Choice reaction time changes during a progressive exercise and its relation to heart rate and lactate threshold

The aim of this study was the examination of choice reaction time changes during a progressive exercise at different intensities and the relation of these intensities with heart rate (HR) and lactate threshold. 12 female students (19 - 32 yr.) from physical education faculty of Tehran University (Mvo2max=47.26) were selected. Subjects undertook a progressive exercise on treadmile. The first stage started with the speed of 4 m/ h and then increased 1 m/h every 2 min, until exhaustion. Subjects test choice reaction time (CRT) before and during the exercise every 30 sec. HR and respiratory gases data were recorded during the exercise. Data analysis indicated that CRT increased at the beginning of the exercise and then decreased to minimum level (70% vo2max) and then increased again until the end of the exercise. Also, CRT was never reached to its rest level and was approximately 8 percent more. There was no correlation between CRT scores and HR during exercise and at different work load (r=0.124). The optimal CRT was approximately at 170 b/m or about 86% maximum H R. In addition the work load related to minimum CRT was about 8 percent higher than the intensity related to lactate threshold.Conclusion: In spite of negative effect of dual task and physiological changes brought about exercise like lactic acid accumulation and HR, CRT and be improved but not under its rest level.