Cherie Rooks

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 <VO(2)peak; and very hard - ≥VO(2)peak intensities) performed by 291 healthy people in 21 studies is accompanied by moderate-to-large increases (mean effect, dz±95% CI) in the prefrontal cortex of oxygenated hemoglobin (O(2)Hb) or other measures of oxygen level (O(2)Hbdiff) or saturation (SCO(2)) (0.92±0.67, 1.17), deoxygenated hemoglobin (dHb) (0.87±0.56, 1.19), and blood volume estimated by total hemoglobin (tHb) (1.21±0.84, 1.59). After peaking at hard intensities, cerebral oxygen levels dropped during very hard intensities. People who were aerobically trained attained higher levels of cortical oxygen, dHb, and tHb than untrained people during very hard intensities. Among untrained people, a marked drop in oxygen levels and a small increase in dHb at very hard intensities accompanied declines in tHb, implying reduced blood flow. In 6 studies of 222 patients with heart or lung conditions, oxygenation and dHb were lowered or unchanged during exercise compared to baseline. In conclusion, prefrontal oxygenation measured with NIRS in healthy people showed a quadratic response to incremental exercise, rising between moderate and hard intensities, then falling at very hard intensities. Training status influenced the responses. While methodological improvements in measures of brain oxygen are forthcoming, these results extend the evidence relevant to existing models of central limitations to maximal exercise.

Post-traumatic stress disorder and incidence of coronary heart disease: a twin study.

OBJECTIVES The aim of this study was to determine whether post-traumatic stress disorder (PTSD) is associated with coronary heart disease (CHD) using a prospective twin study design and objective measures of CHD. BACKGROUND It has long been hypothesized that PTSD increases the risk of CHD, but empirical evidence using objective measures is limited. METHODS We conducted a prospective study of middle-aged male twins from the Vietnam Era Twin Registry. Among twin pairs without self-reported CHD at baseline, we selected pairs discordant for a lifetime history of PTSD, pairs discordant for a lifetime history of major depression, and pairs without either condition. All underwent a clinic visit after a median follow-up of 13 years. Outcomes included clinical events (myocardial infarction, other hospitalizations for CHD and coronary revascularization) and quantitative measures of myocardial perfusion by [(13)N] ammonia positron emission tomography, including a stress total severity score and coronary flow reserve. RESULTS A total of 562 twins (281 pairs) with a mean age of 42.6 years at baseline were included in this study. The incidence of CHD was more than double in twins with PTSD (22.6%) than in those without PTSD (8.9%; p < 0.001). The association remained robust after adjusting for lifestyle factors, other risk factors for CHD, and major depression (odds ratio: 2.2; 95% confidence interval: 1.2 to 4.1). Stress total severity score was significantly higher (+95%, p = 0.001) and coronary flow reserve was lower (-0.21, p = 0.02) in twins with PTSD than in those without PTSD, denoting worse myocardial perfusion. Associations were only mildly attenuated in 117 twin pairs discordant for PTSD. CONCLUSIONS Among Vietnam-era veterans, PTSD is a risk factor for CHD.

Status of Cardiovascular Health in US Adolescents

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.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. # Clinical Perspective {#article-title-48}

Sex differences in mental stress-induced myocardial ischemia in young survivors of an acute myocardial infarction.

Objectives Emotional stress may disproportionally affect young women with ischemic heart disease. We sought to examine whether mental stress–induced myocardial ischemia (MSIMI), but not exercise-induced ischemia, is more common in young women with previous myocardial infarction (MI) than in men. Methods We studied 98 post-MI patients (49 women and 49 men) aged 38 to 60 years. Women and men were matched for age, MI type, and months since MI. Patients underwent technetium-99m sestamibi perfusion imaging at rest, after mental stress, and after exercise/pharmacological stress. Perfusion defect scores were obtained with observer-independent software. A summed difference score (SDS), the difference between stress and rest scores, was used to quantify ischemia under both stress conditions. Results Women 50 years or younger, but not older women, showed a more adverse psychosocial profile than did age-matched men but did not differ for conventional risk factors and tended to have less angiographic coronary artery disease. Compared with age-matched men, women 50 years or younger exhibited a higher SDS with mental stress (3.1 versus 1.5, p = .029) and had twice the rate of MSIMI (SDS ≥3; 52% versus 25%), whereas ischemia with physical stress did not differ (36% versus 25%). In older patients, there were no sex differences in MSIMI. The higher prevalence of MSIMI in young women persisted when adjusting for sociodemographic and life-style factors, coronary artery disease severity, and depression. Conclusions MSIMI post-MI is more common in women 50 years or younger compared with age-matched men. These sex differences are not observed in post-MI patients who are older than 50 years.

Early trauma and inflammation: role of familial factors in a study of twins.

Objective Although early trauma (trauma in childhood) has been linked to adult inflammation and adult disease of inflammatory origin, it remains unknown whether this relationship is due to long-term consequences of early life stress or other familial factors. Methods We examined 482 male middle-aged twins (241 pairs) born between 1946 and 1956 from the Vietnam Era Twin Registry. Childhood traumatic experiences, before the age of 18 years, were measured retrospectively with the Early Trauma Inventory and included physical, sexual, emotional abuse and general trauma. Lifetime major depressive disorder and posttraumatic stress disorder were assessed with the Structured Clinical Interview for DSM-IV. Traditional risk factors for cardiovascular disease were also assessed. Plasma C-reactive protein and interleukin 6 were measured to determine levels of inflammation. Mixed-effects regression models with a random intercept for pair were used to separate between– and within–twin pair effects. Results When twins were analyzed as individuals, increasing levels of early trauma were positively related to C-reactive protein (p = .03) but not to interleukin 6 (p = .12). When estimating within- and between-pair effects, only the between-pair association of early trauma with the inflammatory markers remained significant. Conclusions The link between early trauma and inflammation is largely explained by familial factors shared by the twins because levels of inflammation were highest when both twins were exposed to trauma. Exposure to early trauma may be a marker for an unhealthy familial environment. Clarification of familial factors associated with early stress and adult inflammation will be important to uncover correlates of stress and disease.

Association between anger and mental stress–induced myocardial ischemia

BACKGROUND Mental stress-induced myocardial ischemia is associated with adverse prognosis in coronary artery disease patients. Anger is thought to be a trigger of acute coronary syndromes and is associated with increased cardiovascular risk; however, little direct evidence exists for a link between anger and myocardial ischemia. METHODS [(99m)Tc]-sestamibi single-photon emission tomography was performed at rest, after mental stress (a social stressor with a speech task) and after exercise/pharmacologic stress. Summed scores of perfusion abnormalities were obtained by observer-independent software. A summed-difference score, the difference between stress and rest scores, was used to quantify myocardial ischemia under both stress conditions. The Spielbergers State-Trait Anger Expression Inventory was used to assess different anger dimensions. RESULTS The mean age was 50 years, 50% were female, and 60% were non-white. After adjusting for demographic factors, smoking, coronary artery disease severity, depressive, and anxiety symptoms, each IQR increment in state-anger score was associated with 0.36 U-adjusted increase in ischemia as measured by the summed-difference score (95% CI 0.14-0.59); the corresponding association for trait anger was 0.95 (95% CI 0.21-1.69). Anger expression scales were not associated with ischemia. None of the anger dimensions was related to ischemia during exercise/pharmacologic stress. CONCLUSION Anger, both as an emotional state and as a personality trait, is significantly associated with propensity to develop myocardial ischemia during mental stress but not during exercise/pharmacologic stress. Patients with this psychologic profile may be at increased risk for silent ischemia induced by emotional stress, and this may translate into worse prognosis.

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.

Depressive symptoms are associated with mental stress-induced myocardial ischemia after acute myocardial infarction.

Objectives Depression is an adverse prognostic factor after an acute myocardial infarction (MI), and an increased propensity toward emotionally-driven myocardial ischemia may play a role. We aimed to examine the association between depressive symptoms and mental stress-induced myocardial ischemia in young survivors of an MI. Methods We studied 98 patients (49 women and 49 men) age 38–60 years who were hospitalized for acute MI in the previous 6 months. Patients underwent myocardial perfusion imaging at rest, after mental stress (speech task), and after exercise or pharmacological stress. A summed difference score (SDS), obtained with observer-independent software, was used to quantify myocardial ischemia under both stress conditions. The Beck Depression Inventory-II (BDI-II) was used to measure depressive symptoms, which were analyzed as overall score, and as separate somatic and cognitive depressive symptom scores. Results There was a significant positive association between depressive symptoms and SDS with mental stress, denoting more ischemia. After adjustment for demographic and lifestyle factors, disease severity and medications, each incremental depressive symptom was associated with 0.14 points higher SDS. When somatic and cognitive depressive symptoms were examined separately, both somatic [β = 0.17, 95% CI: (0.04, 0.30), p = 0.01] and cognitive symptoms [β = 0.31, 95% CI: (0.07, 0.56), p = 0.01] were significantly associated with mental stress-induced ischemia. Depressive symptoms were not associated with ischemia induced by exercise or pharmacological stress. Conclusion Among young post-MI patients, higher levels of both cognitive and somatic depressive symptoms are associated with a higher propensity to develop myocardial ischemia with mental stress, but not with physical (exercise or pharmacological) stress.

Effects of smoking on coronary microcirculatory function: A twin study

BACKGROUND In asymptomatic smokers, coronary microcirculatory dysfunction, assessed by coronary flow reserve (CFR), is an early indicator of cardiovascular risk. Inflammation and oxidative stress may be the mechanisms through which smoking affects the microvasculature. OBJECTIVES The purpose of this study was to determine the relationship between smoking and CFR, taking into account potential shared genetic effects. METHODS We examined 360 male middle aged twins (288 non-smokers and 72 smokers), including 46 twin pairs discordant for current smoking. Coronary flow reserve (CFR) in response to adenosine was measured with positron emission tomography [N(13)] ammonia and quantitation of coronary blood flow at rest and after adenosine stress. Inflammation was assessed by measuring interleukin-6 and C-reactive protein, and oxidative stress was determined by measuring plasma hydroperoxides, glutathione (GSH), the oxidized form of GSH, GSSG, and the ratio of GSH to GSSG. RESULTS CFR was significantly lower in smokers compared to nonsmokers (2.25 vs. 2.75, p<0.01). This relationship persisted after accounting for known cardiovascular disease risk factors, and was marginally affected by adjusting for inflammatory and oxidative stress biomarkers. In addition, in smoking-discordant twin pairs, CFR in the smoking twin was significantly lower than in the non-smoking co-twin (2.25 vs. 2.67, p=0.03) even after adjustment for cardiovascular risk factors. CONCLUSIONS Our results demonstrate the adverse effects of smoking in the early phases of cardiovascular disease. Mechanisms other than peripherally measured inflammation and oxidative stress are involved.

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.