Right ventricle best predicts the race performance in amateur ironman athletes

PURPOSE The ironman (IM) triathlon is a popular ultraendurance competition, consisting of 3.8 km of swimming, 180.2 km of cycling, and 42.2 km of running. The aim of this study was to investigate the predictors of IM race time, comparing echocardiographic findings, anthropometric measures, and training characteristics. METHODS Amateur IM athletes (ATHL) participating in the Zurich IM race in 2010 were included. Participants were examined the day before the race by a comprehensive echocardiographic examination. Moreover, anthropometric measurements were obtained the same day. During the 3 months before the race, each IM-ATHL maintained a detailed training diary. Recorded data were related to total IM race time. RESULTS Thirty-eight IM finishers (mean ± SD age = 38 ± 9 yr, 32 men [84%]) were evaluated. Total race time was 684 ± 89 min (mean ± SD). For right ventricular fractional area change (45% ± 7%, Spearman ρ = -0.33, P = 0.05), a weak correlation with race time was observed. Race performance exhibited stronger associations with percent body fat (15.2 ± 5.6%, ρ = 0.56, P = 0.001), speed in running training (11.7 ± 1.2 km · h(-1), ρ = -0.52, P = 0.002), and left ventricular myocardial mass index (98 ± 24 g · m(-2), ρ = -0.42, P = 0.009). The strongest association was found between race time and right ventricular end-diastolic area (22 ± 4 cm2, ρ = -0.64, P < 0.0001). In multivariate analysis, right ventricular end-diastolic area (β = -16.7, 95% confidence interval = -27.3 to -6.1, P = 0.003) and percent body fat (β = 6.8, 95% confidence interval = 1.1-12.6, P = 0.02) were independently predictive of IM race time. CONCLUSIONS In amateur IM-ATHL, RV end-diastolic area and percent body fat were independently related to race performance. RV end-diastolic area was the strongest predictor of race time. The role of the RV in endurance exercise may thus be more important than previously thought and needs to be further studied.

Impact de l’indice glycémique sur la performance physique de cyclistes de haut niveau

Plusieurs études ont démontré que la consommation d’un repas à indice glycémique bas (LGI) avant un exercice physique favorisait l’oxydation des lipides, diminuait les épisodes d’hypoglycémie et améliorait la performance. Par contre, d’autres recherches n’ont pas observé ces bénéfices. Le but de cette étude consiste à démontrer l’impact de l’ingestion de déjeuners avec différents indices glycémiques (IG) sur la performance en endurance de cyclistes de haut niveau. Dix cyclistes masculins ont complété trois protocoles attribués de façon aléatoire, séparés par un intervalle minimal de sept jours. Les trois protocoles consistaient en une épreuve contre la montre, soit trois heures après avoir consommé un déjeuner à indice glycémique bas ou élevé contenant 3 grammes de glucides par kg de poids corporel, soit à compléter l’exercice à jeun. Les résultats obtenus pour le temps de course montrent qu’il n’y pas de différence significative entre les protocoles. Par contre, on observe que le nombre de révolutions par minute (RPM) est significativement plus élevé avec le protocole à indice glycémique élevé (HGI) (94,3 ± 9,9 RPM) comparativement au protocole à jeun (87,7 ± 8,9 RPM) (p<0,005). Au niveau de la glycémie capillaire, on observe que durant l’exercice, au temps 30 minutes, la glycémie est significativement supérieure avec le protocole à jeun (5,47 ± 0,76 mmol/L) comparé à HGI (4,99 ± 0,91 mmol/L) (p<0,002). Notre étude n’a pas permis de confirmer que la consommation d’un repas LGI avant un exercice physique améliorait la performance physique de façon significative. Cependant, notre recherche a démontré que la diversité des protocoles utilisés pour évaluer l’impact de l’indice glycémique sur la performance physique pouvait occasionner des variations positives dans les temps de courses. Par conséquent, il s’avère nécessaire de faire d’autres recherches qui reproduisent les situations de compétition de l’athlète soit la course contre la montre.

Genetic evaluation of performance traits in Brazilian Quarter Horse

The aim of this study was to estimate genetic parameters for racing performance traits in Quarter Horses in Brazil. The data (provided by the Sorocaba Jockey Club) came from 3 Brazilian hippodromes in 1994-2003, with 11875 observations of race time and 7775 of the speed index (Sl), distributed in 2403 and 2169 races, respectively. The variance components were estimated by the MTGSAM program, under animal models including the random additive genetic effect, random permanent environmental effect, and the fixed effects of sex, age and race. Heritabilities for race time and the SI, for the 3 distances studied (301, 365 and 402 in), varied from 0.26 to 0.41 and from 0. 14 to 0. 19, respectively, whereas repeatabilities varied from 0.36 to 0.68 (time) and from 0.27 to 0.42 (SI) and the genetic correlations from 0.90 to 0.97 (time) and from 0.67 to 0.73 (SI).

Estudio cuantitativo de los tiempos en las carreras de purasangre en pistas de tierra y césped en Brasil

This study was conducted to estimate the genetic parameters for race times on turf and dirt tracks of Thoroughbred race horses. Data used were recorded by the Turftotal Ltd. for 343,419 racing performance of 26,713 animals, from January 1992 to January 2003. The model used in analysis included random animal and permanent environmental effects, and age, post position at start, sex and race as fixed effects. The variance and covariance components and the breeding value were estimated using the MTGSAM software. Heritability estimates were 0.29 for time on dirt track and 0.25 for time on turf track, indicating a moderate association between the animals' breeding values and their phenotypic values. Although genetic and environmental variances were smaller in turf tracks, their repeatability was equal to that of dirt (0.56), in terms of the highest estimated phenotypic variance for the latter type of track. The genetic correlation between times on different tracks was high (0.70). Considering the mean breeding value of the progeny of 465 stallions with 10 or more offspring, Spearman's correlation was 0.80, indicating that most Thoroughbred stallions produce offspring suited to both dirt and turf racing tracks.

Gender differences of atrial and ventricular remodeling and autonomic tone in nonelite athletes

Veteran endurance athletes have an increased risk of developing atrial fibrillation (AF), with a striking male predominance. We hypothesized that male athletes were more prone to atrial and ventricular remodeling and investigated the signal-averaged P wave and factors that promote the occurrence of AF. Nonelite athletes scheduled to participate in the 2010 Grand Prix of Bern, a 10-mile race, were invited. Of the 873 marathon and nonmarathon runners who were willing to participate, 68 female and 70 male athletes were randomly selected. The runners with cardiovascular disease or elevated blood pressure (>140/90 mm Hg) were excluded. Thus, 121 athletes were entered into the final analysis. Their mean age was 42 ± 7 years. No gender differences were found for age, lifetime training hours, or race time. The male athletes had a significantly longer signal-averaged P-wave duration (136 ± 12 vs 122 ± 10 ms; p <0.001). The left atrial volume was larger in the male athletes (56 ± 13 vs 49 ± 10 ml; p = 0.001), while left atrial volume index showed no differences (29 ± 7 vs 30 ± 6 ml/m²; p = 0.332). In male athletes, the left ventricular mass index (107 ± 17 vs 86 ± 16 g/m²; p <0.001) and relative wall thickness (0.44 ± 0.06 vs 0.41 ± 0.07; p = 0.004) were greater. No differences were found in the left ventricular ejection fraction (63 ± 4% vs 66 ± 6%; p = 0.112) and mitral annular tissue Doppler e' velocity (10.9 ± 1.5 vs 10.6 ± 1.5 cm/s; p = 0.187). However, the tissue Doppler a' velocity was higher (8.7 ± 1.2 vs 7.6 ± 1.3 cm/s; p < 0.001) in the male athletes. Male athletes had a higher systolic blood pressure at rest (123 ± 9 vs 110 ± 11 mm Hg; p < 0.001) and at peak exercise (180 ± 15 vs 169 ± 19 mm Hg; p = 0.001). In the frequency domain analysis of heart rate variability, the sympatho-vagal balance, represented by the low/high-frequency power ratio, was significantly greater in male athletes (5.8 ± 2.8 vs 3.9 ± 1.9; p < 0.001). Four athletes (3.3%) had at least one documented episode of paroxysmal AF, all were men (p = 0.042). In conclusion, for a comparable amount of training and performance, male athletes showed a more pronounced atrial remodeling, a concentric type of ventricular remodeling, and an altered diastolic function. A higher blood pressure at rest and during exercise and a higher sympathetic tone might be causal. The altered left atrial substrate might facilitate the occurrence of AF.

Inflammation and atrial remodeling after a mountain marathon

Endurance athletes have an increased risk of atrial fibrillation. We performed a longitudinal study on elite runners of the 2010 Jungfrau Marathon, a Swiss mountain marathon, to determine acute effects of long-distance running on the atrial myocardium. Ten healthy male athletes were included and examined 9 to 1 week prior to the race, immediately after, and 1, 5, and 8 days after the race. Mean age was 34.9 ± 4.2 years, and maximum oxygen consumption was 66.8 ± 5.8 mL/kg*min. Mean race time was 243.9 ± 17.7 min. Electrocardiographic-determined signal-averaged P-wave duration (SAPWD) increased significantly after the race and returned to baseline levels during follow-up (128.7 ± 10.9 vs. 137.6 ± 9.8 vs. 131.5 ± 8.6 ms; P < 0.001). Left and right atrial volumes showed no significant differences over time, and there were no correlations of atrial volumes and SAPWD. Prolongation of the SAPWD was accompanied by a transient increase in levels of high-sensitivity C-reactive protein, proinflammatory cytokines, total leucocytes, neutrophil granulocytes, pro atrial natriuretic peptide and high-sensitivity troponin. In conclusion, marathon running was associated with a transient conduction delay in the atria, acute inflammation and increased atrial wall tension. This may reflect exercise-induced atrial myocardial edema and may contribute to atrial remodeling over time, generating a substrate for atrial arrhythmias.

Training-related modulations of the autonomic nervous system in endurance athletes: is female gender cardioprotective?

The risk of sudden death is increased in athletes with a male predominance. Regular physical activity increases vagal tone, and may protect against exercise-induced ventricular arrhythmias. We investigated training-related modulations of the autonomic nervous system in female and male endurance athletes. Runners of a 10-mile race were invited. Of 873 applicants, 68 female and 70 male athletes were randomly selected and stratified according to their average weekly training hours in a low (≤4 h) and high (>4 h) volume training group. Analysis of heart rate variability was performed over 24 h. Spectral components (high frequency [HF] and low frequency [LF] power in normalized units) were analyzed for hourly 5 min segments and averaged for day- and nighttime. One hundred and fourteen athletes (50 % female, mean age 42 ± 7 years) were included. No significant gender difference was observed for training volume and 10-mile race time. Over the 24-h period, female athletes exhibited a higher HF and lower LF power for each hourly time-point. Female gender and endurance training hours were independent predictors of a higher HF and lower LF power. In female athletes, higher training hours were associated with a higher HF and lower LF power during nighttime. In male athletes, the same was true during daytime. In conclusion, female and male athletes showed a different circadian pattern of the training-related increase in markers of vagal tone. For a comparable amount of training volume, female athletes maintained their higher markers of vagal tone, possibly indicating a superior protection against exercise-induced ventricular arrhythmias.

Masked hypertension and cardiac remodeling in middle-aged endurance athletes

OBJECTIVES: Extensive endurance training and arterial hypertension are established risk factors for atrial fibrillation. We aimed to assess the proportion of masked hypertension in endurance athletes and the impact on cardiac remodeling, mechanics, and supraventricular tachycardias (SVT). METHODS: Male participants of a 10-mile race were recruited and included if office blood pressure was normal (<140/90 mmHg). Athletes were stratified into a masked hypertension and normotension group by ambulatory blood pressure. Primary endpoint was diastolic function, expressed as peak early diastolic mitral annulus velocity (E'). Left ventricular global strain, left ventricular mass/volume ratio, left atrial volume index, signal-averaged P-wave duration (SAPWD), and SVT during 24-h Holter monitoring were recorded. RESULTS: From 108 runners recruited, 87 were included in the final analysis. Thirty-three (38%) had masked hypertension. The mean age was 42 +/- 8 years. Groups did not differ with respect to age, body composition, cumulative training hours, and 10-mile race time. Athletes with masked hypertension had a lower E' and a higher left ventricular mass/volume ratio. Left ventricular global strain, left atrial volume index, SAPWD, and SVT showed no significant differences between the groups. In multiple linear regression analysis, masked hypertension was independently associated with E' (beta = -0.270, P = 0.004) and left ventricular mass/volume ratio (beta = 0.206, P = 0.049). Cumulative training hours was the only independent predictor for left atrial volume index (beta = 0.474, P < 0.001) and SAPWD (beta = 0.481, P < 0.001). CONCLUSION: In our study, a relevant proportion of middle-aged athletes had masked hypertension, associated with a lower diastolic function and a higher left ventricular mass/volume ratio, but unrelated to left ventricular systolic function, atrial remodeling, or SVT.

BLOOD PRESSURE CHANGES IN RELATION TO DEMOGRAPHIC, ANTHROPOMETRIC, AND SEXUAL MATURATION VARIABLES IN U.S. HEALTH EXAMINATION SURVEY OF CHILDREN AND YOUTHS (UNITED STATES)

The determinants of change in blood pressure during childhood and adolescence were studied in a cohort of U.S. national probability sample of 2146 children examined on two occasions during the Health Examination Survey. Significant negative correlations between the initial level and the subsequent changes in blood pressure were observed. The multiple regression analyses showed that the major determinants of systolic blood pressure (SBP) change were change in weight, baseline SBP, and baseline upper arm girth. Race, time interval between examinations, baseline age, and height change were also significant determinants in SBP change. For the change in diastolic blood pressure (DBP), baseline DBP, baseline weight, and weight change were the major determinants. Baseline SBP, time interval and race were also significant determinants. Sexual maturation variables were also considered in the subgroup analysis for girls. Weight change was the most important predictor of the change in SBP for the group of girls who were still in the pre-menarchal or pre-breast maturation status at the time of the follow-up examination, and who had started to menstruate or to develop breast maturation at sometime between the two examinations. Baseline triceps skinfold thickness or initial SBP were more important variables than weight change for the group of girls who had already experienced menarche or breast maturation at the time of the initial survey. For the total group, pubic hair maturation was found to be a significant predictor of SBP change at the 5% significance level. The importance of weight change and baseline weight for the changes in blood pressure warrants further study. ^

Assessing Temperament as a Predictor of Distress at Anesthesia Induction Using the Children’s Behavior Questionnaire Short Form

Thesis (Master's)--University of Washington, 2016-06

Race against time: The export of essential medicines to Rwanda

This article considers the significance of the first export of essential medicines under the WTO General Council Decision 2003. In July 2007, Rwanda became the first country to provide a notification under the WTO General Council Decision 2003 of its intent to import a fixed-dose, triple combination HIV/AIDS drug manufactured by the Canadian generic pharmaceuticalmanufacturer Apotex, Inc. In September 2007, Apotex was granted the first compulsory licence application under Canada's Access to Medicines Regime. This article considers the convoluted and protracted negotiations between the Government of Rwanda, Apotex and three patent holders, GlaxoSmithKline, Boehringer Ingleheim Canada and Shire BioChemical, Inc. It questions the efficiency of this process. This article considers the review of the Jean Chretien Pledge to Africa Act 2004 (Canada). It is critical of the refusal of the Conservative Government of Canada to make any amendments to the legislation to improve the cost-effective delivery of essential medicines. This article queries the proposed Hong Kong Amendment to the TRIPS Agreement 1994, given the concerns of the Africa Group. It is submitted that it is undesirable to codify the WTO General Council Decision 2003, given its failure to provide a speedy, efficient and cost-effective delivery of essential medicines.

Library of universal history and popular science; containing a record of the human race from the earliest historical period to the present time; embracing a general survey of the progress of mankind in national and social life, civil government, religion, literature, science and art ...

Issued under various titles.