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BACKGROUND: Health agencies recommend that homes of heat-vulnerable occupants (e.g., older adults) be maintained below 24–28°C to prevent heat-related mortality and morbidity. However, there is limited experimental evidence to support these recommendations. OBJECTIVE: To aid in the development of evidence-based guidance on safe indoor temperatures for temperate continental climates, we evaluated surrogate physiological outcomes linked with heat-related mortality and morbidity in older adults during simulated indoor overheating METHODS: Sixteen older adults [six women; median age: 72 y, interquartile range (IQR): 70-73 y; body mass index: 24.6 (IQR: 22.1-27.0 kg/m²] from the Ottawa, Ontario, Canada, region (warm summer continental climate) completed four randomized, 8-h exposures to conditions experienced indoors during hot weather in continental climates (e.g., Ontario, Canada; 64 participant exposures). Ambient conditions simulated an air-conditioned environment (22°C; control), proposed indoor temperature upper limits (26°C), and temperatures experienced in homes without air-conditioning (31°C and 36°C). Core temperature (rectal) was monitored as the primary outcome; based on previous recommendations, between-condition differences >0.3C were considered clinically meaningful. RESULTS: Compared with 22°C, core temperature was elevated to a meaningful extent in 31°C [+0.7C; 95% confidence interval (CI): 0.5, 0.8] and 36°C (+0.9C; 95% CI: 0.8, 1.1), but not 26°C (+0.2C, 95% CI: 0.0, 0.3). Increasing ambient temperatures were also associated with elevated heart rate and reduced arterial blood pressure and heart rate variability at rest, as well as progressive impairments in cardiac and blood pressure responses to standing from supine. DISCUSSION: Core temperature and cardiovascular strain were not appreciably altered following 8-h exposure to 26°C but increased progressively in conditions above this threshold. These data support proposals for the establishment of a 26°C indoor temperature upper limit for protecting vulnerable occupants residing in temperate continental climates from indoor overheating. [ABSTRACT FROM AUTHOR]

Introduction. Despite heightened risk of cardiovascular disease (CVD) among individuals with type 1 diabetes, few studies in this population have investigated the development of CVD using early markers in adolescence. We compared risk factors (blood pressure (BP) and dyslipidemia) and early markers of CVD between adolescents with and without type 1 diabetes and explored effect modification by sex. Methods. Cross-sectional study using data from the CARdiovascular Disease risk in pEdiatric type 1 diAbetes (CARDEA) study. We recruited 100 adolescents with type 1 diabetes at the Sainte-Justine University Hospital Center and 97 adolescents without diabetes (14–18 years). We measured arterial stiffness by carotid-femoral pulse wave velocity, endothelial function by brachial artery flow-mediated dilation test, as well as left ventricular (LV) mass, papillary mass, and wall thickness by cardiac MRI. We used multivariable linear regression models to assess the impact of type 1 diabetes on each outcome adjusting for age, sex, ethnicity, adiposity, and familial income. Results. Adolescents with type 1 diabetes had 0.21 standard deviations (SD) (95% CI: 0.04; 0.38) higher diastolic blood pressure z-score (zDBP), 0.21 mmol/L (95% CI: 0.02; 0.40) higher low-density lipoprotein cholesterol (LDL-c) levels, and 17% (95% CI: 4; 29) higher triglyceride levels and lower endothelial function based on acceleration (−77.4 cm/s2, 95% CI: −133.1; −21.6) compared with adolescents without diabetes. Girls with type 1 diabetes had higher systolic blood pressure z-score (zSBP), and boys with type 1 diabetes had lower LV mass and wall thickness compared to healthy peers. Conclusions. In addition to higher BP and abnormal lipid profiles, adolescents with type 1 diabetes present endothelial dysfunction and alterations in cardiac structure (in boys) compared to adolescents without diabetes, suggesting that CVD prevention should be incorporated into type 1 diabetes management early in the disease. [ABSTRACT FROM AUTHOR]

The article discusses the results of a study on the influence of caffeinated energy drinks on healthy adults' cardiovascular response during exercise. Topics mentioned include the significance of the study on people with hypertension, a description of exercise and intervention characteristics, and the range of ectopic beats and heart rate during the exercise.

Thiamin is a required coenzyme in energy production reactions that fuel myocardial contraction. Therefore, thiamin deficiency (TD) may aggravate cardiac dysfunction in patients with systolic heart failure (HF). To determine the prevalence of TD in ambulatory participants with HF as well as the relationships between thiamin status and HF severity, dietary thiamin intake, diuretic use, and circulating neurohormones. A cross-sectional study comparing the prevalence of TD in ambulatory patients with HF with that of controls. Demographic, anthropometric, nutrition, medication use, and heart function data were collected from direct interviewing, questionnaires, and medical records. Blood samples were obtained to measure levels of neurohormones and assess TD. Fifty age-matched control participants without HF and 100 outpatients with HF and reduced left ventricular function were recruited from clinics at St Michael's Hospital, University Health Network and Mount Sinai Hospital, Toronto, Ontario, Canada, between September 2009 and February 2011. To assess TD, erythrocyte thiamin pyrophosphate (TPP) was measured using high-performance liquid chromatography. TD was defined as TPP<6.07 μg/dL (180 nmol/L). Prevalence rates were analyzed using χ2 test. Nonparametric statistics (Jonckheere-Terpstra, Kruskal-Wallis, Spearman's correlation) were used to assess TPP levels in relation to HF severity, medication use and plasma concentrations of F2-isoprostanes, norepinephrine, and N-terminal pro-brain natriuretic peptide (NT-proBNP). There was no significant difference in the prevalence of TD in outpatients with HF (6%) and controls (6%) (P =0.99). No relationship was found between heart function, thiamin intake, use or dose of diuretics, and TD. A positive relationship was observed between erythrocyte TPP and F2-isoprostane levels (r s =0.22, P =0.03) but not between erythrocyte TPP and norepinephrine (P =0.45) and NT-proBNP (P =0.58). The prevalence of TD was low in ambulatory HF participants suggesting that, unlike hospitalized patients, ambulatory patients may be at a low risk for TD. [ABSTRACT FROM AUTHOR]

Background: Cardiovascular disease disproportionately affects North American Indigenous populations. Ethnic differences in cardiac responses to exercise are known, though Indigenous populations response is unknown. To evaluate cardiac responses to aerobic exercise among Canadian Indigenous and European adults. Methods: Indigenous (N = 12, 4 females, 1 male incomplete) and European (N = 12, all completed) Canadian age and sex-matched adults 19-40 years and free of cardiovascular disease or diabetes completed a cycle ergometer maximal aerobic power test and 30 min at 60% maximal aerobic capacity on two separate days. Echocardiographic assessments preceded and immediately followed exercise. Results: Responses to maximal exercise were similar among ethnicities including decreases in stroke volume index, cardiac output index and ejection fraction, and increases in arterial-ventricular coupling. However, following submaximal exercise, only Indigenous adults demonstrated reductions in end systolic volume, end diastolic volume (154.8 ± 40.6 mL to 136.5 ± 33.0 mL, p = 0.01, vs. 149.4 ± 22.4 mL to 147.1 ± 27.0 mL; p = 0.81), stroke volume index (44.9 ± 8.7 mL m−2 to 38.0 ± 6.5 mL m−2, p = 0.002, vs. 46.4 ± 7.1 mL m−2 to 44.0 ± 6.5 mL m−2; p = 0.28) and arterial compliance. Conclusion: Indigenous and European adults demonstrated similar cardiac responses to maximal exercise, though only Indigenous adults demonstrated cardiac responses to submaximal exercise. [ABSTRACT FROM AUTHOR]

Canadian physical activity guidelines recommend older adults accumulate 150 min of weekly moderate to vigorous physical activity (MVPA). Older adults who are insufficiently active may have reduced blood vessel health and an increased risk of cardiovascular disease. We tested this hypothesis in 11 older adults who did (7 female; age, 65 ± 5 years; MVPA, = 239 ± 81 min/week) and 10 older adults who did not (7 female; age, 68 ± 9 years; MVPA, 95 ± 33 min/week) meet MVPA guidelines. Flow-mediated dilation (FMD) in the brachial (BA) and popliteal (POP) arteries, as well as nitroglycerin-mediated dilation (NMD; endothelial-independent dilation) in the POP were assessed via ultrasonography. Aerobic fitness (peak oxygen uptake) was determined using a graded, maximal cycle ergometry test via indirect calorimetry. MVPA and sedentary time were assessed over 5 days using the PiezoRx and activPAL, respectively. There were no differences in peak oxygen uptake (26 ± 10 vs. 22 ± 10 mL O2/(kg·min); p = 0.26) or sedentary time (512 ± 64 vs. 517 ± 76 min/day; p = 0.87) between groups; however, those who achieved the MVPA guidelines had a higher BA-FMD (5.1% ± 1.3% vs. 3.6% ± 1.7%; p = 0.03), POP-FMD (2.6% ± 1.1% vs. 1.3% ± 0.8%; p = 0.006), and POP-NMD (5.1% ± 1.7% vs. 3.3% ± 2.1%; p = 0.04). In the pooled sample, MVPA was moderately correlated to both BA-FMD (r = 0.53; p = 0.01) and POP-NMD (r = 0.59; p = 0.005), and strongly correlated to POP-FMD (r = 0.85; p < 0.001). Collectively, our results provide supporting evidence that meeting MVPA guidelines is associated with better vascular function and may reduce the risk of developing cardiovascular disease in older adults. Furthermore, these data suggest that weekly MVPA time may have a greater impact on blood vessel function than aerobic fitness and weekly sedentary time. [ABSTRACT FROM AUTHOR]

This perspective document summarizes discussions held at the Canadian Society for Exercise Physiology Annual Meeting in Winnipeg on October 27, 2017, when an expert panel was assembled to discuss the key questions and challenges for future research in cardiovascular exercise physiology. We were inspired by the example of the late Dr. Mike Sharratt, an accomplished and impactful Professor in the Faculty of Kinesiology at the University of Waterloo. Dr. Sharratt had a unique ability to bring experts together and translate theory into action, with a central goal of optimizing the health benefits of exercise, particularly in the fields of cardiac rehabilitation and aging (University of Waterloo Applied Health Science Department 2016; University of Waterloo Health Science Newsletter, 10-1-2017 (http://uwaterloo.ca/applied-health-sciences/news/remembering-mike-sharratt)). [ABSTRACT FROM AUTHOR]

While we now appreciate that autonomic dysfunction can impact wheelchair rugby performance, this is currently not being assessed during classification, largely due to lack of a standardized and evidence‐based strategy to assess autonomic function. Our aim, therefore, was to establish the optimal autonomic testing protocol that best predicts cardiovascular capacity during competition by comprehensively examining autonomic function in elite wheelchair rugby athletes with cervical SCI and thereby enhance the standardized classification. Twenty‐six individuals with cervical SCI (C4‐C8; AIS A, B, C) participated in this study during the 2015 Parapan American Games in Toronto, Canada. Clinic autonomic testing included: sympathetic skin responses, baseline hemodynamics, orthostatic challenge test, and cold‐pressor tests. Further, we completed standard motor/sensory assessments and obtained each participants’ International Wheelchair Rugby Federation classification. These clinic metrics were correlated to in‐competition heart rate monitoring obtained during competition. The current study provides novel evidence that the change in systolic blood pressure during an orthostatic challenge test predicts approximately 50% of the in‐competition peak heart rate (P<.001). Conversely, International Wheelchair Rugby Federation classification was poorly associated with in‐competition peak heart rate (R2=.204; P<.05). Autonomic testing provides deep insight regarding preserved autonomic control after SCI that is associated with performance in elite wheelchair rugby athletes. As such, incorporating assessments of cardiovascular capacity in classification will help to ensure a level playing field and may obviate the need for practices such as boosting to gain an advantage due to poor cardiovascular control. [ABSTRACT FROM AUTHOR]

The average salt intake of people in Canada, the United States, and Europe is about 3,400mg of sodium per day, which exceeds the recommended intake levels set by various health organizations. The World Health Organization recommends a worldwide reduction of sodium intake to less than 2,000mg per day. Most research to date has focused on the negative effects of high-sodium intake; however, little information is available on the metabolic effects of low-sodium intakes. This review focuses on the hormonal changes associated with low-sodium diets, specially the hormones involved in metabolism and cardiovascular and renal function. Based largely on rodent studies, low-sodium diets have been associated with changes in glycemic control, energy metabolism, cardiovascular disease risk, cholesterol concentrations, inflammation, and functioning of the renin-angiotensin-aldosterone system. Overall, research has revealed mixed results regarding the impact of dietary sodium intake on various hormones. Further research is required to assess the effects of sodium reduction on hormones and their associated pathways in order to determine the likelihood of any unintended effects. [ABSTRACT FROM AUTHOR]

Background: Hypertrophic cardiomyopathy (HCM) is usually associated with marked diastolic dysfunction, characterized by impaired myocardial relaxation and increased myocardial stiffness. The noninvasive evaluation of diastolic function in these patients remains a challenge since usual methods have shown a modest correlation with invasive measurements of left ventricular (LV) relaxation and filling pressures. Methods and Results: We retrospectively analyzed 44 patients with obstructive HCM who underwent cardiac catheterization and echocardiography performed within 48 hours. Standard echocardiographic diastolic parameters and systolic and diastolic myocardial mechanics (including longitudinal and circumferential strain [S] and strain rate [Sr]), LV rotation, and early reverse rotation rate (fraction of early apical reverse rotation [FEARR]) were correlated with diastolic hemodynamic indices. Estimated LA pressure by echo and the LV end-diastolic pressure (LVEDP) or the LV pre-A pressure did not correlate. Longitudinal strain was low and circumferential strain was abnormally higher than normal. FEARR and negative dp/dt inversely correlated (R =−0.57, P = 0.0001), and early diastolic Sr to systolic Sr ratio (SrE/SrS) correlated with the LVEDP (r = 0.61, P < 0.0001). Furthermore, a SrE to SrS ratio ≥0.79 had a sensitivity of 87% and a specificity of 75% for predicting elevated LVEDP (≥15 mmHg). Average circumferential strain rate during atrial contraction and LV pre-A pressure (r =−0.62, P < 0.001) inversely correlated. Conclusions: FEARR is decreased in HCM and appears to be a good measure of diastolic dysfunction. Myocardial mechanics can be used to assess LV relaxation and filling pressures in patients with obstructive HCM. [ABSTRACT FROM AUTHOR]

Objectives: Anderson-Fabry disease (AFD) is a lysosomal storage disease, which can involve the heart, mimicking hypertrophic cardiomyopathy (HCM). The underlying mechanism of disease in AFD is an infiltrative, diffuse process, whereas HCM is a primary heart muscle condition with patchy distribution, which may prompt differences in myocardial mechanics. The aim of this study was to assess myocardial mechanics in AFD according to the presence of left ventricular hypertrophy (LVH) compared to nonobstructive HCM (NHCM) and healthy controls. Methods and Results: We carried out a single-center, retrospective study in a small, genetically confirmed AFD cohort, which was divided into a subgroup with LVH (LVH+, n = 19), and without LVH (LVH-, n = 21). Comparison groups were healthy controls (n = 40) and NHCM patients (n = 19). Vector Velocity Imaging was applied to two-dimensional echocardiography studies for assessment of longitudinal strain (LS), circumferential strain (CS), and base-to-apex CS gradients. AFD LVH+ patients had lower global LS than AFD LVH- patients (-14 ± 4% vs -17 ± 3%, P < 0.05), but similarly lowered global CS (-24 ± 5% vs -22 ± 5%, P = ns). AFD LVH+ and NHCM had similarly lowered global LS compared to normals, but significantly lower global CS was observed in AFD LVH+ (-24 ± 5% vs -28 ± 4%, P < 0.05), whereas it was significantly increased in NHCM (-31 ± 2% vs -28 ± 4%, P < 0.05). Unlike NHCM, in both AFD subgroups, patients lost their normal base-to-apex CS gradient. Conclusions: AFD patients without LVH already show abnormal systolic myocardial mechanics. Relevant differences in myocardial mechanics between AFD patients with LVH compared to NHCM reflect the different underlying mechanisms of disease. [ABSTRACT FROM AUTHOR]

To examine the association between racial discrimination experienced in childhood on allostatic load (AL) in adulthood, and whether this association differed by cultural continuity among Indigenous adults. Data were collected from Indigenous adults attending university in a small city in western Canada between 2015 and 2017 (N = 105). The frequency of childhood racial discrimination was measured using an item modified from the Experience of Discrimination Scale. AL was measured as a composite of 7 biomarkers assessing neuroendocrine, cardiovascular, metabolic, and immune system function. Cultural continuity was measured using the Vancouver Index Enculturation Scale. Bootstrapped linear regression models examined associations adjusted for confounders, with and without stratification by a dichotomized measure of Indigenous cultural continuity. Most Indigenous adults (72.3%) experienced racial discrimination some or most of the time in childhood. The frequency of child discrimination was significantly associated with AL, explaining 11% of the variance in adult AL score after adjustment for age and income. In the high cultural continuity group, there was no association between child discrimination and adult AL. In the low cultural continuity group, child discrimination was significantly associated with AL, explaining 21% of the variance in adult AL score. Childhood racial discrimination may have a biological toll on adult health through altered activation of the stress response system which could, over time, exacerbate health inequities in this population. High Indigenous cultural continuity served as a resilience factor that buffered the adverse impacts of childhood discrimination on adult AL score. • We sampled Indigenous adults attending university in a small city in western Canada between 2015 and 2017. • Childhood discrimination and adult allostatic load were positively associated. • The significance of the association varied by Indigenous cultural continuity. • Cultural continuitybuffered the impact of child discrimination on adult allostatic load. [ABSTRACT FROM AUTHOR]

Objective Determine how parental nutrition label use, label literacy, and nutrition knowledge may be associated with cardiovascular health in parents and their children. Design and Setting Cross-sectional analyses of 2006 data from the Healthy Heart Project in Montreal, Canada. Participants Among community recruited families, parents were predominantly mothers (n = 127 [80%]; mean age, 45.0 years) and half of their children were female (44%; mean age, 12.5 years). Main Outcome Measures Blood pressure, lipids, and weight. Nutrition label use, label literacy, and nutrition knowledge among parents were collected using existing scales. Analyses Multivariable linear regression models. Results Among parents, nutrition label use was associated with lower total cholesterol (B[SE] = −.53 [.20]; P = .009), lower low-density lipoprotein (B[SE] = −.57 [.21]; P = .007), and lower total cholesterol/high-density lipoprotein cholesterol ratio (B[SE] = −.82 [.30]; P = .008) but was not associated with adiposity. Among children, greater parental nutrition knowledge was associated with lower body mass index percentiles (B[SE] = −3.6 [1.49]; P = .02), lower waist circumference (B[SE] = −1.27 [.55]; P = .02), and lower percent body fat (B[SE] = −1.28 [.47]; P = .008). Parental nutrition label use or nutrition knowledge was not associated with children's lipids. Conclusions and Implications Parents with greater nutrition label use had more favorable lipids, but children's lipids were unaffected. Children of parents with greater nutrition knowledge had lower adiposity. Further research on the correlates of label use and health is needed. [ABSTRACT FROM AUTHOR]