title: Association of age with timing and amplitude of reflected pressure waves during exercise in men.
abstract: BACKGROUND
  Increased elastic conduit artery stiffness with aging is associated with early wave reflection and increased wasted left ventricular pressure energy (LVE(W)). The effects of aging on central hemodynamics during exercise have not been well characterized. This study sought to investigate changes in central hemodynamics during cycle exercise in young, middle-aged, and older men.
  
  
  METHODS
  Central blood pressure and wave reflection characteristics were measured noninvasively using radial artery applanation tonometry at rest and during cycling exercise (45, 55, and 65% of predicted maximum heart rate (HR(max))) in 14 young (24 ± 1 years), 16 middle-aged (49 ± 2 years) and 13 older (73 ± 2 years) men.
  
  
  RESULTS
  Repeated measures analysis of variance revealed significant group-by-time interactions for heart rate, central diastolic blood pressure (DBP), central pulse pressure (PP), PP amplification (PPA), central aortic pressure augmentation (AP), aortic augmentation index (AI(X)), and LVE(W). Magnitude of change from baseline was significantly different in the older group compared to young and middle-aged groups in response to exercise at 65% of predicted HR(max) for AP (+3 ± 1 mm Hg vs. -7 ± 1, P < 0.001 and -3 ± 1 mm Hg, P < 0.001) and LVE(W) (+724 ± 215 dynes s/cm(2)·min vs. -494 ± 199, P < 0.001 and -315 ± 192, P < 0.001).
  
  
  CONCLUSIONS
  This study suggests that changes in the timing and amplitude of reflected pressure waves during exercise alter the hemodynamic response to exercise with aging. In response to exercise, AP and LVE(W) increased in older subjects while young and middle-aged subjects exhibited a decline in AP and no change in LVE(W).
authors.affiliation: Department of Applied Physiology and Kinesiology, Center for Exercise Science, College of Health and Human Performance, University of Florida, Gainesville, FL, USA. martin.jeff@hhp.ufl.edu
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Martin
authors.forename: Darren P
authors.initials: DP
authors.lastname: Casey
authors.forename: Alvaro N
authors.initials: AN
authors.lastname: Gurovich
authors.forename: Darren T
authors.initials: DT
authors.lastname: Beck
authors.forename: Randy W
authors.initials: RW
authors.lastname: Braith
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D001011:Aorta; D001794:Blood Pressure / Q000502:physiology*; D001916:Brachial Artery; D015444:Exercise / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged