title: Impact of aging on central pressure wave reflection characteristics during exercise.
abstract: BACKGROUND
  Age is associated with increases in elastic artery stiffness and pulse wave velocity, which cause profound changes in arterial pressure waves, including increases in the augmentation index (AIx) and wasted left ventricular (LV) energy. We examined the impact of aging on the central blood pressure (BP) waveform and wave reflection responses during exercise.
  
  
  METHODS
  Central BP and wave reflection characteristics were measured non-invasively using radial artery applanation tonometry at rest and during cycling exercise (45-65% of age predicted maximal heart rate (HR)) in 16 older (48 +/- 2 years) and 14 younger (24 +/- 1 years) men.
  
  
  RESULTS
  Older men had increased central pressure values and AIx (26 +/- 2% vs. 12 +/- 2%) and lower pulse pressure amplification (PPA; 1.29 +/- 0.03 vs. 1.50 +/- 0.04) than their younger counterparts at rest (P < 0.05). Central pressure values and AIx (10 +/- 3% vs. -8 +/- 3%) continued to be greater, while PPA (1.61 +/- 0.04 vs. 1.85 +/- 0.03) was lower in the older group compared with the younger group during exercise (P < 0.05). However, the relative changes from baseline for central pressure values, AIx (-15 +/- 2 vs. -19 +/- 3), and PPA (0.32 +/- 0.03 vs. 0.35 +/- 0.04) were similar for both groups (P > 0.05).
  
  
  CONCLUSIONS
  The findings of this study suggest that older men have a greater central BP and AIx and lower PPA during exercise. However, the magnitude of the central hemodynamic responses (i.e., change from baseline) during exercise does not differ between older and younger men.
authors.affiliation: Center for Exercise Science, Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, Florida, USA. casey.darren@mayo.edu
authors.forename: Darren P
authors.initials: DP
authors.lastname: Casey
authors.forename: Wilmer W
authors.initials: WW
authors.lastname: Nichols
authors.forename: Randy W
authors.initials: RW
authors.lastname: Braith
mesh_terms: D000328:Adult; D000367:Age Factors; D000375:Aging / Q000502:physiology*; D001011:Aorta / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology*; D001916:Brachial Artery / Q000502:physiology; D002318:Cardiovascular Diseases / Q000175:diagnosis / Q000503:physiopathology; D004562:Electrocardiography; D015444:Exercise / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012016:Reference Values; D012307:Risk Factors; D013318:Stroke Volume / Q000502:physiology*