Abstract

Heart rate (HR) and blood pressure (BP) responses to repeated dynamic and combined dynamic and isometric work bouts of 30sec, 2min, and 6min with equal rest periods at 40 and 80 of V02max was studied in five healthy men and five healthy women. Total work duration for each experimental condition was 24min. The treadmill was used for dynamic work. Subjects pushed a bar horizontally while on the treadmill at 20 of their maximal voluntary strength for isometric work. Results showed that work performed at 40 of V02max in 30 sec bouts compared to 6min bouts reduced HR, BP and the double product (BP x HR) by 11, 4, and 14, respectively. Work performed at 80 of V02max in 30sec bouts of repeated work or rest compared to the 6min bouts resulted in reducing HR, BP, and double product 28, 15, and 39, respectively. Addition of the isometric load did not significantly change the results. This study suggests that cardiac patients may be able to perform more work safely if it is carried out in short periods alternating with rest periods of equal duration. Verf.-Referat