title: Aerobic exercise training can reverse age-related peripheral circulatory changes in healthy older men.
abstract: BACKGROUND
  The age-related decline in maximal oxygen consumption is attenuated by habitual aerobic exercise. However, the relative effects of training on central and peripheral responses to exercise in older subjects are not known. The present study assessed the contribution of central and peripheral responses to the age-associated decline in peak oxygen consumption and compared the effect of exercise training in healthy older and younger subjects.
  
  
  RESULTS
  Ten older and 13 younger men underwent invasive measurement of central and peripheral cardiovascular responses during an upright, staged cycle exercise test before and after a 3-month period of exercise training with cycle ergometry. At baseline, cardiac output and AV oxygen difference during exercise were significantly lower in older subjects. With training, the older and younger groups increased maximal oxygen consumption by 17.8% and 20.2%, respectively. Peak cardiac output was unchanged in both groups. Systemic AV oxygen difference increased 14.4% in the older group and 14.3% in the younger group and accounted for changes in peak oxygen consumption. Peak leg blood flow increased by 50% in older subjects, whereas the younger group showed no significant change. There was no change in peak leg oxygen extraction in the older group, but in the younger group, leg AV oxygen difference increased by 15.4%.
  
  
  CONCLUSIONS
  These findings suggest that the age-related decline in maximal oxygen consumption results from a reversible deconditioning effect on the distribution of cardiac output to exercising muscle and an age-related reduction in cardiac output reserve.
authors.affiliation: Department of Medicine, Divisions of Cardiology and Geriatrics, Center for the Study of Aging and Human Development, Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: P A
authors.initials: PA
authors.lastname: Beere
authors.forename: S D
authors.initials: SD
authors.lastname: Russell
authors.forename: M C
authors.initials: MC
authors.lastname: Morey
authors.forename: D W
authors.initials: DW
authors.lastname: Kitzman
authors.forename: M B
authors.initials: MB
authors.lastname: Higginbotham
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001775:Blood Circulation / Q000502:physiology*; D002302:Cardiac Output / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D007866:Leg / Q000098:blood supply; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption / Q000502:physiology; D010806:Physical Education and Training; D012016:Reference Values; D012039:Regional Blood Flow / Q000502:physiology
chemical_list: D010100:Oxygen