title: Does exercise intensity affect blood pressure and heart rate in obese adolescents? A 6-month multidisciplinary randomized intervention study.
abstract: BACKGROUND
  Aerobic exercise improves cardiovascular health in general, but whether the impact varies with exercise intensity is not clear.
  
  
  OBJECTIVE
  The aim of the current study was to compare the effects of a high-intensity aerobic exercise training (HIT) vs. a low-intensity aerobic exercise training (LIT) on blood pressure (BP), heart rate (HR) and heart rate variability (HRV) in obese adolescents.
  
  
  METHODS
  Forty-three (13-18 years) Tanner stage (III-IV) matched obese adolescents were studied in a randomized trial of either HIT (corresponding to the ventilatory threshold I; n = 20) or LIT (corresponding to 20% below the ventilatory threshold I; n = 23) programme for a period of 6 months. All participants also received a multidisciplinary therapy that included nutritional, psychological and clinical counselling. Both HIT and LIT sessions were isocaloric, with energy expenditure set at 350 kcal. BP, HR and HRV were measured along with markers of body adiposity and insulin resistance before and after the respective interventions.
  
  
  RESULTS
  The participants in both groups had similar physical and clinical characteristics. After the 6-month intervention, systolic, diastolic and mean BP decreased (P < 0.05, for all) similarly in both groups, whereas waist circumference, HR and HRV showed beneficial changes only in the HIT group (P < 0.05).
  
  
  CONCLUSIONS
  Aerobic exercise training set at a high intensity compared with the low intensity appears to have additional benefits on abdominal obesity and cardiovascular health in that it enhances the parasympathetic and autonomic modulation of the heart in obese adolescents.
authors: School of Physical Education, University of Pernambuco, Recife, Pernambuco, Brazil.
authors: B Q
authors: BQ
authors: Farah
authors: R M
authors: RM
authors: Ritti-Dias
authors: P B
authors: PB
authors: Balagopal
authors: J O
authors: JO
authors: Hill
authors: W L
authors: WL
authors: Prado
mesh_terms: D000293:Adolescent; D001794:Blood Pressure; D001938:Brazil / Q000453:epidemiology; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D004734:Energy Metabolism; D015444:Exercise; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D009765:Obesity / Q000150:complications* / Q000453:epidemiology / Q000503:physiopathology; D005082:Physical Exertion; D010809:Physical Fitness; D011627:Puberty; D013997:Time Factors; D016896:Treatment Outcome
keywords: Adolescent; cardiovascular system; exercise; obesity