title: Baroreflex function in sedentary and endurance-trained elderly people.
abstract: OBJECTIVE
  to determine the differences associated with age and endurance exercise training on the baroreflex function of healthy subjects.
  
  
  METHODS
  cross-sectional study.
  
  
  METHODS
  university research department.
  
  
  METHODS
  26 (10 female) sedentary, healthy, normotensive elderly subjects (mean age 67 years, range 62-81), eight (two female) elderly endurance-trained athletes (66 years, 62-69) and eight (two female) young (30 years, 25-34) subjects.
  
  
  METHODS
  baroreflex sensitivity was quantified by the alpha-index, at high frequency (HF, 0.15-0.35 Hz) and mid frequency (MF, 0.05-0.15 Hz), derived from spectral and cross-spectral analysis of spontaneous fluctuations in heart rate and blood pressure.
  
  
  RESULTS
  resting heart rate was significantly lower in endurance-trained athletes than sedentary elderly people (58 +/- 12 versus 68 +/- 11 min(-1), P < 0.05) but not different to that in healthy young subjects (63 +/- 9 min[-1]). alpha(HF) in sedentary elderly subjects (8.1 +/- 4.2 ms.mm Hg[-1]) was lower than both endurance-trained elderly athletes (14.8 +/- 4.8 ms.mm Hg(-1), P < 0.05) and healthy young subjects (28.3 +/- 21.8 ms.mm Hg(-1), P < 0.05) and was not significantly different between endurance-trained elderly athletes and healthy young subjects (P = 0.10). alpha(MF) in healthy young subjects (15.4 +/- 8.8 ms.mm Hg[-1]) was greater than in sedentary elderly subjects (6.5 +/- 3.2 ms.mm Hg(-1), P < 0.01) and endurance-trained elderly athletes (6.9 +/- 2.0 ms.mmHg(-1), P < 0.01), while there was no significant difference between the two elderly groups (P = 0.66).
  
  
  CONCLUSIONS
  both components of the baroreflex measured by the alpha-index show a decrease with age. Elderly endurance-trained athletes have less reduction in the high, but not mid, frequency component of the alpha-index compared with sedentary elderly subjects. Some of the age-related changes in baroreflex sensitivity may be related to physical fitness and activity levels.
authors.affiliation: Department of Pharmacological Sciences, The University, Newcastle upon Tyne, UK.
authors.forename: A J
authors.initials: AJ
authors.lastname: Bowman
authors.forename: R H
authors.initials: RH
authors.lastname: Clayton
authors.forename: A
authors.initials: A
authors.lastname: Murray
authors.forename: J W
authors.initials: JW
authors.lastname: Reed
authors.forename: M F
authors.initials: MF
authors.lastname: Subhan
authors.forename: G A
authors.initials: GA
authors.lastname: Ford
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017704:Baroreflex / Q000502:physiology*; D015924:Blood Pressure Monitors; D003430:Cross-Sectional Studies; D004562:Electrocardiography; D005260:Female; D015577:Geriatric Assessment; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010806:Physical Education and Training; D010807:Physical Endurance / Q000502:physiology*; D012016:Reference Values; D012815:Signal Processing, Computer-Assisted