Exercise duration as a determinant of vascular function and antioxidant balance in patients with coronary artery disease.
Michaelides AP., Soulis D., Antoniades C., Antonopoulos AS., Miliou A., Ioakeimidis N., Chatzistamatiou E., Bakogiannis C., Marinou K., Liakos C., Stefanadis C.
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. DESIGN, SETTING, PATIENTS, INTERVENTIONS: 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.