title: Evidence of increased cardiac parasympathetic drive in subjects meeting current physical activity recommendations.
abstract: BACKGROUND
  Aerobic fitness seems to provide extra protection to the cardiovascular system beyond changing the traditional risk factors, a phenomenon referred to as the risk factor gap model. Aerobic fitness may possibly lead to improved autonomic regulation. The Task Force of the American Heart Association supports a national campaign to reach specific cardiovascular health goals considering various metrics, including recommended physical activity (PA) volumes. It may be clinically relevant to assess whether autonomic remodeling occurs in those who adhere to the PA recommendations.
  
  
  METHODS
  We studied 39 healthy subjects (22 males and 17 females), subdivided into two groups, according to whether they were meeting or not meeting PA recommendations (150 min/week of moderate aerobic activity, or 75 min/week of vigorous aerobic activity, or a combination of both). For each group, we evaluated aerobic capacity (VO2 Peak), body composition (Fat Mass) and autonomic nervous system profile, by way of mono and bivariate spectral analysis of cardiovascular beat by beat variability.
  
  
  RESULTS
  Subjects following PA recommendations show higher RR period, higher RR variance, greater absolute power of the respiratory component of RR variability (HFRR) and higher index alpha (a measure of spontaneous baroreflex). Moreover, as expected, the group that was meeting or exceeding current PA recommendations had higher VO2 peak, less fat mass and greater weekly energy expenditure.
  
  
  CONCLUSIONS
  Data show that subjects meeting current PA recommendations present a phenotype suggestive of enhanced parasympathetic drive to the SA node. This finding is compatible with the hypothesis that a more favorable autonomic profile is part of the mechanisms of the risk factor gap.
authors.affiliation: University of Milan, Milan, Italy.|Exercise Medicine Unit, Humanitas Clinical and Research Center, Via Alessandro Manzoni, 56, 20089, Rozzano, Milan, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Sala
authors.affiliation: Exercise Medicine Unit, Humanitas Clinical and Research Center, Via Alessandro Manzoni, 56, 20089, Rozzano, Milan, Italy.|Biometra Department, University of Milan, Milan, Italy.
authors.forename: Mara
authors.initials: M
authors.lastname: Malacarne
authors.affiliation: University of Milan, Milan, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Pagani
authors.affiliation: Exercise Medicine Unit, Humanitas Clinical and Research Center, Via Alessandro Manzoni, 56, 20089, Rozzano, Milan, Italy. daniela.lucini@unimi.it.|Biometra Department, University of Milan, Milan, Italy. daniela.lucini@unimi.it.
authors.forename: Daniela
authors.initials: D
authors.lastname: Lucini
mesh_terms: D000328:Adult; D017704:Baroreflex / Q000502:physiology; D004562:Electrocardiography / Q000379:methods; D015444:Exercise / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D010275:Parasympathetic Nervous System / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology*; D012849:Sinoatrial Node / Q000502:physiology*
keywords: Aerobic fitness; Autonomic nervous system; Cardiovascular prevention; Exercise medicine; Parasympathetic; RR variability