BACKGROUNDS. Heart rate variability increases with increased vagal effect. Compared to sedentary individuals, athletes have an increased vagal tone. Their resting heart rate decreases and heart rate variability increases. The aim of the study was to determine whether heart rate variability correlates with maximal aerobic capacity in a random population of athletes, and to establish any differences in heart rate variability between male and female athletes.
METHODS. The study included a sample of 63 athletes of both genders from different sporting disciplines. After recording a 10-minute ECG at rest in the supine position, they underwent a continuous graded stress test on a treadmill to determine their maximal aerobic capacity. The heart rate variability components and their relationships were then compared to maximal aerobic capacity. In order to determine the differences in heart rate variability between the high capacity and low capacity groups, and between the male and female groups, t-test for normally distributed and ANOVO test for non-normally distributed variables were used. The Pearson method for normally distributed variables and the Spearman method for non-nor- mally distributed variables were used to determine the correlation coefficients between heart rate variability and maximal aerobic capacity. The P-value of < 0.05 was considered statistically significant.
RESULTS. No significant differences were found in heart rate variability between the lower and higher maximal aerobic capacity groups or between the males and females. There was also no correlation between heart rate variability and maximal aerobic capacity in our group of athletes.
CONCLUSIONS. The connection between maximal aerobic capacity and heart rate variability in highly trained individuals is obviously not as direct as in the non-ath- letic population. According to the results of our study, the use of relation between heart rate variability and maximal aerobic capacity connection for training control is questionable.