An Examination of Heart Rate Variability at Anaerobic Threshold and Respiratory Compensation Points During Cardiopulmonary Exercise Test

The aim of this study is to examine the changes in HRV values before, during (at AT and RC) and after maximal incremental cardiopulmonary exercise test. The sample comprised 121 healthy men who recreational do exercise 2-3 days a week. (age: 30.5 ± 4.6 years, height: 177.8 ± 6.1 cm; weight: 80.2 ± 10.2 kg). Anthropometric measurements were measured by using body analyzer, and aerobic capacities of participants were measured by using the cardiopulmonary exercise test via the Bruce protocol. According to this, heart rate variability recordings were taken at seven stages during the cardiopulmonary exercise test: before the test (1), at the beginning of the test (2), between the beginning of the test and the anaerobic threshold (3), at the anaerobic threshold (4), between the anaerobic threshold and the respiratory threshold (5), at the respiratory threshold (6), and finally (7), 30 seconds after the cardiopulmonary exercise test. Repeated measures analysis of variance (ANOVA) was used to compare the HRV values obtained from the test stages. In conclusion, using a gas analyzer during cardiovascular exercise testing, HRV values (MeanRR, SDNN, RMSSD, LFnu) determined at seven stages continue to decrease from the beginning. A rest period of 30 seconds (passive rest) immediately after completing the exercise does not seem to be sufficient for recovery. According to the results of this study, it can be considered that the sympathetic nervous system activity (LFnu) exhibits a more pronounced appearance at threshold zones.