title: Cardiovascular autonomic function in healthy adolescents.
abstract: OBJECTIVE
  The purpose of this study was to determine effects of age, sex, race, body mass index, and Tanner's stage on short-term evoked cardiovascular autonomic tests (ie, Valsalva ratio and change in heart rate with deep breathing) and 24-hour heart rate variability (HRV) in a sample of healthy adolescents, as well as to identify normative indices of both short-term evoked and 24-hour HRV in this age group.
  
  
  METHODS
  A descriptive, correlational design was used.
  
  
  METHODS
  Study took place in a university hospital in a health science center located in the mid-South.
  
  
  METHODS
  Participants included 75 healthy adolescents: mean age was 15.0 +/- 1.6 years, 14 were African American, 61 were white, 49 were girls, and 26 were boys.
  
  
  METHODS
  Study measures included the Valsalva ratio, change in heart rate with deep breathing, and 24-hour HRV with power spectral analysis with Holter monitoring.
  
  
  RESULTS
  Major significant findings included lower values of 24-hour HRV measures for girls and African American adolescents (P <.05). Indices for normal ranges of both the short-term evoked and 24-hour HRV measures were computed with 95% confidence intervals.
  
  
  CONCLUSIONS
  Few published studies address cardiac autonomic function, including 24-hour HRV, in adolescents. Most studies reporting actual normative control values of HRV for youth typically have not addressed sex or racial differences. Our study included the largest number of adolescents to date in the reported literature and demonstrated the importance of considering sex and race variation in interpreting test results. The availability of state-of-the-art technology for obtaining HRV data allows for the early identification of subclinical cardiac autonomic changes in youth who have predispositions for cardiac complications, such as those with diabetes, congenital heart disease, or obesity.
authors.affiliation: Department of Maternal-Child Nursing, College of Nursing, University of Illinois, Chicago, IL 60612, USA.
authors.forename: Melissa Spezia
authors.initials: MS
authors.lastname: Faulkner
authors.forename: Donna
authors.initials: D
authors.lastname: Hathaway
authors.forename: Betsy
authors.initials: B
authors.lastname: Tolley
mesh_terms: D000293:Adolescent; D001341:Autonomic Nervous System / Q000502:physiology*; D015992:Body Mass Index; D016001:Confidence Intervals; D015716:Electrocardiography, Ambulatory; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D018709:Statistics, Nonparametric; D014636:Valsalva Maneuver