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Background: Using data from a multiethnic cohort, the authors tested associations of multiple types and intensities of physical activity (PA) with abdominal muscle area and density. Methods: 1895 Multiethnic Study of Atherosclerosis participants (mean age 64.6 [9.6] y) completed health history and PA questionnaires and computed tomography to quantify body composition and measurements of cardiovascular and inflammatory biomarkers. Analyses included multivariable regression. Results: Compared with those not meeting PA guidelines for Americans, those meeting the guidelines had higher total abdominal muscle area (odds ratio, 95% confidence interval 1.60, 1.20 to 2.15), stability muscle area (1.68, 1.28 to 2.20), and stability muscle density (1.35, 1.03 to 1.76). After adjustment for relevant covariates, each SD increase in total moderate to vigorous PA was associated with a higher total abdominal (β, 95% confidence interval = 0.068, 0.036 to 0.173), stability (0.063, 0.027 to 0.099), and locomotor (0.069, 0.039 to 0.099) muscle area and higher locomotor muscle density (0.065, 0.022 to 0.108, P P Conclusions: Most types of PA are positively associated with abdominal muscle area and density across functional categories, independent of relevant covariates. These results provide additional evidence for promoting PA for healthy muscle aging.

N-terminal pro-B-type natriuretic peptide (NT-proBNP) is used to identify cardiac stress, manage, and treat cardiac disease progression, and diagnose heart failure (HF). Notably, this peptide is paradoxically lower in HF patients who are obese. In this regard, a growing body of evidence has investigated its association with body composition, but the relationship between NT-proBNP and muscle quality is unknown. Therefore, we investigated the associations between abdominal muscle volume and density with NT-proBNP. We conducted a cross-sectional analysis of participants from the MESA Abdominal Body Composition, Inflammation, and Cardiovascular Disease (ABC) ancillary study. At exams 2 and 3, participants underwent abdominal computed tomography (CT) scans and had venous blood drawn. Images were analyzed using software (MIPAV 41.2), and Hounsfield units (HU) were used to determine the density of muscle groups of interest (total abdominal muscle [oblique, rectus abdominus, paraspinus muscles, psoas], stabilization muscles [oblique, rectus abdominus, paraspinus muscle] and, psoas muscle). NT-proBNP was log-transformed due to the skewed distribution of the variable. Fat, lean, and total tissue areas were measured in square centimeters. Multivariable linear regression models were used to test the associations between muscle quantity and quality (area and density), separately, with adjustment for age, sex, race/ethnicity, diabetes, smoking, hypertension, moderate-to-vigorous (MVPA), sedentary behavior, height, subcutaneous fat, visceral fat, visceral fat density, leptin, adiponectin, CRP, IL-6, and TNF-alpha. We included 1,489 participants with a mean age 64.8 (9.6) years, and 51.6% were female. The majority were non-Hispanic White (42%), followed by Hispanics (26%), African Americans (18%), and Chinese Americans (14%). After full adjustment, stabilization muscle density was inversely associated with NT-proBNP (β = -0.024, 95% CI: -0.038, -0.010). The results were similar for total abdominal muscle density (β = -0.026, 95% CI: -0.042, -0.010) and psoas muscle density (β = -0.013, 95% CI: -0.026, -0.001). For the latter, addition of muscle area as a covariate attenuated the association β = -0.011, 95% CI: -0.025, 0.002). After minimal adjustment, multivariable models of total abdominal muscle and psoas muscle areas for NT-proBNP were inversely associated but became non-significant with the addition of inflammation biomarkers (leptin, adiponectin, CRP, IL- 6, and TNF-alpha) and muscle density. Area of stabilization muscles and NT-proBNP were not significantly associated. Abdominal muscle area and NT-proBNP were not consistently associated, whereas abdominal muscle density and NT-proBNP were robustly inversely associated independently of muscle area, sociodemographic characteristics, cardiovascular risk factors, and inflammation biomarkers.

Background: Inflammatory bowel diseases (IBD) are a group of autoimmune diseases characterized by the cyclical nature of flare and remission periods that can affect health-related quality of life (HRQOL). Physical activity can benefit HRQOL in the general population and in individuals with chronic diseases. However, there is a paucity of data on physical activity and HRQOL in IBD. The purpose was to characterize physical activity, sitting, HRQOL, and resilience levels in people with IBD (in remission and disease flare) compared with healthy controls.Methods: Participants with IBD (n = 242; 96 in disease flare and 146 in disease remission) and healthy controls (n = 265) reported levels of physical activity, sitting, HRQOL, and resilience. Data were analyzed using analysis of covariance, with demographic variables as covariates.Results: IBD participants reported lower physical activity and resilience than controls (P < 0.05) with no differences between disease states. Time spent sitting was not different across groups (P = 0.07). There were lower scores of physical and mental HRQOL in people with IBD (44.2 ± 9.7 and 40.7 ± 11.7, respectively) than controls (55.9 ± 6.0 and 48.1 ± 10.0, respectively; P < 0.001).Conclusion: Our findings suggest that people with IBD have lower levels of physical activity, HRQOL, and resilience than healthy controls but no difference in time spent sitting. There were no apparent negative consequences of a disease flare on physical activity and resilience levels; however, those in a flare reported reduced HRQOL. Research should begin to focus on physical activity or mental skills training interventions for improving HRQOL in people with IBD, particularly those in a disease flare.

Introduction: A single bout of uninterrupted sitting impairs vascular function in the legs, which may be due to reductions in blood flow and shear stress. Participating in regular moderate-to-vigorous physical activity (MVPA) has been identified as an effective approach for improving vascular function, and recent evidence suggests meeting the physical activity (PA) guidelines may attenuate some of the negative health outcomes associated with excessive sedentary behavior; however, it is not well understood how meeting the PA guidelines may influence the acute response to sitting. Our aim was to investigate the effects of 3 h of uninterrupted sitting on hemodynamics and vascular and inflammatory biomarkers in physically inactive and active adults. Hypothesis: We hypothesized active adults would experience less detrimental physiological changes after sitting compared to inactive adults. Methods: Eleven inactive (mean±SD, age: 47.1±8.9 y, body fat: 33.1±8.5%; 78.5% women) and 16 active adults (age: 46.1±8.9 y, body fat: 25.2±7.2%; 31.1% women) completed 3 h of uninterrupted sitting. Adults self-reported their PA with the International PA Questionnaire. Adults engaging in ≥150 min·wk -1 were classified as active and -1 , inactive. Hemodynamic variables, and superficial femoral artery (SFA) diameter and blood velocity were measured each hour over 3 h of sitting. Mean arterial pressure, blood flow and shear rate were calculated. Serum vascular and inflammatory biomarkers were measured pre and post sitting. Linear mixed-effects modeling was used to assess changes in dependent variables over time and between inactive and active adults, controlling for sex. Results: Inactive and active adults self-reported 7.3±7.1 and 93.3±64.8 min·d -1 of MVPA, respectively. Endothelin-1 (baseline: 8.3±13.4 pg/mL, post: 81.1±103.0 pg/mL; p-1 ; 1 h: 55.0±27.4 s -1 ; 2 h: 45.3±24.2 s -1 ; 3 h: 40.8±25.5 s -1 ) while active participants demonstrated no change (baseline: 36.6±21.4 s -1 ; 1 h: 28.1±21.4 s -1 ; 2 h: 26.1±20.9 s -1 ; 3 h: 23.8±19.5 s -1 ). Inactive adults also had a higher oscillatory shear index compared to active adults (p Conclusion: Uninterrupted sitting induced unfavorable changes regardless of PA status; however, active adults demonstrated a more favorable shear profile. Meeting PA guidelines may attenuate some unfavorable changes within the vasculature associated with prolonged sitting.

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−2, respectively, and 50% were women. On average, participants engaged in 28 metabolic equivalent hours·week−1 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 −1 of SB, respectively. Conclusions: SB is associated with reduced muscle density when practiced as little as 5.5 metabolic equivalent hours·day−1. These findings may have important implications for SB guidelines for targeting skeletal muscle health in older adults.

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&rsquo, behavioral intentions to protect their health is important for developing these strategies. We conducted a survey within three communities of northern Idaho, USA (n = 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.

BackgroundLean muscle plays critical roles in physical functioning and metabolism. However, little is known regarding associations between muscle and mortality in adults.ObjectiveThe 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.DesignData 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 cm2. 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.ResultsAt 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

Introduction: Fat infiltration into muscle reduces muscle density and increases the risk for metabolic dysfunction, mobility disability and mortality. We assessed abdominal muscle density and muscle area in relation to incident coronary heart disease (CHD) events. Methods: Adults (mean age 64.6 ± 9.6) from the Multi-Ethnic Study of Atherosclerosis body composition ancillary study had computed tomography (CT)-derived measures of muscle density, muscle area and visceral fat at the L2-L4 spinal column levels between 2002-05 and were followed for incident events. Using sex-stratified Cox proportional hazards regression, associations of muscle density and muscle area (in the same model) with CHD events were assessed using restricted cubic splines with adjustment for confounders including visceral adiposity and BMI. Results: After 10.3±2.9 years of follow up, 924 males had 70 CHD (7.6%) events and 945 females had 44 CHD (4.7%) events. Muscle density was higher in males (44.5±4.9 HU) than females (40.1±5.2 HU), as was muscle area (116.7±23.9 vs. 80.4±23.9 cm 2 , respectively). Among males, and in mutually adjusted models, each incremental SD of muscle density was inversely associated with CHD (HR=0.67; 95%CI=0.49-0.92), while each SD of muscle area was associated with higher risk of CHD (HR=1.75; 95%CI=1.34-2.28; Figure). Overall patterns were similar but less strong among females for density (HR=0.79; 95%CI=0.50-1.22) and area (HR=1.17; 95%CI=0.79-1.73). Conclusions: Greater muscle density is associated with lower CHD risk, while greater muscle size is associated with increased CHD risk. These associations were independent of traditional CHD risk factors and measures of visceral and total body adiposity. Quantity and quality of skeletal muscle may represent distinct aspects of aging and physical functioning that are important in heart health.

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 (p≤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.

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).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.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, P0.001). EE (kcal·min) also differed (P0.001) 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, P0.001). Measures of productivity were not different across conditions (P0.05). 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.Compared with sitting, a balance board may be effective for increasing EE without interfering with productivity in an occupational setting.

We examined whether screen time was associated with cardiometabolic disease (CMD) risk factors in young adults. Ninety-five adults (19.9±11.4 y) 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 (VO(2)peak), 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(−1)) accounted for 24% of total sedentary time (8.4±1.5 h·day(−1)). After adjustment for demographics, smoking, sleep duration, total energy intake, total sedentary time and MVPA, a 1-standard deviation (SD) 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 VO(2)peak (p

Author(s): Vella, Chantal A; Cushman, Mary; Van Hollebeke, Rachel B; Allison, Matthew A | Abstract: ObjectiveThis study examined the associations of muscle area and radiodensity with adiponectin and leptin.MethodsA 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.ResultsThe mean age and BMI of participants were 64.7 years and 28.1 kg/m2 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 l 0.01 for all) but not leptin (P g 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 l 0.01 for all) and a 6.7%, 4.6%, and 8.1% higher leptin level (P l 0.05 for all), respectively.ConclusionsThe 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.

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. 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. 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

Food sources for North America’s grizzly bear (Ursus arctos horribilis Ord, 1815) population have changed as habitats have fragmented, altering available resources and putting bears in contact with unnatural foods. Bears have evolved mechanisms to tolerate obesity, and do not develop adverse health consequences despite storing massive amounts of body fat. Captive adult grizzly bears were used to determine the effects of dietary fat on health. Group 1 was fed a diet high in polyunsaturated fatty acids (PUFA) wherein 9.5% of available calories came from saturated fatty acids (SFA). Group 2 was fed a diet wherein 28.8% of calories came from SFA. Plasma fatty acids, serum lipid profiles, insulin, inflammatory markers, systolic and diastolic blood pressure, and cardiac function parameters were measured. Serum lipids, SFA, and insulin did not differ between the two groups, although omega-3 fatty acids differed. Bears eating the SFA diet had significantly higher circulating adiponectin, interleukin-7 and interleukin-15, and tumor necrosis factor-alpha. Mild, asymptomatic systolic and diastolic dysfunctions were detected by strain echocardiography in the SFA group. The SFA diet group exhibited higher diastolic arterial pressures. Even though mild metabolic derangements were observed, grizzly bears were remarkably resistant to metabolic effects of diets high in SFA.

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.

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.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.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).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.

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.

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−1] was not significantly different from AEE:DLW [3.6 (1.6) MJ·d−1; P > .14], MVPA:PAQ [36.2 (24.4) min·d−1] was significantly higher than MVPA:A [8.0 (10.4) min·d−1; P 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.

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 65 years and 28 kg/m(2), 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 (p0.05). CONCLUSIONS: Abdominal IMAT area and density are associated with inflammatory markers, with these associations attenuated by central adiposity.

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.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 (VOExercise 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 LOur 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.

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.

PurposePhysical 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.MethodsBetween 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.ResultsThe 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.ConclusionsModerate-to-vigorous physical activity was associated with a more favorable profile of inflammatory markers, independent of relevant cardiometabolic disease risk factors including central obesity.

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) years and 50% were female. After adjustment for age and sex, and compared to 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 (p0.05). 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.

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.

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 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.

Grizzly bears (Ursus arctos horribilis) have evolved remarkable metabolic adaptations including enormous fat accumulation during the active season followed by fasting during hibernation. However, these fluctuations in body mass do not cause the same harmful effects associated with obesity in humans. To better understand these seasonal transitions, we performed insulin and glucose tolerance tests in captive grizzly bears, characterized the annual profiles of circulating adipokines, and tested the anorectic effects of centrally administered leptin at different times of the year. We also used bear gluteal adipocyte cultures to test insulin and beta-adrenergic sensitivity in vitro. Bears were insulin resistant during hibernation but were sensitive during the spring and fall active periods. Hibernating bears remained euglycemic, possibly due to hyperinsulinemia and hyperglucagonemia. Adipokine concentrations were relatively low throughout the active season but peaked in mid-October prior to hibernation when fat content was greatest. Serum glycerol was highest during hibernation, indicating ongoing lipolysis. Centrally administered leptin reduced food intake in October, but not in August, revealing seasonal variation in the brain’s sensitivity to its anorectic effects. This was supported by strong phosphorylated signal transducer and activator of transcription 3 labeling within the hypothalamus of hibernating bears; labeling virtually disappeared in active bears. Adipocytes collected during hibernation were insulin resistant when cultured with hibernation serum but became sensitive when cultured with active season serum. Heat treatment of active serum blocked much of this action. Clarifying the cellular mechanisms responsible for the physiology of hibernating bears may inform new treatments for metabolic disorders.

AIM: The effects of obesity on cardiac function during incremental exercise to peak oxygen consumption (VO(2peak)) have not been previously described. The purpose of this study was to compare submaximal and maximal cardiac function during exercise in normal-weight and obese adults. METHODS: Normal-weight (n = 20; means ± SE: age = 21.9 ± 0.5 years; BMI = 21.8 ± 0.4 kg m(-2)) and obese (n = 15; means ± SE: age = 25.1 ± 5.2 years; BMI = 34.1 ± 01.0 kg m(-2)) participants were assessed for body composition, VO(2peak) and cardiac variables (thoracic bioimpedance analysis) at rest and at heart rates (HR) of 110, 130, 150 and 170 beats min(-1) and maximal HR during incremental cycling exercise to exhaustion. Differences between groups were assessed with mixed-model ancova with repeated measures. Cardiac variables were statistically indexed for body surface area and resting HR. VO(2) and arteriovenous oxygen difference (a-vO(2)) were statistically indexed for fat-free mass and resting HR. RESULTS: Significant main effects for group indicated obese participants had higher cardiac output (Q) index and stroke volume (SV) index but lower ejection fraction (EF) and a-vO(2) index during incremental exercise to exhaustion compared with their normal-weight peers, despite similar submaximal and maximal VO(2) and absolute power outputs (P < 0.05). CONCLUSIONS: Our findings suggest that although Q index and SV index were higher in obese, young adults, EF and a-vO(2) index were significantly lower when compared to matched, normal-weight adults.

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.

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.