Young women post-MI have higher plasma concentrations of interleukin-6 before and after stress testing.

OBJECTIVES: Young women have poorer prognosis after myocardial infarction (MI) and a higher rate of mental stress-induced ischemia compared with similarly aged men. A higher inflammatory status may help explain these sex differences. METHODS: We examined 98 patients (49 women and 49 men) age 18-59years with recent MI (past 6months). Women and men were matched for age, type of MI, and time since MI. Interleukin 6 (IL-6) concentrations were measured at baseline, after mental stress using a speech task, and after exercise/pharmacologic stress (60 and 90min). Depressive symptoms were measured with the Beck Depression Inventory (BDI-II) and angiographic coronary artery disease (CAD) severity was quantified with the Gensini score. Single-photon emission computed tomography (SPECT) was used to obtain a computerized measurement of stress-induced ischemia (summed difference score, or SDS) and determine whether severity of stress-induced ischemia affects the inflammatory response to stress. Analysis was stratified by the median age of 50. Geometric mean concentrations of IL-6 were obtained from general linear regression models. RESULTS: In both age groups, women had less angiographic CAD and a similar level of conventional risk factors compared with men. Despite this, baseline IL-6 geometric means before both mental and physical stress were twice as high in women ⩽50years of age compared to age-matched men (3.8 vs. 1.8pg/mL, p=0.001, across both conditions), while they were similar in women and men age >50years (2.3 vs. 2.2pg/mL, p=0.83). After mental stress, IL-6 concentrations increased in both women and men in a similar fashion and remained twice as high in women ⩽50years than men at both 60min (5.4 vs. 2.6pg/mL, p=0.002) and 90min (5.9 vs. 3.4pg/mL, p=0.01). No significant difference was found between women and men >50years of age at any time point after mental stress. Results were similar for physical stress. After accounting for SDS, IL-6 concentrations in young women remained higher after both mental and physical stress. Baseline IL-6 concentrations were not significantly related to inducible ischemia. CONCLUSIONS: After MI, young women aged 50years or younger, compared with age-matched men, have remarkably higher concentrations of inflammation at baseline and after both mental and physical stress, with a similar inflammatory response to both stressors. Sustained concentrations of inflammation in young women, not their response to stress, may contribute to their adverse outcomes post-MI.

Status of cardiovascular health in US adolescents: prevalence estimates from the National Health and Nutrition Examination Surveys (NHANES) 2005-2010.

BACKGROUND: The American Heart Association recently developed definitions and metrics for monitoring the spectrum of cardiovascular health in adolescents and children. Current nationally representative prevalence estimates according to sex and race/ethnicity are unavailable. METHODS AND RESULTS: We examined the components of cardiovascular health in 4673 participants aged 12 to 19 years (representing ≈33.2 million US adolescents) from the 2005-2010 National Health and Nutrition Examination Surveys. Population prevalence of individual cardiovascular health behaviors and factors was estimated according to American Heart Association criteria for poor, intermediate, and ideal levels. Ideal blood pressure was most prevalent (males, 78%; females, 90%), whereas a dramatically low prevalence of ideal Healthy Diet Score was observed (males, <1%; females, <1%). Females exhibited a lower prevalence of ideal total cholesterol (65% versus 72%, respectively) and ideal physical activity levels (44% versus 67%, respectively) yet a higher prevalence of ideal blood glucose (89% versus 74%, respectively) compared with males. Approximately two thirds of adolescents exhibited ideal body mass index (males, 66%; females, 67%) and ideal smoking status (males, 66%; females, 70%). Less than 50% of adolescents exhibited ≥5 ideal cardiovascular health components (45%, males; 50%, females). Prevalence estimates according to sex were consistent across race/ethnic groups. CONCLUSIONS: The low prevalence of ideal cardiovascular health behaviors in US adolescents, particularly physical activity and dietary intake, will likely contribute to a worsening prevalence of obesity, hypertension, hypercholesterolemia, and dysglycemia as the current US adolescent population reaches adulthood. Population-wide emphasis on establishment of ideal cardiovascular health behaviors early in life is essential for maintenance of ideal cardiovascular health throughout the lifespan.

Acute exercise improves endothelial function despite increasing vascular resistance during stress in smokers and nonsmokers.

The present study examined the effect of acute exercise on flow mediated dilation (FMD) and reactivity to neurovascular challenges among female smokers and nonsmokers. FMD was determined by arterial diameter, velocity, and blood flow measured by Doppler ultrasonography after forearm occlusion. Those measures and blood pressure and heart rate were also assessed in response to forehead cold and the Stroop Color-Word Conflict Test (CWT) before and after 30 min of rest or an acute bout of cycling exercise (∼50% VO2 peak). Baseline FMD and stress responses were not different between smokers and nonsmokers. Compared to passive rest, exercise increased FMD and decreased arterial velocity and blood flow responses during the Stroop CWT and forehead cold in both groups. Overall, acute exercise improved endothelial function among smokers and nonsmokers despite increasing vascular resistance and reducing limb blood flow during neurovascular stress.

Meeting U.S. Healthy People 2010 levels of physical activity: agreement of 2 measures across 2 years.

BACKGROUND: Measuring the way people vary across time in meeting recommended levels of physical activity should be a fundamental component of public health surveillance. However, we were unaware of prospective cohort studies that had examined this in a population base using convergent measures. PURPOSE: We examined agreement between two validated measures used to estimate periodic change in the rate of meeting U.S. Healthy People 2010 guidelines for participation in moderate or vigorous physical activity. METHODS: A cohort (N = 497) from a random, multiethnic sample of adults living in Hawaii was assessed every 6-months for 2 years starting spring 2004. Latent transition analysis classified people as meeting or not meeting the guidelines. Intra-class kappa statistics and multinomial logistic regression analysis were used to evaluate agreement. RESULTS: Agreement for classifying stable classes of people who met or did not meet the guideline each time was substantial for vigorous activity (kappa approximately 0.65-0.70) but fair-to-moderate for moderate activity (kappa approximately 0.38-0.48). Agreement was poorer for classifying people who transitioned between meeting and not meeting the vigorous guideline (kappa approximately 0.45) or the moderate guideline (kappa approximately 0.21-0.29). CONCLUSIONS: Rates of meeting the guidelines varied across time and were estimated differently by the two measures, especially for moderate activity. This finding illustrates an understudied problem for public health promotion. Accurate classification of change within people is necessary for determining exposure in outcome studies, personal determinants of sufficient activity, and for evaluating whether interventions are successful in sustaining increases in rates of meeting physical activity guidelines.

Effects of incremental exercise on cerebral oxygenation measured by near-infrared spectroscopy: a systematic review.

We conducted a systematic review and meta-regression analysis to quantify effects of exercise on brain hemodynamics measured by near-infrared spectroscopy (NIRS). The results indicate that acute incremental exercise (categorized relative to aerobic capacity (VO(2)peak) as low - <30% VO(2)peak; moderate - ≥30% VO(2)peak to <60% VO(2)peak; hard - ≥60% VO(2)peak to

Failure of post-action stages of the transtheoretical model to predict change in regular physical activity: a multiethnic cohort study.

BACKGROUND: Predicting variation in meeting recommended levels of physical activity is important for public health evaluation. PURPOSE: The purpose of this study is to determine the predictive value of stages of the Transtheoretical Model (TTM) for classifying people who meet the US Healthy People 2010 guideline for regular physical activity. METHODS: A cohort (N = 497) from a random, multiethnic sample of 700 adults living in Hawaii was assessed at 6-month intervals three or more times for 2 years. Latent transition analysis was used to classify people according to TTM stages and separately according to whether they met the guideline. The predictive value of pre- vs. post-action stages was then tested. RESULTS: Stages were more likely to falsely classify people as meeting the guideline than to falsely classify them as not meeting it. Probabilities of predicting 6-month transitions were about 50% for the stable class of meeting the guideline each time and just 25% for transitions between meeting and not meeting the guideline. CONCLUSION: The TTM post-action stages had limited usefulness in this cohort. Further longitudinal study is needed to determine whether TTM stages can accurately classify transitions from physical inactivity to physical activity below recommended levels.

Sympathetic denervation does not prevent a reduction in fat pad size of rats or mice treated with peripherally administered leptin.

Leptin increases sympathetic nervous system (SNS) activity in brown adipose tissue and renal nerves. Experiments described here tested whether SNS innervation is required for peripheral, physiological concentrations of leptin to reduce body fat. In experiment 1, one epididymal (EPI) fat pad was sympathectomized by local injection of 6-hydroxydopamine (6OHDA) in C57BL/6 mice that were then infused for 13 days with PBS or 10 microg leptin/day from an intraperitoneal miniosmotic pump. Surprisingly, EPI denervation increased total body fat of PBS-infused mice but leptin decreased the size of both injected and noninjected EPI pads in 6OHDA mice. Experiment 2 was identical except for the use of male Sprague-Dawley rats that were infused with 50 microg leptin/day. Leptin had little effect on EPI weight or norepinephrine (NE) content, but denervation of one EPI pad decreased the effect of leptin on intact EPI, inguinal and retroperitoneal (RP) fat and increased the size of the mesenteric fat pad. Experiment 3 included groups in which either one EPI or one RP pad was denervated. RP denervation reduced RP NE content but did not prevent a leptin-induced reduction in fat pad mass. Therefore, the SNS is not required for low doses of leptin to reduce body fat. EPI denervation significantly increased adipocyte number in contralateral EPI and RP fat pads and this was prevented by leptin. These changes in intact pads of rats with one denervated fat pad imply communication between fat depots and suggest that both leptin and the SNS regulate the size of individual depots.