title: Exercise duration as a determinant of vascular function and antioxidant balance in patients with coronary artery disease.
abstract: BACKGROUND
  Exercise improves the clinical outcome of patients with coronary artery disease (CAD); however, the ideal exercise duration for each patient remains unclear.
  
  
  OBJECTIVE
  To investigate the effects of exercise duration on arterial elastic properties and antioxidant/pro-oxidant mechanisms in patients with CAD.
  
  
  METHODS
  Sixty male patients with CAD were randomised into two groups, and underwent exercise for 30 min or 60 min in a crossover design with 2 weeks' wash-out period. In all participants aortic and radial blood pressures (BP) and arterial elastic properties (augmentation index (AIx)/pulse wave velocity (PWV)) were determined at baseline and 24 h after exercise. Plasma malonyldialdehyde (MDA) and superoxide dismutase (SOD)1 and SOD2 levels were also measured.
  
  
  RESULTS
  Exercise had no effect on aortic and radial BP (p=NS for all). Walking for 30 min improved AIx (from 33.79 ± 0.91% to 31.73 ± 0.86%, p<0.001) and PWV (from 9.26 ± 0.95 m/s to 9.06 ± 0.21 m/s, p<0.001), while exercise for 60 min had adverse effects on vascular stiffness (for AIx: from 33.37 ± 0.93% to 33.73 ± 1.05%, p=NS and for PWV: from 9.25 ± 0.19 m/s to 9.37 ± 0.21 m/s, p < 0.05 mainly in older patients). Exercise for 60 min was associated with a significant 20% increase in MDA levels (p<0.05). Exercise had no effects on SOD1 levels, however it significantly increased SOD2 levels after 30 min (from 2.26 ± 0.22 ng/mL to 2.36 ± 0.18 ng/mL, p < 0.05) but not after 60 min (p=NS). Conclusion Shorter exercise duration was associated with favourable antioxidant and vascular effects, while longer exercise blunted these beneficial effects and was accompanied by adverse effects on vascular function, mainly in older coronary patients. Further studies are required to explore the hypothesis that a more individualised approach to the selection of the appropriate exercise programme should be considered for patients with CAD.
authors.affiliation: Department of Cardiology, Athens University Medical School, Vrilissia, TK 15235, Athens, Greece. michaelides@freemail.gr
authors.forename: A P
authors.initials: AP
authors.lastname: Michaelides
authors.forename: D
authors.initials: D
authors.lastname: Soulis
authors.forename: C
authors.initials: C
authors.lastname: Antoniades
authors.forename: A S
authors.initials: AS
authors.lastname: Antonopoulos
authors.forename: A
authors.initials: A
authors.lastname: Miliou
authors.forename: N
authors.initials: N
authors.lastname: Ioakeimidis
authors.forename: E
authors.initials: E
authors.lastname: Chatzistamatiou
authors.forename: C
authors.initials: C
authors.lastname: Bakogiannis
authors.forename: K
authors.initials: K
authors.lastname: Marinou
authors.forename: C
authors.initials: C
authors.lastname: Liakos
authors.forename: C
authors.initials: C
authors.lastname: Stefanadis
mesh_terms: D000368:Aged; D000975:Antioxidants / Q000378:metabolism*; D001783:Blood Flow Velocity / Q000502:physiology; D003324:Coronary Artery Disease / Q000503:physiopathology* / Q000628:therapy; D018592:Cross-Over Studies; D004548:Elasticity / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005081:Exercise Therapy / Q000379:methods; D006801:Humans; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D008875:Middle Aged; D013482:Superoxide Dismutase / Q000378:metabolism; D000072105:Superoxide Dismutase-1; D014655:Vascular Resistance / Q000502:physiology; D016138:Walking / Q000502:physiology; D000099156:Superoxide Dismutase 2
chemical_list: D000975:Antioxidants; D008315:Malondialdehyde; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1; D000099156:Superoxide Dismutase 2; C000606290:SOD1 protein, human