Effects of detraining on cardiorespiratory and metabolic responses after six weeks high-intensity cycling

Abstract

This study evaluated novel submaxiJllal indicators of cardio-respiratory fitness during high constant-load (HCL) exercise tests in response to detraining. A central variable was the slow component YO') (SC); SC is defined as the difference between end-exercise YO:: and 3-min V02 (Gaesser et a1. ESSR, 1996). Ternlinal heart rate (HR) and blood lactate (HLa) were taken at the end of HCL tests. Ten sedentary males (18-30 yr) were screened and gave informed consent. Subjects cOInpleted a maximal and HCL exercise test for baseline assessment. The maxima] test variables, va:: peak and lactate threshold (LT), were used to set loads for the HCL tests and the training protoco1. Cycle ergometer training was done - 30 min/day, 5 days/week for 6 weeks at . 70(L T - V02peak ). Subjects were tested at week six of training and then detrained for two weeks. HCL tests were repeated at one and two weeks of detraining and an additional maximal test was performed after week two. Significant differences (p<O.OO 1) were found in terminal heart rate following one and two weeks of detraining compared to post-training values, with increases of 6.20/0 and 5%, respectively. No significant changes occurred for SC and HLa. While terminal heart rate is known to exhibit a rapid time course change in detraining, SC and HLa need to be studied for a longer detraining period.