Arterial wave reflection and vascular autonomic modulation in young and older men.
OBJECTIVE
Arterial stiffening with aging causes early return of reflected arterial pressure waves from peripheral arteries and augmentation of these waves on incident aortic pressure waves. The purpose of this study was to examine the relationship between pressure wave reflection and augmentation from peripheral arteries and peripheral sympathetic vasomotion in young and older men.


METHODS
Thirty males (15 young, 15 older) participated in this cross-sectional study. Radial artery applanation tonometry was used to derive aortic pressure wave reflection time (Deltat; index of aortic stiffness) and augmentation index (AIx; index of wave reflection intensity). Low frequency (LF) power attained from spectral decomposition of beat-to-beat systolic blood pressure (SBPLF) variability was used as an estimate of sympathetic vasomotor modulation.


RESULTS
SBPLF power was higher in older vs younger men (8.0+/-0.9 vs 4.5+/-0.5 mmHg2, p<0.05). Older men had higher AIx (24.0+/-1.8% vs -11.6+/-2.3%, p<0.05) and lower Deltat (138.1+/-1.9 ms vs 185.8+/-5.9 ms, p<0.05) compared with younger males. When ANCOVA was performed with SBPLF power as the covariate, the group differences in AIx75 and Deltat were preserved. Results from multiple regression revealed that, after entering age into the model, SBPLF power was not a significant correlate of AIx or Deltat, accounting for a non-significant 1.2% and 1.1% of the variance, respectively.


CONCLUSIONS
These findings suggest that increased blood pressure variability with aging is not related to age-associated increases in aortic stiffness or wave reflection.
Heffernan
Kevin S
KS
Exercise and Cardiovascular Research Laboratory, and the Exercise Immunology Laboratory, Department of Kinesiology and Community Health, University of Illinois at Urbana Champaign, Champaign, IL, USA. kheffer2@uiuc.edu
Jae
Sae Young
SY
Lee
Miyoung
M
Woods
Jeffrey A
JA
Fernhall
Bo
B
D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D001011:Aorta / Q000502:physiology*; D001341:Autonomic Nervous System / Q000502:physiology*; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology*; D001916:Brachial Artery / Q000502:physiology; D003430:Cross-Sectional Studies; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008365:Manometry; D017534:Radial Artery / Q000502:physiology*; D012039:Regional Blood Flow / Q000502:physiology; D012044:Regression Analysis