has been on aerobic exercise modalities and their effect on these risk factors, and less is known in regard to the effect of resistance training. One novel risk factor for cardiovascular disease is arterial stiffness, specifically aortic stiffness. Aortic stiffness can be measured by carotid-femoral pulse wave velocity (PWV) and central pressure characteristics such as central blood pressures and augmentation index. The objective of this study was to assess the effect that two different 12-week long resistance training interventions would have on these measurements in sedentary, overweight and obese men and women (BMI ≥ 25 kg/m2). Twenty-one subjects completed the study and were randomized into one of the following groups: control, a low repetition/high load (LRHL) group which performed 3 sets of 5 repetitions for all exercises, and a high repetition/low load (HRLL) group which performed 3 sets of 15 repetitions for all exercises. Those in the resistance training groups performed full-body exercise routines on 3 nonconsecutive days of the week. Changes in arterial stiffness, central blood pressures, and brachial blood pressures were measured before and after the 12-week intervention period. PWV showed significant group by time interaction (p= 0.024) but upon post hoc testing no significant differences were observed due to the control group confounding (control: 7.6 ± 0.8 vs. 7.1 ± 0.8, LRHL: 6.7 ± 0.5 vs. 6.9 ± 0.5, HRLL: 7.03 ± 0.67 vs. 6.59). No other significant interactions or differences were observed for any of the variables tested. Based on the results of this study a 12-week long resistance intervention training, neither high nor moderate-intensity resistance training, resulted in improvements in indices of vascular stiffness or central and peripheral blood pressures.

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Agent

Created

Date Created
  • 2020

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The assessment of physical activity and sedentary behaviors

Description

The health benefits of physical activity are widely accepted. Emerging research also indicates that sedentary behaviors can carry negative health consequences regardless of physical activity level. This dissertation explored four

The health benefits of physical activity are widely accepted. Emerging research also indicates that sedentary behaviors can carry negative health consequences regardless of physical activity level. This dissertation explored four projects that examined measurement properties of physical activity and sedentary behavior monitors. Project one identified the oxygen costs of four other care activities in seventeen adults. Pushing a wheelchair and pushing a stroller were identified as moderate-intensity activities. Minutes spent engaged in these activities contribute towards meeting the 2008 Physical Activity Guidelines. Project two identified the oxygen costs of common cleaning activities in sixteen adults. Mopping a floor was identified as moderate-intensity physical activity, while cleaning a kitchen and cleaning a bathtub were identified as light-intensity physical activity. Minutes spent engaged in mopping a floor contributes towards meeting the 2008 Physical Activity Guidelines. Project three evaluated the differences in number of minutes spent in activity levels when utilizing different epoch lengths in accelerometry. A shorter epoch length (1-second, 5-seconds) accumulated significantly more minutes of sedentary behaviors than a longer epoch length (60-seconds). The longer epoch length also identified significantly more time engaged in light-intensity activities than the shorter epoch lengths. Future research needs to account for epoch length selection when conducting physical activity and sedentary behavior assessment. Project four investigated the accuracy of four activity monitors in assessing activities that were either sedentary behaviors or light-intensity physical activities. The ActiGraph GT3X+ assessed the activities least accurately, while the SenseWear Armband and ActivPAL assessed activities equally accurately. The monitor used to assess physical activity and sedentary behaviors may influence the accuracy of the measurement of a construct.

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Agent

Created

Date Created
  • 2012

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Potential therapeutic benefits of flaxseeds in the treatment of type 2 diabetes symptoms

Description

Background: Despite the reported improvements in glucose regulation associated with flaxseeds (Linum usitatissimum) few clinical trials have been conducted in diabetic participants. Objective: To evaluate the efficacy of ground flaxseed

Background: Despite the reported improvements in glucose regulation associated with flaxseeds (Linum usitatissimum) few clinical trials have been conducted in diabetic participants. Objective: To evaluate the efficacy of ground flaxseed consumption at attenuating hyperglycemia, dyslipidemia, inflammation, and oxidative stress as compared to a control in adults with non-insulin dependent type 2 diabetes (T2D). Design: In a randomized parallel arm controlled efficacy trial, participants were asked to consume either 28 g/d ground flaxseed or the fiber-matched control (9 g/d ground psyllium husk) for 8 weeks. The study included 17 adults (9 male, 8 females; 46±14 y; BMI: 31.4±5.7 kg/m2) with a diagnosis of T2D ≥ 6 months. Main outcomes measured included: glycemic control (HbA1c, fasting plasma glucose, fasting serum insulin, and HOMA-IR), lipid profile (total cholesterol, LDL-C, HDL-C, total triglycerides, and calculated VLDL-C), markers of inflammation and oxidative stress (TNF-alpha, TBARS, and NOx), and dietary intake (energy, total fat, total fiber, sodium). Absolute net change for measured variables (week 8 values minus baseline values) were compared using Mann-Whitney U non-parametric tests, significance was determined at p ≤ 0.05. Results: There were no significant changes between groups from baseline to week 8 in any outcome measure of nutrient intake, body composition, glucose control, or lipid concentrations. There was a modest decrease in TNF-alpha in the flaxseed group as compared to the control (p = 0.06) as well as a mild decrease in TBARS in the flaxseed as compared to the control group (p = 0.083), though neither were significant. Conclusions: The current study did not detect a measurable association between 28 g/d flaxseed consumption for 8 weeks in T2D participants and improvements in glycemic control or lipid profiles. There was a modest, albeit insignificant, decrease in markers of inflammation and oxidative stress in the flaxseed group as compared to the control, which warrants further study.

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Agent

Created

Date Created
  • 2015