[Effect of training on plasma levels of catecholamines on the course of submaximal exercise]

The effect of a 22.5 week training program on the fuel-hormone response to prolonged (1 h) high intensity (85% maximal aerobic power, MAP) of six male subjects was studied. The training program consisted of pedalling 1 h per day, four days a week, a bicycle ergometer at 80% of their MAP. It resulted in a 14.3% increase in Vo2 max (P less than 0.01). Training did not significantly alter the RQ neither the blood glucose and lipid values measured at the end of a 1 h exercise requiring 85% of Vo2 max. At the end of the exercise blood level of norepinephrine was unchanged; in contrast, that of epinephrine was significantly (35%; P less than 0.01) reduced at the end of training. These results lead to the conclusion that during high intensity submaximal exercise there is no consistent relationship between the epinephrine blood level and mobilization or metabolic utilization of energy substrates in trained subjects.