Biological indicators of stress in racing car drivers

To evaluate neuroendocrine and cardiovascular parameters of stress related to car racing, 24 healthy amateur drivers were studied both before and during a car race. For this purpose, we measured catecholamines and cortisol in urine and monitored the dynamic electrocardiogram (ECG). Urinary epinephrine (E) and norepinephrine (NE) increased significantly during the race, whereas dopamine (DA) remained unchanged and cortisol rose, but not significantly. Urinary excretion of E during the race increased in all drivers, and the increase was, on average, about fourfold that observed for NE and cortisol. A significantly lower NE/E ratio and significantly higher 10 E/DA and 10 NE/DA ratios were observed during racing. The percentage change in E excretion levels (from before to during the race) was positively related to anxiety scores. Continuous ECG Holter recordings in 6 out of the 24 volunteers showed heart rates of 76 to 152 beats/min over the 15 min before the start of the car race. During the race, heart rate reached a mean of 163.5±7.4 beats/min with a range of 146 to 180 beats/min. Except for sporadic ectopic beats, no significant arrhythmias, and S-T segment changes were observed in the electrocardiograms.