Regular exercise did not modify significantly superoxide dismutase activity in adolescents with Down's syndrome

Superoxide dismutase (SOD) overexpression in people with Down's syndrome negatively modifies the equilibrium SOD/glutathione peroxidase+catalase, which may ultimately lead to an increased hydroxyl radical formation.

To assess the influence of regular exercise on erythrocyte SOD activity to determine the ability of exercise to attenuate increased oxidative damage.

Thirty one male adolescents with Down's syndrome (mean (SD) age 16.3 (1.1) years) performed a 12 week training programme (three days a week), consisting of a warm up, exercise at a work intensity of 60-75% of peak heart rate (the latter calculated from 194.5 - (0.56 x age)), and a cool down period. The reduction of cytochrome c at 550 nm was used to monitor SOD activity in the supernatant of erythrocyte haemolysates.

Mean (SD) SOD activity in non-exercised adolescents with Down's syndrome was 679.0 (82) U/g haemoglobin (95% confidence interval 642.2 to 715.8). After the 12 week training programme, it had increased to 706.8 (91) U/g haemoglobin (95% confidence interval 663.9 to 749.8). This increase was not significant (p = 0.099).

Regular exercise did not significantly increase SOD activity and consequently did not affect the unbalanced equilibrium SOD/glutathione peroxidase+catalase observed in patients with Down's syndrome. Further studies are required to assess the behaviour of other antioxidant enzymes included in this pathway in order to highlight potential benefits of regular exercise in redox metabolism of patients with Down's syndrome.