Time and frequency domain indices of heart rate variability in athletes and control subjects
| Athletes (n = 12) | Controls (n = 10) | p Value2-150 | |
|---|---|---|---|
| Time domain | |||
| MeanNN (ms) | 1244 (148) | 1085 (90) | 0.006 |
| SDNN (ms) | 101 (28) | 70 (18) | 0.007 |
| CVNN (%) | 8.1 (2.1) | 6.5 (1.5) | 0.042 |
| SDANN (ms) | 68 (12) | 61 (18) | NS |
| RMSSD (ms) | 71 (39) | 49 (19) | NS |
| pNN50 (%) | 41 (24) | 30 (17) | NS |
| Frequency domain | |||
| ln (LF) (ms2) | 7.42 (0.51) | 7.08 (0.54) | NS |
| ln (HF) (ms2) | 6.67 (0.93) | 6.41 (0.76) | NS |
| ln (LF/HF) | 0.75 (0.63) | 0.68 (0.49) | NS |
Values are mean (SD). ln, natural logarithm; CVNN, coefficient of variation; HF, high frequency power (>0.15–0.4 Hz); LF, low frequency power (0.04–0.15 Hz); LF/HF, ratio of low frequency and high frequency power; meanNN, mean of all RR intervals between normal beats; pNN50, percentage of successive RR intervals differing more than 50 ms; RMSSD, the root mean square of successive RR differences; SDANN, SD of the mean of RR intervals in all 5 minute segments; SDNN, SD of these RR intervals.
↵2-150 p Value of Student’s t test or Mann–Whitney test, as appropriate.