[Catecholamine excretion during physical exercise and mental performance].

The basal and exercise-induced heart rates, lactate levels, and the adrenaline and noradrenaline excretions in the urine were measured during different types of physical exercise and mental performance: during moderate physical exercise (Ia, n = 12), submaximal physical exercise (Ib, n = 24), during moderate mental performance (motorway driving, IIa and IIb, n = 25), higher-grade mental performance (driving car-simulator, III, n = 14), and during submaximal mental performance (car racing, IV, n = 48). The moderate physical exercise and moderate mental performance could not be differentiated from one another, or from the higher-grade mental performance using the above-mentioned parameters. Both the submaximal physical exercise and mental performance resulted in a comparable lactate acidosis, heart rate increase, and noradrenaline excretion; the excretion of adrenaline is, however, 3 times higher after submaximal mental performance, than after submaximal physical exercise. The ratio of adrenaline to noradrenaline excretion changed from approximately 1:4 (during physical exercise and moderate mental performance) to approximately 1:2 during submaximal mental performance. The excretion of adrenaline and the ratio of adrenaline to noradrenaline excretion can therefore be used to differentiate between higher-grade mental performance and physical exercise. These parameters can be easily measured without discomfort to the subjects.