title: Age and ethnicity differences in short-term heart-rate variability.
abstract: OBJECTIVE
  Hypertension is more frequent and more severe in older individuals and in African Americans. Differences in autonomic nervous system activity might contribute to these differences. Autonomic effects on the heart can be studied noninvasively through analysis of heart rate variability (HRV). We examined the effects of age and ethnicity on HRV.
  
  
  METHODS
  We studied 135 subjects (57 African Americans and 78 Caucasian Americans), aged 23 to 54 years. Using their surface electrocardiogram (ECG) data, we calculated the HRV indices with spectral analyses. High frequency (HF) power was used to index parasympathetic activity, whereas the ratio of low to high frequency power (LF/HF) was used to index sympathovagal balance.
  
  
  RESULTS
  Three HRV indices (HF, LF power, and LF/HF) were significantly related to age in Caucasian Americans but not in African Americans. The effect of age, ethnicity, and the age-by-ethnicity interaction on HF and LF power was significant, even after controlling for gender, body mass index, and blood pressure.
  
  
  CONCLUSIONS
  Young African Americans manifested a pattern of HRV response similarly to older Caucasian Americans. These results suggest that young African American individuals might show signs of premature aging in their autonomic nervous system.
authors.affiliation: Department of Neuropsychiatry, Kyunggi Provincial Hospital for the Elderly, Kyunggi-do, South Korea.
authors.forename: Jong-Bae
authors.initials: JB
authors.lastname: Choi
authors.forename: Suzi
authors.initials: S
authors.lastname: Hong
authors.forename: Richard
authors.initials: R
authors.lastname: Nelesen
authors.forename: Wayne A
authors.initials: WA
authors.lastname: Bardwell
authors.forename: Loki
authors.initials: L
authors.lastname: Natarajan
authors.forename: Christian
authors.initials: C
authors.lastname: Schubert
authors.forename: Joel E
authors.initials: JE
authors.lastname: Dimsdale
mesh_terms: D000328:Adult; D001741:Black or African American; D000367:Age Factors; D000375:Aging / Q000208:ethnology*; D019588:Aging, Premature / Q000208:ethnology* / Q000503:physiopathology; D001341:Autonomic Nervous System / Q000502:physiology / Q000503:physiopathology*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D044469:Racial Groups; D044465:White People