Exercise training generates ascorbate free radical in rat heart.

Exercise generates free radicals and can cause damage to the tissues. This investigation shows the formation of ascorbate radicals during exercise training (ET) which reduce the toxicity of free radicals. Male Fischer-344 rats (n = 8) (77 weeks old) were given exercise training (ET) on a treadmill with a low intensity of exercise that gradually increased from the first to the ninth week resulting in an average increase in respiratory exchange ratio, oxygen consumption rate and heat production. The sedentary control (SC) rats (n = 8) were not exercised and maintained under the same conditions. The heart tissues from different SC and ET rats were analyzed for ascorbate free radical (Asc.-) using electron paramagnetic resonance (EPR). The heart tissue from the ET and not from the SC rat showed the presence of Asc.-. This Asc.- was characterized by an EPR spectrum which showed doublet with a hyperfine coupling constant of 1.89 Gauss (0.189 mT). The benefit of exercise could be attributed to the formation of ascorbate radical in the heart muscle of the old rat. Exercise training can provide protection to the heart tissue against oxidative damage via ascorbate ion and vitamin E.