Presence of age- and sex-related differences in heart rate variability despite the maintenance of a suitable level of accelerometer-based physical activity

There is currently a lack of information adjacent on the influence of sex and age in heart rate variability (HRV), adjusted according to accelerometer-based physical activity (PADL). We hypothesized that the effect of sex and age on the HRV should be reduced or absent in individuals with a suitable PADL level. We aim to evaluate the influence of sex and age on HRV, adjusted for the confounding effects of the PADL level. A total of 485 age-stratified subjects (18-39, 40-59, and ≥60 years) underwent HRV analyses at rest and 7-day assessments of accelerometer-based PADL. Multivariate analyses of covariance were done using log-transformed HRV indices as outcomes, age and sex as fixed factors, and PADL, cardiovascular risk, fat body mass, and heart rate (HR) at rest as covariates. Despite the adjustment for directly measured PADL, women had better indices of vagal tone, whereas men had higher sympathetic influence. Also, compared to middle-aged and older adults, younger individuals (ages 18-39 years) presented better HRV. Multiple regression analyses confirmed that age and sex were the main predictors of HRV indices, even after adjusting for PADL directly assessed by triaxial accelerometer and HR. We also observed that the correlation between some HRV indexes and the different indexes of physical activity directly evaluated was significant, but not very consistent. Thus, HRV indices are influenced by age and sex, regardless of accelerometer-based physical activity. Interventions with physical activity and exercise aimed at improving the autonomic modulation of asymptomatic adults should take such differences into account.

A raça Gir Mocha na região Nordeste do Brasil: estrutura genética populacional via análise de pedigree / The Polled Gir Polled in Northeastern Brazil: population genetic structure via analysis of pedigree

Foram utilizados dados de pedigree de 2.558 bovinos da raça Gir Mocha nascidos no período de 1954 a 2005. As análises foram realizadas utilizando-se o programa Endog. Do total de animais estudados, 61,9%; 10,6% e 0,1% possuíam pedigree na primeira, segunda e terceira gerações, respectivamente.O número efetivo de rebanhos que forneceram machos reprodutores foi de 10,25 para pais e 3,87 para avôs, confirmando a baixa integralidade do pedigree. O número de animais fundadores foi de 975,5, e o número efetivo de fundadores de 141,34. O número de ancestrais na população referência foi de 924 animas, dos quais apenas 39 explicaram 50% da variabilidade genética da população.O coeficiente médio de relação foi estimado em 0,75%, sendo o maior coeficiente individual de 25%. O coeficiente de endogamia foi igual a zero de 1954 a 1984. Vale salientar que, neste período, estão incluídos os animais sem ascendência conhecida. A endogamia e o coeficiente médio de relação da população foram baixos, contudo podem estar subestimados em razão da pequena integralidade do pedigree.

In this study we used data from the 2558 pedigree cattle polled Gir born from 1954 to 2005. Analyses were performed using the Endog program. Of all animals studied, 61.86%, 10.56% and 0.10% had a pedigree in the first, second and third generation, respectively. The effective number of herds that provide breeding males was 10.25 for parents and 3.87 for grandparents, corroborating the low completeness of the pedigree. The number of founder animals was 975.5 and the effective number of founders were 141.34. The number of ancestors in the reference population was 924 animals from which only 39 accounted for 50% of the genetic variability of the population. The average relationship coefficient was estimated at 0.75%, the largest individual coefficient was 25%. The inbreeding coefficient was zero from 1954 to 1894. It is noteworthy that during this period included the population was low, but may be underestimated because of the small pedigree integrity.