EXERCISE TRAINING IN AGING - HEMODYNAMIC, METABOLIC, AND OXIDATIVE STRESS EVALUATIONS

The effects of exercise training on hemodynamic and metabolic paramete rs as well as on responses to oxidative stress in aged individuals are controversial. The aim of the present study was to investigate change s in heart hate, mean arterial pressure, vasoreactivity, and plasma le vels of insulin and glucose in male aged Wistar rats submitted to exer cise training for 11 weeks (1 hid; 5 d/wk) in a treadmill. The isolate d heart was perfused by H2O2, and oxidative stress was evaluated using thiobarbituric acid reactive substances. Cardiovascular functions wer e recorded with a data acquisition system (CODAS, 1 kHz). Trained aged rats were bradycardic as compared with sedentary aged rats (298+/-7 v ersus 336+/-16 bpm) but presented similar mean arterial pressure and v asoreactivity and plasma levels of insulin and of glucose, which were quantified by radioimmunoassay and colorimetric enzymatic lest. Plasma levels of insulin and of glucose ratio were increased in trained aged rats (6.9+/-0.7 versus 3.5+/-0.4 in sedentary aged rats), and the res ponse to oxidative stress was decreased (0.4+/-0.1 versus 0.7+/-0,1 nm ol/mg protein in sedentary aged rats). These results showed that exerc ise training produced a lower resting heart rate as well as changes in metabolic and oxidative responses. This suggests a higher myocardium protection of trained than sedentary aged rats.