Table 1.
Arterial blood pressure, heart rate and MSNA during the resting period, at each level of exercise, and during the recovery periods
| Rest | Very mild | Mild | Moderate | Heavy | Exhausting | Rec1 | Rec2 | |
|---|---|---|---|---|---|---|---|---|
| SAP (mmHg) | 136 ± 3.1 | 156 ± 3.2* | 177 ± 4.7* | 187 ± 5.6* | 195 ± 7.3*† | 199 ± 10.4*† | 123 ± 5.6† | 121 ± 7.7† |
| DAP (mmHg) | 66 ± 1.9 | 65 ± 2.0 | 66 ± 2.8 | 69 ± 1.8 | 73 ± 2.3* | 75 ± 2.8*† | 58 ± 2.5*† | 64 ± 2.5 |
| MAP (mmHg) | 89 ± 1.8 | 95 ± 1.5* | 103 ± 2.7* | 109 ± 2.4* | 114 ± 3.2*† | 116 ± 4.4*† | 79 ± 3.6*† | 83 ± 4.3† |
| HR (beats min−1) | 74 ± 3.1 | 85 ± 3.3* | 108 ± 3.4* | 131 ± 5.6* | 160 ± 5.9*† | 179 ± 7.1*† | 129 ± 7.6*† | 114 ± 7.1*† |
| MSNA burst frequency (bursts min−1) | 26.3 ± 1.8 | 19.1 ± 1.8* | 24.6 ± 2.3 | 33.7 ± 3.6* | 46.2 ± 4.7*† | 66.0 ± 5.2*† | 55.6 ± 1.5*† | 54.1 ± 3.4*† |
| MSNA burst incidence (bursts 100 HR−1) | 35.3 ± 2.5 | 22.5 ± 2.0* | 22.8 ± 2.0* | 25.7 ± 2.8* | 29.3 ± 3.5 | 37.3 ± 3.0† | 43.7 ± 3.1*† | 48.4 ± 4.3*† |
| Mean burst strength (AU) | 117.9 ± 5.4 | 101.0 ± 4.4* | 115.8 ± 7.4 | 137.2 ± 9.5* | 172.0 ± 12.3*† | 220.8 ± 16.6*† | 180.9 ± 11.6*† | 169.6 ± 12.6*† |
| Total MSNA (AU) | 3128 ± 289 | 1877 ± 167* | 2882 ± 365 | 4671 ± 581* | 8186 ± 1201*† | 14792 ± 1817*† | 10092 ± 799*† | 9291 ± 1053*† |
| RPE | — | 8.1 ± 0.4 | 12.0 ± 0.3 | 14.3 ± 0.4 | 17.0 ± 0.3 | 19.2 ± 0.2 | — | — |
| Work load (watt) | — | 10 | 82 ± 5.0 | 126 ± 10.2 | 156 ± 14.3 | 190 ± 21.2 | — | — |
| Number of subjects | 15 | 15 | 12 | 8 | 7 | 5 | 5 | 5 |
SAP, systolic arterial pressure; DAP, diastolic arterial pressure; MAP, mean arterial pressure; HR, heart rate; MSNA, muscle sympathetic nerve activity; AU, arbitrary units; Rec1, 3–5 min after the end of the exhausting exercise; Rec2, 8–10 min after the end of the exhausting exercise. Total MSNA was taken as the product of mean burst strength and burst frequency. Statistical indicators depict responses between the indicated conditions for the five subjects who completed all stages.
P < 0.05 versus Rest;
P < 0.05 versus Moderate. Numerical data are group averages from all subjects (including the subjects who could not accomplish the entire exercise protocol) ± s.e.m.