Table 1.
Cardiorespiratory and hemodynamic variables under normoxia, placebo and beetroot trials at rest and during submaximal and maximal exercise
| Normoxia | Placebo | Beetroot | P value | ||
|---|---|---|---|---|---|
| Norm vs. PL | PL vs. BR | ||||
| Rest | |||||
| VO2, mL/min | 297 ± 33 | 305 ± 47 | 296 ± 40 | 0.622 | 0.431 |
| VCO2, mL/min | 257 ± 30 | 277 ± 42 | 273 ± 38 | 0.257 | 0.788 |
| RER | 0.87 ± 0.07 | 0.92 ± 0.04 | 0.92 ± 0.06 | 0.207 | 0.807 |
| V E, L/min | 10.0 ± 1.4 | 10.8 ± 1.4 | 10.9 ± 1.7 | 0.183 | 0.919 |
| HR, bpm | 60 ± 7 | 64 ± 7 | 65 ± 5 | 0.058 | 0.757 |
| MAP, mmHg | 85 ± 5 | 88 ± 6b | 86 ± 7 | <0.001 | 0.085 |
| LA, mmol/L | 1.4 ± 0.3 | 1.6 ± 0.2 | 1.7 ± 0.2 | 0.206 | 0.122 |
| SpO2, % | 98.3 ± 0.8 | 88.1 ± 2.0b | 87.6 ± 1.5 | <0.001 | 0.590 |
| Submaximal exercise | |||||
| VO2, mL/min | 1908 ± 305 | 1442 ± 183b | 1382 ± 225 | <0.001 | 0.209 |
| VCO2 mL/min | 1744 ± 286 | 1384 ± 161b | 1277 ± 207a | <0.001 | 0.012 |
| RER | 0.91 ± 0.02 | 0.97 ± 0.07 | 0.93 ± 0.07 | 0.063 | 0.069 |
| VE, L/min | 48.5 ± 8.9 | 46.3 ± 5.7 | 44.4 ± 10.0 | 0.371 | 0.344 |
| HR, bpm | 140 ± 2 | 140 ± 4 | 141 ± 4 | 0.715 | 0.560 |
| MAP, mmHg | 100 ± 10 | 93 ± 5 | 92 ± 8 | 0.080 | 0.843 |
| SkBF, % | 544 ± 223 | 538 ± 222 | 560 ± 321 | 0.953 | 0.744 |
| LA, mmol/L | 2.8 ± 1.1 | 4.0 ± 2.1b | 3.8 ± 1.6 | 0.040 | 0.759 |
| SpO2, % | 96.6 ± 1.3 | 74.6 ± 5.2b | 73.8 ± 5.1 | < 0.001 | 0.592 |
| Maximal exercise | |||||
| VO2 peak, mL/min | 3127 ± 361 | 2450 ± 277b | 2612 ± 337 | <0.001 | 0.066 |
| VCO2 peak, mL/min | 3688 ± 457 | 3152 ± 416b | 3222 ± 301 | 0.003 | 0.516 |
| RER peak | 1.18 ± 0.06 | 1.29 ± 0.17 | 1.23 ± 0.09 | 0.105 | 0.254 |
| V E peak, L/min | 111.3 ± 20.1 | 117.5 ± 17.0 | 118.0 ± 16.6 | 0.210 | 0.914 |
| HR peak, bpm | 180 ± 9 | 178 ± 6 | 182 ± 5a | 0.352 | 0.031 |
| MAP, mmHg | 149 ± 14 | 133 ± 20 | 130 ± 16 | 0.071 | 0.441 |
| SkBF, % | 529 ± 287 | 535 ± 287 | 568 ± 222 | 0.950 | 0.832 |
| LA peak, mmol/L | 12.1 ± 1.7 | 10.3 ± 2.6 | 12.3 ± 2.8 | 0.064 | 0.078 |
| SpO2 nadir,% | 95.3 ± 1.5 | 69.4 ± 5.9b | 68.9 ± 6.1 | <0.001 | 0.683 |
Values are the means ± standard deviation (SD).
Norm, normoxia; PL, placebo; BR, beetroot; VO2, oxygen uptake; VCO2, carbon dioxide output; RER, respiratory gas exchange ratio; V E, ventilation; HR, heart rate; MAP, mean arterial pressure; LA, blood lactate concentrations; SpO2, arterial O2 saturation SkBF, skin blood flow in active muscle. Note that MAP was measured by the oscillometric method at rest.
a
P < 0.05 between placebo and beetroot.
b
P < 0.05 between normoxia and placebo.