title: Aging, heart rate variability and patterns of autonomic regulation of the heart.
abstract: OBJECTIVE
  To evaluate the effects of aging, gender and body mass index on the heart rate variability (HRV), and to compare the patterns of global autonomic regulation (GAR) and parasympathetic outflow (PO) throughout the aging process.
  
  
  METHODS
  CROSS-SECTIONAL: Large sample of community-based adults and elderly people. Individuals aged from 40 to 100 years, functionally independent and with satisfactory cognitive function defined as the self-capacity to interact with an interviewer (N= 1743).
  
  
  METHODS
  The study enrolled individuals of both genders, stratified into five age-groups. We did adjustments for hypertension, dyslipidemia and non-insulin-dependent diabetes, as well as the body mass index (BMI). All groups undertook long-term electrocardiograms and five time-domain HRV parameters were measured, three (SDNN, SDANN, SDNN-index) reflecting the GAR and two (rMSSD and pNN50) the PO.
  
  
  RESULTS
  SDNN, SDANN and SDNN-index decreased linearly with age and BMI, and women had lower values than men (p<0.001). There was a U-shaped pattern of rMSSD and pNN50, with the nadir between 60 and 69 years for both genders, and women had higher values than men (p<0.001). The lowest levels of all HRV variables were found in diabetics (p<0.001). There was no influence of hypertension or dyslipidemia.
  
  
  CONCLUSIONS
  The GAR decreased linearly with the age in both genders. It is comparatively lower in women, diabetics and overweight individuals. The PO presented the U-shape in both genders with the nadir at the 7th decade. It was also comparatively lower in men and diabetics. Hypertension and dyslipidemia imparted no significant influence.
authors.affiliation: Division of Postgraduation in Health Sciences, Federal University of Sergipe, Aracaju, Sergipe, Brazil; Sao Lucas Foundation, Center of Researches, Aracaju, Sergipe, Brazil; Postgraduation in Health and Environment, Tiradentes University, Aracaju, Sergipe, Brazil. Electronic address: virtual.596@gmail.com.
authors.forename: Marcos Antonio
authors.initials: MA
authors.lastname: Almeida-Santos
authors.affiliation: Division of Postgraduation in Health Sciences, Federal University of Sergipe, Aracaju, Sergipe, Brazil; Sao Lucas Foundation, Center of Researches, Aracaju, Sergipe, Brazil.
authors.forename: Jose Augusto
authors.initials: JA
authors.lastname: Barreto-Filho
authors.affiliation: Division of Postgraduation in Health Sciences, Federal University of Sergipe, Aracaju, Sergipe, Brazil; Sao Lucas Foundation, Center of Researches, Aracaju, Sergipe, Brazil.
authors.forename: Joselina Luzia Menezes
authors.initials: JL
authors.lastname: Oliveira
authors.affiliation: Postgraduation in Health and Environment, Tiradentes University, Aracaju, Sergipe, Brazil.
authors.forename: Francisco Prado
authors.initials: FP
authors.lastname: Reis
authors.affiliation: Postgraduation in Health and Environment, Tiradentes University, Aracaju, Sergipe, Brazil.
authors.forename: Cristiane Costa
authors.initials: CC
authors.lastname: da Cunha Oliveira
authors.affiliation: Division of Postgraduation in Health Sciences, Federal University of Sergipe, Aracaju, Sergipe, Brazil; Sao Lucas Foundation, Center of Researches, Aracaju, Sergipe, Brazil.
authors.forename: Antonio Carlos Sobral
authors.initials: AC
authors.lastname: Sousa
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001341:Autonomic Nervous System / Q000503:physiopathology*; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D004562:Electrocardiography; D005260:Female; D006321:Heart; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012727:Sex Characteristics
keywords: Ambulatory electrocardiography; Autonomic nervous system; Health of the elderly; Heart rate variability