[Plasma catecholamines, metabolic substrates, aerobic and anaerobic capacity during exercise in supine and sitting position (author's transl)]

[Conjugated plasma catecholamines are lower in power athletes at rest and in physical work than in untrained probands]

Lower levels of free plasma catecholamines, noradrenaline and adrenaline were recently described in statically trained athletes under identical work loads during incremental cycling as compared with untrained control subjects. These differences point to a control of sympathetic activity by static training. Theme of the presented investigation is the question of additional training-dependent alterations of the conjugated plasma catecholamines in statically trained athletes. Eight competition weight lifters (21 +/- 2 years of age; 73 +/- 10 kg body weight) and seven untrained healthy control subjects (26 +/- 6 years; 75 +/- 4 kg) were investigated. The conjugated catecholamines were radioenzymatically determined as the difference between total and free catecholamines. The investigated subjects performed an incremental, exhaustive bicycle ergometric test in an upright body position. Before exercise, the levels of conjugated plasma dopamine (P less than 0.10), of conjugated noradrenaline (P less than 0.001) and conjugated adrenaline (P less than 0.10) are 2-3 times lower in statically trained athletes than those of the control subjects. The conjugated catecholamines did not show any significant changes during exercise, the significant differences between both groups (P less than 0.05-P less than 0.01) were therefore also observed during exercise. In contrast to the free plasma catecholamine responses, the conjugated catecholamine fractions are seen as indicators of long term alterations of the sympathetic activity.

[Plasma dopamine, noradrenaline and adrenaline response during cardiac and peripheral-muscular exhaustion]

Nine healthy subjects performed 2 different graded bicycle ergometric tests. The 1st test started with 50 watt and was increased 50 watt after 3 min till exhaustion as a model of a metabolic and cardiac exhaustion. The 2nd test started with 100 watt and was increased 50 watt after 15 min till exhaustion as a model of a peripheral-muscular exhaustion. The behaviour of plasma catecholamines, lactate and glucose levels, heart rate and oxygen intake was examined. The results were as following: Performance ability 305 (test 1) and 233 watt (test 2; mean values), work time 17.5 min (1) and 51 min (2), heart rate 185 min-1 (1) and 175 min-1 (2), noradrenaline 30.7 nmol/l (1) and 11.0 nmol/l (2), adrenaline 6.9 nmol/l (1) and 2 nmol/l (2), lactate 9.2 (1) and 6.6 mmol/l (2), glucose 5.6 mmol/l (1) and 4.7 mmol/l (2). During highly intensive dynamic exercise (test 1), three times higher catecholamine and 50% higher lactate responses were observed, than during peripheral-muscular limited endurance exercise (test 2). Above an exercise level of more than 30% VO2 max., nor- and adrenaline increased significantly. Below 50-70% VO2 max. steady-state-behaviour occurred. Above this range unsteady-state-behaviour of plasma catecholamines was observed. Dopamine did not show any significant time and intensity dependent increase. Noradrenaline and adrenaline followed the same initial 1st order elimination kinetic.

[Behavior of free catecholamines in blood and urine of ambulance men and physicians during quick responses]

Free urine adrenaline, noradrenaline, (additional free plasma catecholamines in the physicians), and blood lactate were determined in 11 ambulance men and 5 physicians to assess stress during medical service. Stress was evaluated employing a stress index, based on difficulties in driving, traffic, severity of injuries or illness. Emergency cases with seriously injured subjects or reanimation were judged to have a 4-fold higher stress index than routine cases where strong physiological or psychological stress was absent. Urine catecholamines and stress indices were estimated in 3-h intervals. The calculations were based on the stress induced catecholamine concentrations minus the basal excretion during the same 3-h interval. Urine adrenaline and noradrenaline in ambulance men and physicians correlated directly with the stress index, as well as the plasma catecholamines of the physicians. Lactate levels showed similar behaviour and a descriptive direct correlation with the plasma catecholamines. Urine adrenaline increased more--dependent on the stress index--than urine noradrenaline. This over-proportional adrenaline response may be an indicator for the additional psychological stress in emergency cases. Therefore physicians showed--based on the same stress index--a tendency to higher urine adrenaline excretion and blood lactate levels than the ambulance men, which might be the consequence of the overall responsibility of the physicians. Because of the observed catecholamine responses during medical service, coronary insufficiency or hypertension might be contra-indications for participation in the medical service; regular clinical investigations including ergometric tests are advisable.

[Catecholamines, Cardiocirculatory, and Metabolic Response During Graduated and Continuously Increasing Exercise]

Adrenaline, noradrenaline, glucose, glycerol and the free fatty acids (FFA) in the blood, as well as the heart rate and oxygen intake, were tested in six healthy male volunteers (age: 28 +/- 6 years) during graduated (I) and continuously (II) increasing bicycle ergometric exercise (upright body position). The maximum heart rate, the VO2 max, the maximum lactate and FFA concentration show no significant difference, whereas adrenaline, noradrenaline and the glucose levels are significantly lower, and the glycerol concentration is slightly higher during the maximum test II as compared with test I. At some submaximum exercise levels, the lactate concentration and the heart rate are slightly lower, adrenaline and noradrenaline are significantly lower during test II; the FFA, glycerol and the oxygen intake do not show any significant difference. The duration of exercise was similar in both tests. The total work was about 50% lower in test II, and the maximum performance was slightly higher as compared with test I. These results could have significance for the planning of working conditions, the rehabilitation of patients, and the organisation of training for athletes.

[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.