Publications by authors named "Chantal Vella"

35 Publications

Perceived Risk and Intentions to Practice Health Protective Behaviors in a Mining-Impacted Region.

Int J Environ Res Public Health 2020 10 28;17(21). Epub 2020 Oct 28.

Department of Natural Resources and Society, University of Idaho, Moscow, ID 83844, USA.

Effective risk communication strategies are critical to reducing lead exposure in mining-impacted communities. Understanding the strength of the associations between perceived risk and individuals' behavioral intentions to protect their health is important for developing these strategies. We conducted a survey within three communities of northern Idaho, USA ( = 306) in or near a Superfund Megasite with legacy mining contamination. Survey data were used to test a theoretical model based on the Health Belief Model. Respondents had higher intentions to practice health protective behaviors when they perceived the risk of lead contamination as severe and recognized the benefits of practicing health protective behaviors. Women reported higher behavioral intentions than men, but age and mining affiliation were not significantly associated with behavioral intentions. Although managing lead hazards in communities impacted by mining is challenging due to widely distributed contamination, effective health risk messages, paired with remediation, are powerful tools to protect the health and safety of residents.
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http://dx.doi.org/10.3390/ijerph17217916DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7672644PMC
October 2020

The first wave of COVID-19 in Malta; a national cross-sectional study.

PLoS One 2020 15;15(10):e0239389. Epub 2020 Oct 15.

Department of Infectious Diseases, Mater Dei Hospital, Msida, Malta.

Introduction: The COVID-19 pandemic has posed major challenges to all aspects of healthcare. Malta's population density, large proportion of elderly and high prevalence of diabetes and obesity put the country at risk of uncontrolled viral transmission and high mortality. Despite this, Malta achieved low mortality rates compared to figures overseas. The aim of this paper is to identify key factors that contributed to these favorable outcomes.

Methods: This is a retrospective, observational, nationwide study which evaluates outcomes of patients during the first wave of the pandemic in Malta, from the 7th of March to the 24th of April 2020. Data was collected on demographics and mode of transmission. Hospitalization rates to Malta's main general hospital, Mater Dei Hospital, length of in-hospital stay, intensive care unit admissions and 30-day mortality were also analyzed.

Results: There were 447 confirmed cases in total; 19.5% imported, 74.2% related to community transmission and 6.3% nosocomially transmitted. Ninety-three patients (20.8%) were hospitalized, of which 4 were children. Patients with moderate-severe disease received hydroxychloroquine and azithromycin, in line with evidence available at the time. A total of 4 deaths were recorded, resulting in an all-cause mortality of 0.89%. Importantly, all admitted patients with moderate-severe disease survived to 30-day follow up.

Conclusion: Effective public health interventions, widespread testing, remote surveillance of patients in the community and a low threshold for admission are likely to have contributed to these favorable outcomes. Hospital infection control measures were key in preventing significant nosocomial spread. These concepts can potentially be applied to stem future outbreaks of viral diseases. Patients with moderate-severe disease had excellent outcomes with no deaths reported at 30-day follow up.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0239389PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7561161PMC
October 2020

Muscle area and density and risk of all-cause mortality: The Multi-Ethnic Study of Atherosclerosis.

Metabolism 2020 10 23;111:154321. Epub 2020 Jul 23.

Department of Family Medicine and Public Health, University of California, San Diego, San Diego, CA, United States of America.

Background: Lean muscle plays critical roles in physical functioning and metabolism. However, little is known regarding associations between muscle and mortality in adults.

Objective: The purpose was to evaluate associations between abdominal muscle quantity (area) and quality (density) with risk of all-cause mortality in a diverse cohort free of cardiovascular disease.

Design: Data were taken from the Abdominal Body Composition, Inflammation, and Cardiovascular Disease ancillary study of the Multi-Ethnic Study of Atherosclerosis prospective cohort study. Participants were adults (45-85 years) free of extant cardiovascular disease, and of Hispanic, African American, Chinese, or Caucasian descent. Of the original 6814 MESA participants, a random, representative sample (n = 1974) participated in the ancillary body composition study. Abdominal muscle area and density were measured from computed tomography scans spanning L2-L4. Muscle density was measured as attenuation in Hounsfield units, and area was quantified as cm. Gender-stratified cox proportional hazard models assessed the risk of all-cause mortality across gender-specific quartiles of muscle area and density adjusting for confounders, with area and density entered simultaneously.

Results: At baseline, the mean age for men (n = 946) and women (n = 955) was 61.5 and 62.5 years and median follow-up time was 10.6 and 10.9 years, respectively. Muscle density was inversely associated with mortality, with the highest quartile of density showing a 73% reduction in risk for men (HR = 0.27, 95% CI = 0.14-0.51; p-trend<0.001) and 57% reduction for women (HR = 0.43, 95% CI = 0.18-1.01; p-trend = 0.04) compared to the lowest quartile when adjusting for mortality risk factors, lifestyle, BMI and visceral fat. There was no association between muscle area and all-cause mortality for men (p-trend = 0.58) or women (p-trend = 0.47).

Conclusions: Greater abdominal muscle density, but not muscle area, is associated with markedly lower risk of all-cause mortality across a decade of follow up. Muscle quality may be a powerful predictor of mortality in community dwelling adults.
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http://dx.doi.org/10.1016/j.metabol.2020.154321DOI Listing
October 2020

Associations of leisure screen time with cardiometabolic biomarkers in college-aged adults.

J Behav Med 2020 12 26;43(6):1014-1025. Epub 2020 May 26.

Department of Movement Sciences, University of Idaho, Moscow, ID, USA.

We examined whether screen time was associated with cardiometabolic disease (CMD) risk factors in young adults. Ninety-five adults (19.9 ± 11.4 years) self-reported medical and health behavior history, screen time (television viewing, video games and computer games), and dietary intake. Waist circumference, blood pressure, fasting glucose and lipid levels, cardiorespiratory fitness (VOpeak), and body composition were measured. Total sedentary behavior and moderate-to-vigorous physical activity (MVPA) were measured by accelerometer. On average, leisure screen time (2.0 ± 1.6 h day) accounted for 24% of total sedentary time (8.4 ± 1.5 h day). After adjustment for demographics, smoking, sleep duration, total energy intake, total sedentary time and MVPA, a 1-standard deviation increase in leisure screen time was associated with a 26% higher BMI, 29% higher waist circumference, 25% higher fat mass, 23% higher triglyceride, and 24% lower VOpeak (p < 0.05). Our findings suggest that screen time may contribute to the risk of obesity and CMD in young adults.
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http://dx.doi.org/10.1007/s10865-020-00161-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7677220PMC
December 2020

Skeletal muscle area and density are associated with lipid and lipoprotein cholesterol levels: The Multi-Ethnic Study of Atherosclerosis.

J Clin Lipidol 2020 Jan - Feb;14(1):143-153. Epub 2020 Jan 13.

Department of Family Medicine and Public Health, School of Medicine, University of California San Diego, La Jolla, CA, USA.

Background: Loss of muscle mass with age may be a key player in metabolic dysregulation. We examined the associations between abdominal muscle area and density with lipids and lipoproteins.

Methods: One thousand eight hundred and sixty eight adults completed health history and physical activity questionnaires, provided venous blood samples for lipids and inflammatory biomarkers, and underwent computed tomography to quantify body composition. Associations between muscle area and density with multiple lipid measures were assessed with multivariable linear and logistic regression.

Results: The mean age and body mass index of participants was 65 years and 28 kg/m, respectively, and 50% were female. After adjustment for demographics, cardiovascular disease risk factors, lipid-lowering medications, physical activity, sedentary behavior, inflammatory biomarkers, and central obesity, a 1-standard deviation increase in total abdominal, stability, and locomotor muscle areas was associated with a 13%, 11%, and 8% lower high-density lipoprotein cholesterol level, respectively (P < .05). With similar adjustment, a 1-standard deviation increase in total abdominal and stability muscle area was associated with a 13% and 12% lower total cholesterol level, respectively (P < .01). Compared to the lowest quartiles of total, stability, and locomotor muscle area, those in the higher quartiles of muscle area had over a 40% reduction in the odds of triglyceride levels greater than 150 mg/dL (P < .05). Total abdominal muscle density was positively associated with total cholesterol (P < .05) but was not associated with the other lipid outcomes.

Conclusion: Maintaining adequate skeletal muscle mass with age may decrease specific lipid levels related to hyperlipidemia and development of cardiometabolic disease.
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http://dx.doi.org/10.1016/j.jacl.2020.01.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7085431PMC
January 2020

Comparison of Self-Reported and Objectively Measured Sedentary Behavior and Physical Activity in Undergraduate Students.

Meas Phys Educ Exerc Sci 2019 7;23(3):237-248. Epub 2019 May 7.

University of Idaho, Department of Movement Sciences, Exercise Physiology Research Laboratory, Moscow, ID.

Objective: To investigate differences between estimates of sedentary behavior and physical activity (PA) from the International Physical Activity Questionnaire (IPAQ) and accelerometry in undergraduate students.

Participants: 91 students participated in the study.

Methods: Sedentary behavior and PA were objectively measured by an accelerometer for 7 days and then self-reported with the IPAQ. Partial correlations were used to assess associations among PA variables and participant characteristics between the methods. Agreement was assessed via the Bland-Altman method.

Results: Correlation coefficients between self-reported and objectively measured PA ranged from 0.21 to 0.38 (≤0.05 for all). A higher proportion of students were classified as meeting PA guidelines via self-report compared to objective measurements. Bland-Altman plots revealed acceptable agreement between methods, however, bias was evident for all PA intensities. Sex and lean body mass impacted these differences.

Conclusions: Researchers should exercise caution when interpreting PA assessed via the IPAQ in undergraduate students.
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http://dx.doi.org/10.1080/1091367X.2019.1610765DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6941744PMC
May 2019

Regulation of metabolism during hibernation in brown bears (Ursus arctos): Involvement of cortisol, PGC-1α and AMPK in adipose tissue and skeletal muscle.

Comp Biochem Physiol A Mol Integr Physiol 2020 02 25;240:110591. Epub 2019 Oct 25.

Department of Biological Sciences, Dana and David Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, CA 90089, USA. Electronic address:

The purpose of this study was to investigate changes in expression of known cellular regulators of metabolism during hyperphagia (Sept) and hibernation (Jan) in skeletal muscle and adipose tissue of brown bears and determine whether signaling molecules and transcription factors known to respond to changes in cellular energy state are involved in the regulation of these metabolic adaptations. During hibernation, serum levels of cortisol, glycerol, and triglycerides were elevated, and protein expression and activation of AMPK in skeletal muscle and adipose tissue were reduced. mRNA expression of the co-activator PGC-1α was reduced in all tissues in hibernation whereas mRNA expression of the transcription factor PPAR-α was reduced in the vastus lateralis muscle and adipose tissue only. During hibernation, gene expression of ATGL and CD36 was not altered; however, HSL gene expression was reduced in adipose tissue. During hibernation gene expression of the lipogenic enzyme DGAT in all tissues and the expression of the FA oxidative enzyme LCAD in the vastus lateralis muscle were reduced. Gene and protein expression of the glucose transporter GLUT4 was decreased in adipose tissue in hibernation. Our data suggest that high cortisol levels are a key adaptation during hibernation and link cortisol to a reduced activation of the AMPK/PGC-1α/PPAR-α axis in the regulation of metabolism in skeletal muscle and adipose tissue. Moreover, our results indicate that during this phase of hibernation at a time when metabolic rate is significantly reduced metabolic adaptations in peripheral tissues seek to limit the detrimental effects of unduly large energy dissipation.
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http://dx.doi.org/10.1016/j.cbpa.2019.110591DOI Listing
February 2020

Associations of Sedentary Behavior and Abdominal Muscle Density: The Multi-Ethnic Study of Atherosclerosis.

J Phys Act Health 2018 11 9;15(11):827-833. Epub 2018 Oct 9.

Background: Sedentary behaviors (SB) may exacerbate loss of muscle mass and function, independent of physical activity levels. This study examined the associations of SB with abdominal muscle area and density, a marker of muscle quality, in adults.

Methods: A total of 1895 participants from the Multi-Ethnic Study of Atherosclerosis completed detailed health history, physical activity and SB questionnaires, computed tomography to quantify body composition, and measurements of inflammatory markers. Analyses included linear and nonlinear regression.

Results: The mean age and body mass index were 64.6 years and 28 kg·m, respectively, and 50% were women. On average, participants engaged in 28 metabolic equivalent hours·week of SB. With adjustment for age, sex, race/ethnicity, physical activity, cardiovascular disease risk factors, and inflammation, multivariable regression modeling revealed a nonlinear (quadratic) relationship between SB and locomotor, stability, and total abdominal muscle density (P < .01) but not muscle area. The SB inflection point at which locomotor, stability, and total abdominal muscle density began to decrease was 38.2, 39.6, and 39.2 metabolic equivalent hours·week of SB, respectively.

Conclusions: SB is associated with reduced muscle density when practiced as little as 5.5 metabolic equivalent hours·day. These findings may have important implications for SB guidelines for targeting skeletal muscle health in older adults.
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http://dx.doi.org/10.1123/jpah.2018-0028DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7304496PMC
November 2018

Associations of abdominal intermuscular adipose tissue and inflammation: The Multi-Ethnic Study of Atherosclerosis.

Obes Res Clin Pract 2018 Nov - Dec;12(6):534-540. Epub 2018 Sep 10.

Department of Family Medicine and Public Health, University of California San Diego, La Jolla, CA, United States.

Objective: This study examined the associations between abdominal IMAT area and density with inflammatory markers associated with cardiometabolic disease.

Methods: 1897 participants enrolled in the Multi-Ethnic Study of Atherosclerosis underwent computed tomography to quantify body composition and measurements of adiponectin, leptin, interleukin-6 (IL-6), C-reactive protein (CRP), and resistin.

Results: The mean age and body mass index of participants was 65years and 28kg/m, respectively, and 50% were female. After adjustment for age, sex, and race/ethnicity, as IMAT area increased and density decreased from the first to fourth quartile, markers of inflammation increased linearly (p<0.01). Using linear regression, and with adjustment for demographics, cardiovascular disease risk factors, and abdominal muscle area and density, a 1-standard deviation (SD) increase in total abdominal IMAT area was associated with a 21%, 36% and 20% higher IL-6, leptin, and CRP, respectively, and 19% lower adiponectin (p<0.001). With similar adjustment, a 1-SD decrease in total abdominal IMAT density was associated with a 14%, 32%, and 15% higher IL-6, leptin, and CRP, respectively, and 22% lower adiponectin (p<0.001). These associations were attenuated with the addition of visceral fat (p>0.05).

Conclusions: Abdominal IMAT area and density are associated with inflammatory markers, with these associations attenuated by central adiposity.
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http://dx.doi.org/10.1016/j.orcp.2018.08.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6230307PMC
March 2019

Predictors of change in affect in response to high intensity interval exercise (HIIE) and sprint interval exercise (SIE).

Physiol Behav 2018 11 28;196:211-217. Epub 2018 Aug 28.

Department of Movement Sciences and WWAMI Medical Education Program, University of Idaho, Moscow, ID 83844, USA.

Affect is typically positive at intensities below the lactate or ventilatory threshold, yet more aversive responses occur at supra-threshold intensities which may reduce positive perceptions of exercise. Completion of high intensity interval exercise (HIIE) typically elicits a reduction in affect, yet greater post-exercise enjoyment has been reported in response to HIIE versus moderate intensity continuous exercise (MICE). This study examined affectual responses to HIIE and sprint interval exercise (SIE) in 71 active men and women (age = 24.0 ± 4.8 year). Participants performed various HIIE and SIE regimes on the cycle ergometer during which affect (+5 - -5 scale), rating of perceived exertion (RPE, Borg 1-10 scale), and blood lactate concentration (BLa) were determined. Enjoyment was measured post-exercise using the PACES scale. Predictors of change in these variables in response to exercise were identified using multiple regression. Results showed a significant reduction in affect (p = .001) which was greater (p = .03) with SIE (-5.7 ± 2.7) compared to HIIE (-4.3 ± 2.4). Nevertheless, there was marked variability in the affect response across participants, as its change ranged from -1 to -7 units from pre- to post-exercise in 85% of all sessions. Sixty two percent of the change in affect seen across regimes was explained by baseline affect, BLa, and enjoyment. Significant associations were shown between the change in affect and baseline affect (r = -0.46, p < .001) and change in RPE (r = -0.59, p < .001). In addition, RPE significantly increased in response to HIIE (6.1 ± 1.7) and SIE (6.9 ± 2.0) but was not different (p = .050) between regimes. Our findings document an intensity-dependent relationship between affect and intensity during interval training, as supramaximal intensities elicit a larger decline in affect compared to submaximal intensities. In addition, pre-exercise affect is associated with the magnitude of change in affect reported in response to interval exercise.
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http://dx.doi.org/10.1016/j.physbeh.2018.08.017DOI Listing
November 2018

Associations of Abdominal Muscle Area and Radiodensity with Adiponectin and Leptin: The Multiethnic Study of Atherosclerosis.

Obesity (Silver Spring) 2018 07 7;26(7):1234-1241. Epub 2018 Jun 7.

Department of Family Medicine and Public Health, University of California San Diego, San Diego, California, USA.

Objective: This study examined the associations of muscle area and radiodensity with adiponectin and leptin.

Methods: A total of 1,944 participants who enrolled in the Multi-Ethnic Study of Atherosclerosis underwent computed tomography to quantify body composition and measurements of adiponectin, leptin, interleukin-6, C-reactive protein, and resistin.

Results: The mean age and BMI of participants were 64.7 years and 28.1 kg/m and 49% were female. With adjustment for age, gender, race/ethnicity, traditional cardiovascular disease risk factors, inflammatory biomarkers, physical activity, and sedentary behavior, a 1-SD increment in total abdominal, stability, and locomotor muscle area was associated with a 19%, 17%, and 12% lower adiponectin level, respectively (P < 0.01 for all) but not leptin (P > 0.05). Muscle radiodensity was more robustly associated with adiponectin and leptin in the multivariable linear regression models. That is, with full adjustment for all covariates, a 1-SD increment in total abdominal, stability, and locomotor muscle radiodensity was associated with a 31%, 31%, and 18% lower adiponectin level (P < 0.01 for all) and a 6.7%, 4.6%, and 8.1% higher leptin level (P < 0.05 for all), respectively.

Conclusions: The data suggest that increases in muscle area and radiodensity may have positive impacts on chronic inflammation and, in turn, reduce the risk of cardiometabolic disease.
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http://dx.doi.org/10.1002/oby.22208DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6014896PMC
July 2018

Understanding the Nature of Measurement Error When Estimating Energy Expenditure and Physical Activity via Physical Activity Recall.

J Phys Act Health 2018 07 26;15(7):543-549. Epub 2018 Mar 26.

Background: The National Health and Nutrition Examination Survey physical activity questionnaire (PAQ) is used to estimate activity energy expenditure (AEE) and moderate to vigorous physical activity (MVPA). Bias and variance in estimates of AEE and MVPA from the PAQ have not been described, nor the impact of measurement error when utilizing the PAQ to predict biomarkers and categorize individuals.

Methods: The PAQ was administered to 385 adults to estimate AEE (AEE:PAQ) and MVPA (MVPA:PAQ), while simultaneously measuring AEE with doubly labeled water (DLW; AEE:DLW) and MVPA with an accelerometer (MVPA:A).

Results: Although AEE:PAQ [3.4 (2.2) MJ·d] was not significantly different from AEE:DLW [3.6 (1.6) MJ·d; P > .14], MVPA:PAQ [36.2 (24.4) min·d] was significantly higher than MVPA:A [8.0 (10.4) min·d; P < .0001]. AEE:PAQ regressed on AEE:DLW and MVPA:PAQ regressed on MVPA:A yielded not only significant positive relationships but also large residual variances. The relationships between AEE and MVPA, and 10 of the 12 biomarkers were underestimated by the PAQ. When compared with accelerometers, the PAQ overestimated the number of participants who met the Physical Activity Guidelines for Americans.

Conclusions: Group-level bias in AEE:PAQ was small, but large for MVPA:PAQ. Poor within-participant estimates of AEE:PAQ and MVPA:PAQ lead to attenuated relationships with biomarkers and misclassifications of participants who met or who did not meet the Physical Activity Guidelines for Americans.
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http://dx.doi.org/10.1123/jpah.2017-0089DOI Listing
July 2018

The Effectiveness of Standing on a Balance Board for Increasing Energy Expenditure.

Med Sci Sports Exerc 2018 08;50(8):1710-1717

Exercise Physiology Research Laboratory, Department of Movement Sciences, University of Idaho, Moscow, ID.

Purpose: This study aimed to investigate differences in energy expenditure (EE), heart rate (HR), productivity, fatigue, and pain while performing desk work while sitting (SIT), standing (STAND), and standing on a balance board (BOARD).

Methods: Thirty healthy adults (60% female, age = 39.7 ± 11.8 yr, body mass index = 26.7 ± 5.0 kg·m) employed in sedentary-based jobs volunteered for this randomized crossover trial. Participants performed typing work in three different positions: SIT, STAND, and BOARD, each condition lasting 30 min. Oxygen consumption (V˙O2) was measured via indirect calorimetry, and EE was calculated using respiratory quotient and corresponding caloric equivalent values. Productivity was quantified by measuring words typed per minute, accuracy, and typing mistakes. Overall feelings of fatigue and pain were self-reported three times during each position using validated 10-cm visual analog scales. Repeated-measures ANOVA was used to assess differences in outcome variables across conditions.

Results: V˙O2 was significantly different among all conditions regardless of current standing desk use (SIT = 3.35 ± 0.53, STAND = 3.77 ± 0.48, BOARD = 3.92 ± 0.54 mL·kg·min, P < 0.001). EE (kcal·min) also differed (P < 0.001) among SIT (1.27 ± 0.22), STAND (1.42 ± 0.26), and BOARD (1.48 ± 0.29). Compared with sitting (67 ± 9 bpm), HR was higher in STAND (76 ± 11 bpm) and BOARD (76 ± 11 bpm, P < 0.001). Measures of productivity were not different across conditions (P > 0.05). Fatigue progressively increased over each 30-min condition, whereas pain in SIT and BOARD increased from minute 10 to minute 20 and then leveled off between minutes 20 and 30. For STAND, pain continued to increase over time.

Conclusion: Compared with sitting, a balance board may be effective for increasing EE without interfering with productivity in an occupational setting.
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http://dx.doi.org/10.1249/MSS.0000000000001595DOI Listing
August 2018

Associations between physical activity, resilience, and quality of life in people with inflammatory bowel disease.

Eur J Appl Physiol 2018 Apr 6;118(4):829-836. Epub 2018 Feb 6.

Department of Movement Sciences, University of Idaho, Moscow, ID, USA.

Aim: Research has shown that moderate-to-vigorous physical activity (MVPA) is associated with higher health-related quality of life (HRQOL) in healthy individuals. Recent studies have suggested that low- to moderate-intensity physical activity can be beneficial to HRQOL in people with inflammatory bowel diseases (IBD); however, studies investigating associations between MVPA and HRQOL in this population are lacking.

Purpose: To understand the relationships among walking, MVPA, resilience, and HRQOL in people with IBD.

Methods: People with IBD (n = 242) completed questions about physical activity, resilience and HRQOL. Pearson product-moment correlations and multiple regression analyses were used to identify associations between physical activity and HRQOL. Analysis of covariance was used to compare HRQOL over quartiles of walking and MVPA with demographic variables as covariates.

Results: Both walking and MVPA were independently associated with physical (β = 0.21 and β = 0.26, respectively; p ≤ 0.001) but not mental HRQOL (p > 0.05). Higher volumes of MVPA were significantly associated with physical HRQOL (quartile 1 40.3 ± 9.0 vs. quartile 4 47.4 ± 9.0; p < 0.001) while higher volumes of walking were associated with both physical and mental HRQOL (p ≤ 0.01).

Conclusions: The findings suggest that engaging in higher volumes of MVPA above 150 min/week and walking, particularly above 60 min/week, are associated with improved HRQOL in people with IBD. Research would benefit from investigating participation in MVPA as a coping strategy, in a longitudinal manner, to determine which modes of activity may be most beneficial to people with IBD.
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http://dx.doi.org/10.1007/s00421-018-3817-zDOI Listing
April 2018

High-intensity interval and moderate-intensity continuous training elicit similar enjoyment and adherence levels in overweight and obese adults.

Eur J Sport Sci 2017 Oct 9;17(9):1203-1211. Epub 2017 Aug 9.

c Department of Movement Sciences , University of Idaho , Moscow , ID , USA.

Background: High-intensity interval training (HIIT) has been shown to improve cardiometabolic health during supervised lab-based studies but adherence, enjoyment, and health benefits of HIIT performed independently are yet to be understood. We compared adherence, enjoyment, and cardiometabolic outcomes after 8 weeks of HIIT or moderate-intensity continuous training (MICT), matched for energy expenditure, in overweight and obese young adults.

Methods: 17 adults were randomized to HIIT or MICT. After completing 12 sessions of supervised training over 3 weeks, participants were asked to independently perform HIIT or MICT for 30 min, 4 times/week for 5 weeks. Cardiometabolic outcomes included cardiorespiratory fitness (VO peak), lipids, and inflammatory markers. Exercise enjoyment was measured by the validated Physical Activity Enjoyment Scale.

Results: Exercise adherence (93.4 ± 3.1% vs. 93.1 ± 3.7%, respectively) and mean enjoyment across the intervention (100.1 ± 4.3 vs. 100.3 ± 4.4, respectively) were high, with no differences between HIIT and MICT (p > .05). Similarly, enjoyment levels did not change over time in either group (p > .05). After training, HIIT exhibited a greater decrease in low-density lipoprotein cholesterol than MICT (-0.66 mmol L vs. -0.03 mmol L, respectively) and a greater increase in VO peak than MICT (p < .05, +2.6 mL kg min vs. +0.4 mL kg min, respectively). Interleukin-6 and C-reactive protein increased in HIIT (+0.5 pg mL and + 31.4 nmol L, respectively) and decreased in MICT (-0.6 pg mL and -6.7 nmol L, respectively, p < .05).

Conclusions: Our novel findings suggest that HIIT is enjoyable and has high unsupervised adherence rates in overweight and obese adults. However, HIIT may be associated with an increase in inflammation with short-term exercise in this population.
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http://dx.doi.org/10.1080/17461391.2017.1359679DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6104631PMC
October 2017

The Impact of Low Accelerometer Wear Time on the Estimates and Application of Sedentary Behavior and Physical Activity Data in Adults.

J Phys Act Health 2017 12 25;14(12):919-924. Epub 2017 Sep 25.

Background: This investigation sought to determine how accelerometer wear (1) biased estimates of sedentary behavior (SB) and physical activity (PA), (2) affected misclassifications for meeting the Physical Activity Guidelines for Americans, and (3) impacted the results of regression models examining the association between moderate to vigorous physical activity (MVPA) and a clinically relevant health outcome.

Methods: A total of 100 participants [age: 20.6 (7.9) y] wore an ActiGraph GT3X+ accelerometer for 15.9 (1.6) hours per day (reference dataset) on the hip. The BOD POD was used to determine body fat percentage. A data removal technique was applied to the reference dataset to create individual datasets with wear time ranging from 15 to 10 hours per day for SB and each intensity of PA.

Results: Underestimations of SB and each intensity of PA increased as accelerometer wear time decreased by up to 167.2 minutes per day. These underestimations resulted in Physical Activity Guidelines for Americans misclassification rates of up to 42.9%. The regression models for the association between MVPA and body fat percentage demonstrated changes in the estimates for each wear-time adherence level when compared to the model using the reference MVPA data.

Conclusions: Increasing accelerometer wear improves daily estimates of SB and PA, thereby also improving the precision of statistical inferences that are made from accelerometer data.
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http://dx.doi.org/10.1123/jpah.2016-0584DOI Listing
December 2017

Physical Activity and Adiposity-related Inflammation: The MESA.

Med Sci Sports Exerc 2017 05;49(5):915-921

1Department of Movement Sciences, University of Idaho, Moscow, ID; 2Department of Family and Preventive Medicine, University of California San Diego, San Diego, CA; 3Department of Medicine, Hematology/Oncology Division, University of Vermont, Colchester, VT; 4Department of Pathology and Laboratory Medicine, University of Vermont College of Medicine, Colchester, VT; 5Department of Health and Human Development, Montana State University, Bozeman, MT; 6Department of Clinical Cancer Prevention, University of Texas MD Anderson Cancer Center, Houston, TX; and 7Division of Cardiology, Ciccarone Center for the Prevention of Heart Disease, Johns Hopkins School of Medicine, Baltimore, MD.

Purpose: Physical activity is associated with decreased adiposity-related inflammation in adults. Whether this association is independent of central obesity is unknown but important for understanding the mechanisms associated with reducing cardiometabolic disease risk through physical activity. This study examined whether associations of physical activity and obesity-related inflammatory markers were independent of central adiposity.

Methods: Between 2002 and 2005, 1970 participants from the Multi-Ethnic Study of Atherosclerosis completed detailed health history and physical activity questionnaires, underwent physical measurements including computed tomography to quantify abdominal visceral and subcutaneous fat, and measurements of adiponectin, leptin, interleukin-6, tumor necrosis factor-alpha, and resistin. Statistical analyses included analysis of covariance and multivariable-adjusted regression.

Results: The mean (range) age of participants was 64.7 (55-84) yr and 50% were women. After adjustment for age and sex, and compared with the lowest quartile, inflammatory markers in the highest quartile of moderate-to-vigorous physical activity were 16% higher for adiponectin and 30%, 26%, and 9% lower for leptin, interleukin-6, and resistin, respectively (P < 0.05 for all). In linear regression adjusted for demographics, dyslipidemia, hypertension, diabetes, smoking, glomerular filtration rate, renin, and aldosterone, each standard deviation increment of moderate-to-vigorous physical activity was associated with significantly higher levels of adiponectin (β = 0.04) and lower levels of leptin (β = -0.06), interleukin-6 (β = -0.08), and resistin (β = -0.05, P < 0.05 for all). The associations with leptin, interleukin-6, and resistin were independent of total and central adiposity (P < 0.05), whereas the association between moderate-to-vigorous physical activity and adiponectin was attenuated by central adiposity (P > 0.05). There were no significant interactions by race/ethnicity or sex.

Conclusions: Moderate-to-vigorous physical activity was associated with a more favorable profile of inflammatory markers, independent of relevant cardiometabolic disease risk factors including central obesity.
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http://dx.doi.org/10.1249/MSS.0000000000001179DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5392139PMC
May 2017

The Decremental Protocol as an Alternative Protocol to Measure Maximal Oxygen Consumption in Athletes.

Int J Sports Physiol Perform 2016 Nov 24;11(8):1094-1099. Epub 2016 Aug 24.

Purpose: To determine whether a decremental protocol could elicit a higher maximal oxygen consumption (VOmax) than an incremental protocol in trained participants. A secondary aim was to examine whether cardiac-output (Q) and stroke-volume (SV) responses differed between decremental and incremental protocols in this sample.

Methods: Nineteen runners/triathletes were randomized to either the decremental or incremental group. All participants completed an initial incremental VOmax test on a treadmill, followed by a verification phase. The incremental group completed 2 further incremental tests. The decremental group completed a second VOmax test using the decremental protocol, based on their verification phase. The decremental group then completed a final incremental test. During each test, VO, ventilation, and heart rate were measured, and cardiac variables were estimated with thoracic bioimpedance. Repeated-measures analysis of variance was conducted with an alpha level set at .05.

Results: There were no significant main effects for group (P = .37) or interaction (P = .10) over time (P = .45). VOmax was similar between the incremental (57.29 ± 8.94 mL · kg · min) and decremental (60.82 ± 8.49 mL · kg · min) groups over time. Furthermore, Q and SV were similar between the incremental (Q 22.72 ± 5.85 L/min, SV 119.64 ± 33.02 mL/beat) and decremental groups (Q 20.36 ± 4.59 L/min, SV 109.03 ± 24.27 mL/beat) across all 3 trials.

Conclusions: The findings suggest that the decremental protocol does not elicit higher VOmax than an incremental protocol but may be used as an alternative protocol to measure VOmax in runners and triathletes.
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http://dx.doi.org/10.1123/ijspp.2015-0488DOI Listing
November 2016

Low Cardiorespiratory Fitness Is Associated with Markers of Insulin Resistance in Young, Normal Weight, Hispanic Women.

Metab Syndr Relat Disord 2016 06 23;14(5):272-8. Epub 2016 Feb 23.

3 Recreation, Exercise, and Sport Science Department, Western State Colorado University , Gunnison, Colorado.

Background: Low cardiorespiratory fitness (CRF) and its decline over time are predictors of the development of diabetes in black and Caucasian women, independent of obesity. It is unclear, however, if the adverse effect of low CRF on the risk of diabetes in Hispanic women is mediated by obesity. Our purpose was to determine the associations of CRF with markers of insulin resistance in 68 normal weight Hispanic women.

Methods: Obesity indicators included body mass index (BMI), body composition by DXA, and waist circumference. CRF was measured by indirect calorimetry. A glucose tolerance test was used to measure markers of insulin resistance: homeostasis model assessment, fasting insulin, 2-hr insulin, area under the curve insulin, qualitative insulin sensitivity check, and insulin sensitivity index. Pearson correlation and multiple regression analyses were used to identify associations between CRF and markers of insulin resistance. Multivariate ANOVA was used to compare markers of insulin resistance over quartiles of CRF.

Results: Low CRF was significantly associated with all markers of insulin resistance (P < 0.01). These associations were independent of age, BMI, waist circumference, family history of T2DM, and triglycerides (CRF standardized beta range: -0.27 to -0.46, P < 0.05). However, these associations were attenuated when body composition, specifically fat-free mass, was entered into the model (CRF standardized beta range: -0.03 to 0.21, P > 0.05). All markers of insulin resistance improved linearly across CRF quartiles (P < 0.05).

Conclusions: Our findings suggest that low CRF may be an important predictor of diabetes risk in Hispanic women and that fat-free mass rather than overall body adiposity mediates these relationships.
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http://dx.doi.org/10.1089/met.2015.0135DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4884336PMC
June 2016

The prevalence of adverse cardiometabolic responses to exercise training with evidence-based practice is low.

Diabetes Metab Syndr Obes 2015 29;8:73-8. Epub 2015 Jan 29.

Department of Movement Sciences, WWAMI Medical Education Program, University of Idaho, Moscow, ID, USA.

Background: The purpose of this study was to determine the prevalence of individuals who experienced exercise-induced adverse cardiometabolic response (ACR), following an evidence-based, individualized, community exercise program.

Methods: Prevalence of ACR was retrospectively analyzed in 332 adults (190 women, 142 men) before and after a 14-week supervised community exercise program. ACR included an exercise training-induced increase in systolic blood pressure of ≥10 mmHg, increase in plasma triglycerides (TG) of >37.0 mg/dL (≥0.42 mmol/L), or decrease in high-density lipoprotein cholesterol (HDL-C) of >4.0 mg/dL (0.12 mmol/L). A second category of ACR was also defined - this was ACR that resulted in a metabolic syndrome component (ACR-risk) as a consequence of the adverse response.

Results: According to the above criteria, prevalence of ACR between baseline and post-program was systolic blood pressure (6.0%), TG (3.6%), and HDL-C (5.1%). The prevalence of ACR-risk was elevated TG (3.2%), impaired fasting blood glucose (2.7%), low HDL-C (2.2%), elevated waist circumference (1.3%), and elevated blood pressure (0.6%).

Conclusion: Evidence-based practice exercise programming may attenuate the prevalence of exercise training-induced ACR. Our findings provide important preliminary evidence needed for the vision of exercise prescription as a personalized form of preventative medicine to become a reality.
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http://dx.doi.org/10.2147/DMSO.S76880DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4319718PMC
February 2015

Grizzly bears exhibit augmented insulin sensitivity while obese prior to a reversible insulin resistance during hibernation.

Cell Metab 2014 Aug;20(2):376-82

Department of Metabolic Disorders, Amgen, Inc., Thousand Oaks, CA 91360, USA. Electronic address:

The confluence of obesity and diabetes as a worldwide epidemic necessitates the discovery of new therapies. Success in this endeavor requires translatable preclinical studies, which traditionally employ rodent models. As an alternative approach, we explored hibernation where obesity is a natural adaptation to survive months of fasting. Here we report that grizzly bears exhibit seasonal tripartite insulin responsiveness such that obese animals augment insulin sensitivity but only weeks later enter hibernation-specific insulin resistance (IR) and subsequently reinitiate responsiveness upon awakening. Preparation for hibernation is characterized by adiposity coupled to increased insulin sensitivity via modified PTEN/AKT signaling specifically in adipose tissue, suggesting a state of "healthy" obesity analogous to humans with PTEN haploinsufficiency. Collectively, we show that bears reversibly cope with homeostatic perturbations considered detrimental to humans and describe a mechanism whereby IR functions not as a late-stage metabolic adaptation to obesity, but rather a gatekeeper of the fed-fasting transition.
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http://dx.doi.org/10.1016/j.cmet.2014.07.008DOI Listing
August 2014

Associations of objectively measured sedentary behavior, light activity, and markers of cardiometabolic health in young women.

Eur J Appl Physiol 2014 May 28;114(5):907-19. Epub 2014 Jan 28.

Department of Movement Sciences, University of Idaho, 875 Perimeter Drive, MS 2401, Moscow, ID, 83844-2401, USA.

Purpose: To investigate the associations among objectively measured sedentary behavior, light physical activity, and markers of cardiometabolic health in young women.

Methods: Cardiovascular disease risk factors, homeostasis model assessment for insulin resistance (HOMA-IR), lipid accumulation product, and inflammatory markers were measured in 50 young, adult women. Accelerometers were worn over 7 days to assess sedentary time (<150 counts min(-1)), light physical activity (150-2,689 counts min(-1)), and moderate-to-vigorous physical activity (MVPA; ≥2,690 counts min(-1)). Multivariate regression examined independent associations of sedentary behavior and light physical activity with cardiometabolic health. Covariates included MVPA, cardiorespiratory fitness (VO2peak) and body mass, and body composition.

Results: Sedentary behavior was associated with triglycerides (p = 0.03) and lipid accumulation product (p = 0.02) independent of MVPA. These associations were attenuated by VO2peak and body mass or body composition (p ≥ 0.05). Light physical activity was independently associated with triglycerides and lipid accumulation product after adjustment for all covariates (p < 0.05). The association between light physical activity and HOMA-IR was independent of MVPA (p = 0.02) but was attenuated by VO2peak and body mass or body composition (p > 0.05).

Conclusions: Sedentary behavior and light physical activity were independently associated with markers of cardiometabolic health in young, adult women. Our data suggest that VO2peak and body composition may be important mediators of these associations. Decreasing sedentary behavior and increasing light physical activity may be important for maintaining cardiometabolic health in young, adult women.
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http://dx.doi.org/10.1007/s00421-014-2822-0DOI Listing
May 2014

Muscle activation patterns and patellofemoral pain in cyclists.

Med Sci Sports Exerc 2014 Apr;46(4):753-61

1Department of Movement Science, University of Idaho, Moscow, ID, and 2Department of Biological Sciences, University of Idaho, Moscow, ID.

Introduction: Patellofemoral pain syndrome (PFPS) is pervasive and debilitating in the sport of cycling. Currently, little is known about the underlying mechanism causing patellofemoral pain in cyclists.

Purpose: The purpose of this study was to determine whether temporal differences in the muscle activity of the vastus medialis (VM), vastus lateralis (VL), semitendinosus (ST), and biceps femoris (BF) were correlated to patellofemoral pain in cycling.

Methods: Ten healthy cyclists (six women and four men, height = 1.74 ± 0.10 cm, weight = 71.9 ± 16.5 kg, cycling experience = 199.5 ± 82 miles · wk(-1)) and seven cyclists with PFPS (one woman and six men, height = 1.84 ± 0.08 cm, weight = 89.8 ± 9.4 kg, cycling experience = 228 ± 51 miles · wk(-1)) volunteered to participate in this study. Each participant completed a 10-min cycling trial during which surface EMG was recorded for the VM, VL, ST, and BF muscles. Sagittal plane knee kinematic data were recorded using an electrogoniometer.

Results: An ANOVA revealed no significant difference between groups for the differences in onset times of the VM and VL (P = 0.805). There were significant differences between groups for the differences in offset time of the VM and VL (P = 0.032), the differences in onset time of BF and ST (P < 0.001), and the differences in offset time of the ST and BF (P = 0.024). Root mean square values for BF activity were significantly higher in the PFPS group compared with the control (CTL) group (P < 0.01), and ST values were significantly lower in the PFPS group compared with the CTL group (P < 0.01). Root mean square values for BF were significantly greater than ST activity in the PFPS group (P < 0.01) but not in the CTL group (P > 0.05).

Conclusion: The results of this study indicate that trained cyclists with PFPS exhibit altered temporal characteristics in muscle activation patterns compared with trained cyclists without PFPS.
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http://dx.doi.org/10.1249/MSS.0000000000000153DOI Listing
April 2014

A proposed mechanism for exercise attenuated methylglyoxal accumulation: activation of the ARE-Nrf pathway and increased glutathione biosynthesis.

Med Hypotheses 2013 Nov 7;81(5):813-5. Epub 2013 Sep 7.

Department of Movement Science, University of Idaho, Moscow, ID 83844-2401, United States. Electronic address:

The dicarbonyl methylglyoxal (MGO) is an endogenous metabolite and a known intracellular precursor of advanced glycation endproducts (AGEs). High serum levels of MGO have been correlated with MGO-derived AGEs in individuals with type 2 diabetes (T2DM). Furthermore, there is human and animal evidence to suggest that MGO is causal in copious pathologies related to AGE accumulation including heart disease, hypertension, nephropathy and insulin resistance. MGO is detoxified through the glutathione (GSH) dependent glyoxalase system and diminished glutathione status results in impaired MGO detoxification. Individuals with uncontrolled T2DM have diminished GSH status, suggesting the increase in serum MGO can be partially attributed to impaired MGO detoxification. GSH biosynthesis is heavily dependent upon the antioxidant response element-nuclear respiratory factor pathway (ARE-Nrf) and pharmacological and dietary intervention studies have demonstrated that activation of the ARE-Nrf pathway increases intracellular GSH and glyoxalase enzymes and reduces MGO levels. Acute and chronic exercise has also been shown to increase activation of the ARE-Nrf pathway and GSH biosynthesis, and to improve GSH status. Therefore, we propose that exercise improves MGO detoxification and attenuates MGO accumulation by increasing GSH biosynthesis and improving GSH status through activation of the ARE-Nrf pathway.
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http://dx.doi.org/10.1016/j.mehy.2013.08.034DOI Listing
November 2013

Associations of insulin resistance with cardiovascular risk factors and inflammatory cytokines in normal-weight Hispanic women.

Diabetes Care 2013 May 28;36(5):1377-83. Epub 2012 Dec 28.

Department of Movement Sciences, University of Idaho, Moscow, ID, USA.

Objective: To investigate the associations of markers of insulin resistance with cardiovascular disease risk factors and inflammation in young, normal-weight, Hispanic women.

Research Design And Methods: Seventy-one normal-weight (BMI <25 kg/m(2)) Hispanic women (age, 20-39 years) participated in a fasting blood draw for glucose, insulin, lipids, and inflammatory markers; a glucose tolerance test; anthropometric and blood pressure measurements; body composition by dual-energy x-ray absorptiometry; and measurements of cardiorespiratory fitness via Vo2max and daily physical activity by accelerometer. RESULTS Six percent of participants had impaired fasting glucose, 14% had impaired glucose tolerance, and 48% had at least one cardiovascular disease risk factor. Homeostasis model assessment of insulin resistance (HOMA-IR) and fasting insulin were positively correlated with glucose, triglycerides, systolic blood pressure, and diastolic blood pressure, and were negatively correlated with adiponectin (P < 0.05). The 2-h insulin was positively correlated with diastolic blood pressure, triglycerides, and high-sensitivity C-reactive protein. HOMA-IR and fasting insulin remained significantly and positively related to glucose, triglycerides, and blood pressure after adjustment for body composition. The relationships between markers of insulin resistance and adiponectin and high-sensitivity C-reactive protein were attenuated after adjustment for body composition.

Conclusions: Surrogate markers of insulin resistance were associated with cardiovascular disease risk factors and inflammation in young, normal-weight, Hispanic women. Our findings suggest that HOMA-IR, fasting, and 2-h insulin may be important clinical markers for identifying young, normal-weight, Hispanic women who may be at risk for development of type 2 diabetes and cardiovascular disease. Our findings show the importance of early screening for prevention of type 2 diabetes and cardiovascular disease in this population.
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http://dx.doi.org/10.2337/dc12-1550DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3631836PMC
May 2013

Physical activity recommendations and cardiovascular disease risk factors in young Hispanic women.

J Sports Sci 2011 Jan;29(1):37-45

Department of Health, Physical Education, Recreation and Dance, University of Idaho, Moscow, ID 83804-3150, USA.

Despite the benefits associated with regular physical activity, there is little epidemiological evidence to support positive health outcomes when meeting physical activity guidelines in high-risk ethnic groups, such as Hispanic women. We compared cardiovascular disease risk factors between young Hispanic women who meet and those who do not meet current physical activity guidelines. Height, weight, waist circumference, and blood pressure were measured in 60 Hispanic women aged 20-39 years. Lipids, C-reactive protein, insulin, and glucose were assessed. Body composition and cardiovascular fitness were assessed by BodPod and maximal oxygen uptake (VO₂(max)) respectively. Participants wore an accelerometer and average minutes (assessed in 10-min bouts) spent in light, moderate, and hard daily activity for weekdays and weekends was determined. Seventy percent of participants did not meet the recommended physical activity guidelines, whereas 30% did so. Following current physical activity guidelines was associated with significantly lower mean cholesterol (mean ± s: 4.2 ± 0.8 vs. 4.7 ± 0.9 mmol · l⁻¹) and triglycerides (0.7 ± 0.3 vs. 1.1 ± 0.6 mmol · l⁻¹), and higher fat-free mass (43.3 ± 3.8 vs. 40.2 ± 5.1 kg) and relative (40.4 ± 7.6 vs. 35.6 ± 7.0 ml · kg⁻¹ · min⁻¹) and absolute (2.5 ± 0.3 vs. 2.1 ± 0.4 litres · min⁻¹) VO₂(max) (P < 0.05). These findings suggest an improved health status in women who meet versus those who did not meet current physical activity guidelines.
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http://dx.doi.org/10.1080/02640414.2010.520727DOI Listing
January 2011

Cardiac function and arteriovenous oxygen difference during exercise in obese adults.

Eur J Appl Physiol 2011 Jun 11;111(6):915-23. Epub 2010 Nov 11.

Department of Kinesiology, University of Texas at El Paso, 1101N Campbell, El Paso, TX 79902, USA.

The purpose of this study was to assess cardiac function and arteriovenous oxygen difference (a-vO(2) difference) at rest and during exercise in young, normal-weight (n = 20), and obese (n = 12) men and women who were matched for age and fitness level. Participants were assessed for body composition, peak oxygen consumption (VO(2peak)), and cardiac variables (thoracic bioimpedance)-cardiac index (CI), cardiac output (Q), stroke volume (SV), heart rate (HR), and ejection fraction (EF)-at rest and during cycling exercise at 65% of VO(2peak). Differences between groups were assessed with multivariate ANOVA and mixed-model ANOVA with repeated measures controlling for sex. Absolute VO(2peak) and VO(2peak) relative to fat-free mass (FFM) were similar between normal-weight and obese groups (Mean ± SEE 2.7 ± 0.2 vs. 3.3 ± 0.3 l min(-1), p = 0.084 and 52.4 ± 1.5 vs. 50.9 ± 2.3 ml kg FFM(-1) min(-1), p = 0.583, respectively). In the obese group, resting Q and SV were higher (6.7 ± 0.4 vs. 4.9 ± 0.1 l min(-1), p < 0.001 and 86.8 ± 4.3 vs. 65.8 ± 1.9 ml min(-1), p < 0.001, respectively) and EF lower (56.4 ± 2.2 vs. 65.5 ± 2.2%, p = 0.003, respectively) when compared with the normal-weight group. During submaximal exercise, the obese group demonstrated higher mean CI (8.8 ± 0.3 vs. 7.7 ± 0.2 l min(-1) m(-2), p = 0.007, respectively), Q (19.2 ± 0.9 vs. 13.1 ± 0.3 l min(-1), p < 0.001, respectively), and SV (123.0 ± 5.6 vs. 88.9 ± 4.1 ml min(-1), p < 0.001, respectively) and a lower a-vO(2) difference (10.4 ± 1.0 vs. 14.0 ± 0.7 ml l00 ml(-1), p = 0.002, respectively) compared with controls. Our study suggests that the ability to extract oxygen during exercise may be impaired in obese individuals.
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http://dx.doi.org/10.1007/s00421-010-1554-zDOI Listing
June 2011

Relationship of leptin, resting metabolic rate, and body composition in premenopausal hispanic and non-Hispanic White women.

Endocr Res 2010 ;35(3):95-105

Department of Kinesiology, University of Texas at El Paso, El Paso, Texas 79902, USA.

Objective: The purpose was to evaluate the relationships between fasting serum leptin, resting metabolic rate (RMR), and body composition in premenopausal Hispanic and non-Hispanic White (White) women.

Methods: Participants were 67 Hispanic and 43 White women who arrived at the laboratory in a fasted state for measurement of RMR by indirect calorimetry, bone mineral content measured by dual-energy X-ray absorptiometry, and body density measured by hydrodensitometry. Serum leptin levels were determined by EIA.

Results: Multiple regression analysis revealed that body mass and lean body mass were the best predictors of RMR. Leptin was not a significant predictor of RMR.

Conclusion: Further research needs to be done to examine the role of leptin on metabolism, especially in ethnic groups predisposed to development of obesity and related disorders.
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http://dx.doi.org/10.3109/07435800.2010.496088DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4635679PMC
December 2010

Acculturation and metabolic syndrome risk factors in young Mexican and Mexican-American women.

J Immigr Minor Health 2011 Feb;13(1):119-26

Department of Kinesiology, University of Texas, El Paso, TX 79902, USA.

Little is known about effects of acculturation on disease risk in young Mexican and Mexican-American women living in a border community. The purpose of this study was to examine relationships between acculturation and features of metabolic syndrome (MetS) in Mexican and Mexican-American women (n = 60) living in the largest US-Mexico border community. Acculturation was measured by the short acculturation scale for Hispanics and birthplace. Body composition was measured by Bod Pod and daily physical activity was measured by questionnaire and accelerometer. Increased acculturation was related to individual features of MetS and increased risk of MetS. These relationships were mediated by fat mass rather than inactivity. Fat mass mediates the relationships between acculturation and individual features of MetS in young Mexican and Mexican-American women. These findings suggest that fat mass, rather than inactivity, is an important contributor to disease risk in young Mexican and Mexican-American women living in a large US/Mexico border community.
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http://dx.doi.org/10.1007/s10903-009-9299-7DOI Listing
February 2011

Physical activity, cardiorespiratory fitness, and metabolic syndrome in young Mexican and Mexican-American women.

Appl Physiol Nutr Metab 2009 Feb;34(1):10-7

Exercise Physiology Laboratory, University of Texas at El Paso, El Paso, TX 79902, USA.

Young adult women have had the greatest increase in prevalence of metabolic syndrome (MetS) over time, and prevalence is highest in Hispanic women, compared with women of other ethnicities. Factors contributing to the high prevalence of MetS in Hispanic women are unknown. This study was conducted to determine if physical activity or fitness were associated with individual features of MetS in young Mexican and Mexican-American women, and if the associations were independent of fat mass. Sixty young Mexican and Mexican-American women participated in the study. MetS was defined according to the Adult Treatment Panel III. A fasting blood sample was drawn for the measurement of glucose, insulin, high-density lipoprotein cholesterol (HDL-c), and triglycerides. Physical activity was assessed by questionnaire and accelerometer. Fitness was assessed by progressive treadmill test to exhaustion and ventilatory threshold. Body composition was assessed with Bod Pod. Multivariate regression was used to establish the independent contributions of physical activity and fitness to the individual features of MetS. After controlling for fat mass and fat-free mass, physical activity was found to be independently related to HDL-c and fitness was found to be independently related to triglycerides (p < 0.05). The independent associations between physical activity, fitness, and features of MetS were mediated by, rather than independent of, fat mass. Fat mass was independently related to triglycerides, systolic blood pressure, and diastolic blood pressure. Although physical activity and fitness were related to features of MetS, these associations were not independent of fat mass.
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http://dx.doi.org/10.1139/H08-134DOI Listing
February 2009