Purpose: Aging is associated with increased oxidative stress, whereas systematic exercise training has been shown to improve quality of life and functional performance of the aged. This study aimed to evaluate responses of selected markers of oxidative stress and antioxidant status in inactive older men during endurance training and detraining.
Methods: Nineteen older men (65–78 yr) were randomly assigned into either a control (C, N = 8) or an endurance-training (ET, N = 11, three training sessions per week, 16 wk, walking/jogging at 50–80% of HRmax) group. Before, immediately posttraining, and after 4 months of detraining, subjects performed a progressive diagnostic treadmill test to exhaustion (GXT). Plasma samples, collected before and immediately post-GXT, were analyzed for malondialdehyde (MDA) and 3-nitrotyrosine (3-NT) levels, total antioxidant capacity (TAC), and glutathione peroxidase activity (GPX).
Results: ET caused a 40% increase in running time and a 20% increase in maximal oxygen consumption (V̇O2max) (P < 0.05). ET lowered MDA (9% at rest, P < 0.01; and 16% postexercise, P < 0.05) and 3-NT levels (20% postexercise, P < 0.05), whereas it increased TAC (6% at rest, P < 0.01; and 14% postexercise, P < 0.05) and GPX (12% postexercise, P < 0.05). However, detraining abolished these adaptations.
Conclusions: ET may attenuate basal and exercise-induced lipid peroxidation and increase protection against oxidative stress by increasing TAC and GPX activity. However, training cessation may reverse these training-induced adaptations.
1Democritus University of Thrace, Department of Physical Education and Sport Science, Komotini, GREECE; 2University of Thessaly, Department of Physical Education and Sports Sciences, Trikala, GREECE; and 3University of Athens, Medical School, Department of Experimental Physiology, Athens, GREECE
Address for correspondence: Ioannis G. Fatouros, Dept. of Physical Education & Sport Science, 7th km of National Rd. Komotini-Xanthi, Komotini, 69100, Greece; E-mail: firstname.lastname@example.org.
Submitted for publication March 2004.
Accepted for publication July 2004.