Table 3.
Kinetics of cardiovascular parameters during the task.
| Variable | Control | P1 | P2 | P3 | P4 | p-value |
|---|---|---|---|---|---|---|
| Time domain | ||||||
| RRI (ms) | 747 (87) | 757 (106) | 772 (107) | 769 (107) | 773 (102) | 0.018 |
| STD RRI (ms) | 57 (27) | 39 (14) | 43 (14) | 49 (189) | 51 (21) | 0.000037 |
| HR (min-1) | 82 (9) | 81 (11) | 79 (11) | 80 (10) | 79 (10) | 0.012 |
| STD HR (min-1) | 6 (2) | 4 (1) | 5 (1) | 5 (1) | 5 (2) | 0.000013 |
| RMSSD (ms) | 20 (9) | 14 (6) | 16 (7) | 16 (8) | 18 (7) | 0.00019 |
| NN50 (count) | 13 (18) | 4 (10) | 6 (12) | 7 (19) | 6 (7) | 0.0032 |
| pNN50 (%) | 4 (5) | 1 (3) | 2 (3) | 2 (5) | 2 (2) | 0.0054 |
| RRI triangular index | 13 (4) | 9 (3) | 11 (4) | 11 (3) | 11 (3) | 0.00069 |
| TINN (ms) | 276 (127) | 188 (56) | 216 (75) | 226 (75) | 260 (97) | 0.0001 |
| Frequency domain | ||||||
| VLFcf (Hz) | 0.02 (0.01) | 0.01 (0.01) | 0.01 (0.01) | 0.01 (0.01) | 0.01 (0.01) | 0.25 |
| LFcf (Hz) | 0.07 (0.02) | 0.08 (0.03) | 0.08 (0.03) | 0.07 (0.03) | 0.08 (0.03) | 0.71 |
| HFcf (Hz) | 0.17 (0.01) | 0.17 (0.02) | 0.17 (0.01) | 0.17 (0.02) | 0.18 (0.03) | 0.29 |
| Total power (ms2) | 2989 (2587) | 1876 (1612) | 1824 (1527) | 2296 (1576) | 2740 (2183) | 0.029 |
| VLFpw (ms2) | 1697 (1675) | 1203 (1310) | 960 (1222) | 1415 (1183) | 1535 (1534) | 0.15 |
| LFpw (ms2) | 1105 (827) | 575 (381) | 750 (453) | 780 (519) | 1051 (848) | 0.025 |
| HFpw (ms2) | 186 (246) | 98 (115) | 115 (115) | 102 (125) | 154 (157) | 0.025 |
| VLFperc (%) | 53 (14) | 58 (16) | 47 (17) | 56 (20) | 52 (13) | 0.17 |
| LFperc (%) | 41 (13) | 36 (15) | 47 (16) | 40 (18) | 42 (13) | 0.16 |
| HFperc (%) | 6 (4) | 6 (4) | 6 (4) | 5 (4) | 6 (3) | 0.53 |
| LFnu (n.u.) | 88 (8) | 85 (9) | 87 (6) | 90 (6) | 88 (7) | 0.23 |
| HFnu (n.u.) | 12 (8) | 15 (9) | 13 (6) | 10 (6) | 12 (7) | 0.23 |
| LF/HF ratio | 10.5 (6.9) | 9.2 (6.7) | 10.8 (10.5) | 13.1 (10.0) | 11.4 (13.6) | 0.61 |
| Information domain | ||||||
| SD1 (ms) | 14 (6) | 10 (4) | 12 (5) | 12 (6) | 13 (5) | 0.00019 |
| SD2 (ms) | 79 (37) | 55 (19) | 59 (19) | 68 (26) | 70 (29) | 0.000042 |
| Mean line length (beats) | 13 (2) | 14 (2) | 14 (3) | 14 (3) | 15 (6) | 0.11 |
| Max line length (beats) | 365 (75) | 369 (71) | 364 (81) | 375 (51) | 340 (96) | 0.45 |
| REC (%) | 39 (5) | 41 (5) | 40 (6) | 41 (5) | 43 (10) | 0.2 |
| DET (%) | 99.51 (0.27) | 99.54 (0.25) | 99.50 (0.27) | 99.58 (0.22) | 99.57 (0.24) | 0.51 |
| Shannon entropy | 3.36 (0.16) | 3.41 (0.19) | 3.42 (0.21) | 3.47 (0.18) | 3.48 (0.31) | 0.25 |
| alpha 1 | 1.65 (0.12) | 1.59 (0.16) | 1.59 (0.17) | 1.64 (0.09) | 1.64 (0.13) | 0.18 |
| alpha 2 | 1.00 (0.14) | 0.99 (0.14) | 0.94 (0.18) | 0.98 (0.14) | 0.97 (0.14) | 0.56 |
| ApEn | 0.80 (0.09) | 0.84 (0.10) | 0.82 (0.09) | 0.79 (0.10) | 0.77 (0.12) | 0.033 |
| SampEn | 0.83 (0.14) | 0.88 (0.16) | 0.87 (0.14) | 0.80 (0.16) | 0.80 (0.21) | 0.074 |
| D2 | 2.21 (0.80) | 1.42 (0.85) | 1.76 (0.92) | 1.82 (0.81) | 1.96 (0.90) | 0.0002 |
| Hemodynamics | ||||||
| SBP (mmHg) | 114 (19) | 117 (14) | 109 (14) | 107 (17) | 104 (14) | 0.00051 |
| MBP (mmHg) | 87 (12) | 91 (9) | 84 (9) | 83 (10) | 82 (7) | 0.00031 |
| DBP (mmHg) | 71 (10) | 75 (8) | 69 (7) | 69 (10) | 70 (5) | 0.03 |
| DP (bpm⋅mmHg) | 8998 (1660) | 9197 (1509) | 8360 (1254) | 8334 (1488) | 8096 (1536) | 0.00012 |
| Baroreflex sensitivity (bpm⋅mmHg-1) | 15.3 (7.6) | 13.6 (6.6) | 13.7 (6.8) | 11.9 (7.0) | 13.9 (10.9) | 0.52 |
The kinetics of the cardiovascular parameters during the task are expressed as the mean (SD) throughout the protocol, i.e., during the Control condition and during the last 5 min of the first, second, third, and fourth temporal quartiles (P1, P2, P3, and P4, respectively). RRI, RR Intervals; STD RRI, standard deviation of RRI; HR, heart rate; STD HR, standard deviation of HR; RMSSD, root mean square of successive differences; NN50, number of successive RRI that differ more than 50 ms; pNN50, percentage of successive RRI that differ more than 50 ms; TINN, triangular interpolation of RRI histogram; VLF, very low frequency; LF, low frequency; HF, high frequency; cf, centroid frequency; pw, power; perc, percentage; nu, normalized units; SD1, standard deviation of the instantaneous beat-to-beat inter-beat interval variability (semi-minor axis length of Poincaré plot ellipse fitting); SD2, standard deviation of the long term beat-to-beat inter-beat interval variability (semi-major axis length of Poincaré plot ellipse fitting); REC, recurrence rate; DET, determinism; alpha 1, short-range scaling exponent; alpha 2, long-range scaling exponent; ApEn, approximate entropy; SamEn, sample entropy; D2, correlation dimension; SBP, systolic blood pressure; MBP, mean blood pressure; DBP, diastolic blood pressure; DP, double product. P-value of the ANOVA test for Period factor is reported as p-value in the last column.