Descriptive statistics of heart rate variability indices assessed 1 month after the race (baseline) and on site after the half marathon completion (postrace)
| Baseline | Postrace | |||
|---|---|---|---|---|
| Supine | Standing | Supine | Standing | |
| HR (bpm) | 63±12 | 74±16** | 86±14* | 97±16*,** |
| Resp (cycles/min) | 16±3 | 15±1 | 18±1* | 19±1* |
| RR (ms) | 993±183 | 842±168** | 730±127* | 643±110*,** |
| σ2RR (ms2) | 3874±788 | 3044±852 | 1567±586* | 1671±823* |
| LFRR (ms2) | 1026±113 | 1455±319 | 1001±448 | 1431±148 |
| LFRR (nu) | 59±12 | 81±16** | 76±13* | 86±10** |
| HFRR (ms2) | 646±130 | 357±45 | 132±97* | 178±88 |
| HFRR (nu) | 37±22 | 17±6** | 14±9* | 8±7*,** |
| LF/HR ratio | 3±3 | 15±4** | 11±2* | 34±4** |
Data represent mean±SD, *p<0.05 postrace versus baseline; **p<0.05 standing versus supine.
σ2RR, variance of RR variability; HFRR, high-frequency power of RR variability; HR, heart rate; LFRR, low-frequency power of RR variability; nu, normalised units; RR, R–R interval; Resp, respiratory activity.