PubMed1975
The main factors studied were the overall energy output and, in particular, the effects on the respiratory, cardiac and circulatory systems. The basic result was to demonstrate that while driving there occur more or less marked physiological modifications to these systems, which can be determined as to quantity; it seems clear that during particularly difficult conditions at the wheel or in subjects whose health is less than perfect, this can go as far as pathological situations. The values of catecholamines and their metabolites in the blood and urine were chosen as evaluation parameters. Catecholamines--that is, adrenaline, noradrenaline and dopamine--are substances produced by the adrenal glands; they play an essential part in the "functioning" of the sympathetic nervous system (which has important tasks, such as that of regulating the organism's equilibrium especially in reactions to sudden events or emergency situations) and are a reliable indication of effort and stress. Their action is seen in stimulation of the nervous system, cardiac agitation, an increase in blood pressure and in the production of lactic acid, increases in the basal metabolism, and so on. An excessive amount of these substances in the blood can cause real damage, above all to the heart and brain, especially in organs already affected in some way. The subjects studied were healthy volunteers, ranging in age between 20 and 35 and of comparable height and weight. A sort of "cross-over" experiment was carried out, so that the same subject was first studied driving with one type of gear change and then, two days later, was studied in the same experimental conditions but driving a vehicle with the other type of gear change. Analysis of the blood and urine sample was carried out in "single blind-test" conditions, in the sense that the research worker did not know where the samples came from. The biochemical analyses of the blood were: 1) Gas-analysis; 2) Hemochrome; 3)LDH-SGOT-Alkaline phosphatase; 4)Noradrenaline; 5)Cortisol. The following urine analyses were made: 1)Total catecholamines; 2)Vanillylmandelic acid. Clinical tests included: 1. Measurement of arterial pressure, at the beginning, at the end and during the driving period at the 30th and 90th minute. 2. Measurement of cardiac frequency,at the beginning, at the end and during the driving period at the same times. Blood pressure was measured by the auscultatory method, using an armband apparatus with aneroid capsule; cardiac frequency was measured at the wrist using the simple palpatory method, per 60 seconds.