[Plasma catecholamines, metabolic substrates, aerobic and anaerobic capacity during graduated treadmill and bicycle ergometer exercise (author's transl)]

Abstract

Adrenaline, noradrenaline, glucose, lactate, free fatty acids, and glycerine in blood, as well as heart frequency and oxygen intake were examined in 6 healthy male subjects (28 +/- 2.6 years) before, during and after a graduated treadmill (TME) and bicycle ergometer (BE) test. Adrenaline, noradrenaline, the energy supplying substrates, and the oxygen-intake show no differences during TME and BE at given submaximal levels. Noradrenaline is 27% (0.10 less than p less than 0.05) higher, pulse rate is 6% (p less than 0.05) lower, oxygen intake 4% (greater than 0.05) lower, and the glycerine level 25% (0.10 less than p less than 0.05) lower during maximal BE exercise. The tendency toward a higher noradrenaline release during BE exercise can be influenced by a greater static-pressure stress opposed to a dynamic-circulatory stress during TME testing. An increased alphareceptor stimulation leads to a negative chronotropic effect, whose cause is assumed to be a baroreceptor stimulation. The TME induces a higher circulation and a more economic oxygen supplying of the muscles exercised, as well as a favourable fat oxidation, which is recognizable by a more rapid increase of glycerine (0.10 less than p less than 0.05). When referring to exercise acidification (a tendency toward a lower lactate production during submaximal TME testing shows here), oxygen intake capability, energy supplying substrates, and the catecholamines, both forms of ergometer testing are comparable one to another; a falsification appears only when plasma catecholamines and lactate levels are based on the heart frequency, as it is influenced by the form of exercise.