Work-rest periods: their effects on normal physiologic response to isometric and dynamic work.
Heart rate (HR) and blood pressure (BP) responses to repeated dynamic and combined dynamic and isometric work bouts of 30 sec, 2 min, and 6 min with equal rest periods at 40% and 80% of Vo2max was studied in five healthy men and five healthy women. Total work duration for each experimental condition was 24 min. 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 Vo2max in 30 sec bouts compared to 6 min bouts reduced HR, BP and the double product (BP X HR) by 11%, 4%, and 14%, respectively. Work performed at 80% of Vo2max in 30 sec bouts of repeated work or rest compared to the 6 min 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.
D000328:Adult; D001481:Basal Metabolism; D001784:Blood Gas Analysis; D001794:Blood Pressure; D005080:Exercise Test; D005260:Female; D006339:Heart Rate; D006801:Humans; D007537:Isometric Contraction; D008297:Male; D010100:Oxygen / Q000502:physiology; D005082:Physical Exertion; D012146:Rest; D013997:Time Factors
D010100:Oxygen