Ventricular arrhythmias in healthy young men during physical exhaustion.

. The occurrence of ventricular arrhythmias was studied in 25 healthy young men, with the aid of ambulatory ECG monitoring, during maximal bicycle tests, short term running, exhausting route marches, and during a 16 h period after brief and long term exercise. The bicycle test allowed prediction of 4 out of the 12 cases (33%) with ventricular premature beats (VPB) during running. The bicycle test combined with ambulatory ECG monitoring over a 16 h period allowed prediction of 12 out of the 14 cases (86%) with VPBs during marching. All 9 subjects who became exhausted during marching had VPBs, whereas 5 out of the 16 who were not exhausted had VPBs (p < 0.001). In men with VPBs during all three exercise tests, the heart rates at the time of the VPBs were lowest during exhausting route marching. In conclusion, VPBs can be regarded as a physiological phenomenon if they occur only when exhaustion ensues.