Abstract
This study aimed to examine hemodynamic responses and the necessity of breaks under long working hours. Thirty-eight healthy males conducted PC-based work from 9:10 to 22:00. Nine 10-minute short breaks and two long breaks (a 1-hour break and a 50-minute break) were provided, and hemodynamic responses were measured regularly during this period. The results showed that systolic blood pressure increased during the working hours and cardiovascular burden increased under long working hours. Cardiac responses decreased, but vascular responses increased continually during work periods without long breaks. The long breaks, however, benefitted workers by preventing excessive decreases in cardiac responses and increases in vascular responses, but this effect may decrease with the extension of working hours. In conclusion, long working hours increase cardiovascular burden, and taking long breaks is important for reducing these burdens when long working hours cannot be avoided.