Cardiac autonomic regulation after continuous and intermittent maximal exercise interventions.

AIM: The aim of this study was to assess relationships between cardiac autonomic regulation after exercise and different types of single-bout exercise of a maximal intensity and of a similar duration. METHODS: The study group consisted of 30 males (23 ± 2 year old), which was separated into three subgroups. Groups A and B performed exercise interventions (continuous or intermittent), while group C represented the control group. Heart rate variability (HRV) was monitored continuously over 30 min after the exercise and consequently during a 6 h period following intervention. Spectral analysis parameters of HRV (total [PT], low- [PLF], high- [PHF] frequency power, LF/HF, and PLF in normalized units [LFnu]) were determined over 5 min intervals. Heart rate recovery (HRR) was also analysed. RESULTS: There were not significant differences between groups A and B for the entire HRV monitoring (P<0.05) or in the relatively expressed HRR. The cardiac autonomic modulation expressed by PT, PLF, and PHF fully recovered in 120 min after exercise, whereas LF/HF and LFnu did not significantly differ (P<0.05) from the control group 60 min earlier. CONCLUSION: Cardiac autonomic recovery after all-out exercise is type non-dependent and sympathovagal balance restores faster than the absolute HRV magnitude.

IL-6 and CRP response to maximal exercise intervention.

AIM: The purpose of this study was to investigate the recovery pattern of the plasma inflammatory markers interleukin-6 (IL-6) and C-reactive protein (CRP) after the single-bout maximal exercise. The exercise of different type (continuous vs. intermittent) was performed and also compared in this study. METHODS: Following baseline testing, 30 males were divided into three experimental groups, which completed continuous or intermittent all-out exercise of similar duration or no exercise intervention (Control group). Blood was sampled before and 1 h, 3 h, 5 h after exercise. Serum was analysed for IL-6, CRP, lactate, creatinine, uric acid, cortisol, creatine kinase, lactate dehydrogenase and myoglobin. Diet was standardized during recovery monitoring. RESULTS: Serum IL-6 and CRP concentrations were not significantly changed in the pre- to post-exercise values comparison. These results are evident in both exercise intervention groups as well as in the control group. The only exception is the significant (P=0.03) IL-6 decrease (28.2%) in continuous exercise protocol 3 h after the exercise. Significant changes (P<0.05) were also observed in lactate, cortisol, uric acid and myoglobin, when pre-exercise vs. post-exercise recovery values were compared CONCLUSION: The exercise of all-out intensity and relatively short duration, no matter what type, does not elicit a significant change in the inflammatory markers IL-6 and CRP for the 1h to 5h period of rest following the exercise.