title: Higher systemic arterial compliance is associated with greater exercise time and lower blood pressure in a young older population.
abstract: OBJECTIVE
  Arterial compliance is an important therapeutic target in older individuals in whom stiffening of the proximal arterial circulation is thought to underlie systolic hypertension and increased cardiac work. We have shown previously that arterial compliance is related to aerobic fitness and that it is increased in young (20 to 35 years old), previously sedentary individuals by a 4-week period of moderate aerobic training. The extent to which compliance relates to exercise performance in a random selection of young older patients has not been reported previously. Therefore, we examined the interrelationship between systemic arterial compliance (SAC) and time to cessation of exercise during a standard treadmill exercise test in an older population.
  
  
  METHODS
  A cross-sectional survey.
  
  
  METHODS
  SAC was estimated at rest using simultaneous recordings of ascending aortic flow and carotid applanation tonometry in 43 subjects aged 67 +/- 7 years (mean +/- SD; 24 men and 19 women). Treadmill exercise testing was performed using a modified Bruce protocol. Aerobic capacity was assessed as Heart Rate-Blood Pressure product and exercise tolerance as total treadmill time.
  
  
  RESULTS
  SAC and exercise tolerance were related to gender, with men exhibiting greater exercise reserve and higher SAC than women. There was a significant positive correlation between SAC and time to cessation of exercise (r = .34; P = .03), with a negative correlation between SAC and resting heart rate-blood pressure product (r = -.66; P < .001). SAC was correlated with height and blood pressure. Exercise tolerance was related to height (P < .02).
  
  
  CONCLUSIONS
  These data indicate a positive association between SAC and fitness level in healthy older people and an inverse association between SAC and systolic blood pressure. Our findings are consistent with either (1) acquisition of a more compliant circulation and lower blood pressure through more physical activity or (2) that a more compliant arterial circulation and lower blood pressure permit greater athletic performance.
authors.affiliation: Department of Biomedical Engineering, La Trobe University, Melbourne, Australia. j.cameron@ee.latrobe.edu.au
authors.forename: J D
authors.initials: JD
authors.lastname: Cameron
authors.forename: C
authors.initials: C
authors.lastname: Rajkumar
authors.forename: B A
authors.initials: BA
authors.lastname: Kingwell
authors.forename: G L
authors.initials: GL
authors.lastname: Jennings
authors.forename: A M
authors.initials: AM
authors.lastname: Dart
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001158:Arteries / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology*; D003187:Compliance; D003430:Cross-Sectional Studies; D015444:Exercise / Q000502:physiology*; D017079:Exercise Tolerance / Q000502:physiology; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D011897:Random Allocation; D012727:Sex Characteristics; D013997:Time Factors; D018924:Vascular Capacitance / Q000502:physiology*