Table 2.
Mean values of oxygen consumption, mechanical efficiency, energy consumption, and respiratory exchange ratio during a graded exercise test before and after HIIT
| Preintervention (baseline) | Postintervention | |||||
|---|---|---|---|---|---|---|
| Young adults (n = 17) W = 12, M = 5 | Older adults (n = 13) W = 8, M = 5 | Young adults (n = 17) W = 12, M = 5 | Older adults (n = 13) W = 8, M = 5 | Group*Time effects | ||
| Rest | ||||||
| VO2 (ml.min −1 ) | 616 (2) | 730 (5)a | 580 (8)b | 610 (6)a , b | 11.8 | <0.01 |
| RER | 0.77 (0.01) | 0.76 (0.02) | 0.78 (0.02) | 0.71 (0.01) | 1.6 | 0.33 |
| EE (W) | 203 (13) | 240 (25)a | 190 (12)b | 210 (17)a , b | 21.8 | <0.01 |
| Intensity corresponding to ventilator threshold 1 (VT1) | ||||||
| HR (beats.min −1 ) | 110 (4) | 105 (3.5) | 100 (3) | 105 (3) | 1.1 | 0.23 |
| VO2 (ml.min −1 ) | 1149 (63) | 1168 (70) | 1045 (63)b | 1140 (60)b | 21.2 | <0.01 |
| RER | 0.84 (0.02) | 0.85 (0.02) | 0.81 (0.01) | 0.81 (0.01) | 1.6 | 0.33 |
| EE (W) | 183 (30) | 170 (30) | 169 (30)b | 160 (10)b | 11.8 | <0.01 |
| ME (%) | 22.5 (2.1) | 22.1 (0.8) | 25.8 (2.1)b | 26.1 (1.8)b | 24.6 | <0.01 |
| Intensity corresponding to ventilator threshold 2 (VT2) | ||||||
| HR (beats.min −1 ) | 151 (4) | 135 (6) | 145 (4) | 124 (5) | 1.1 | 0.23 |
| VO2 (ml.min −1 ) | 1540 (91) | 1717 (114)a | 1634 (95) | 1690 (136) | 11.2 | <0.01 |
| RER | 0.9 (0.01) | 0.9 (0.02) | 0.9 (0.01) | 0.9 (0.02) | 1.1 | 0.22 |
| EE (W) | 333 (30) | 360 (23)a | 320 (23)b | 316 (28)b | 21.5 | <0.01 |
| ME (%) | 24.1 (1.1) | 20.0 (1.3) a | 25.9 (1.2)b | 25.1 (1.3)b | 22.6 | <0.01 |
| Workload at VO2max | ||||||
| VO2 (ml.min −1 ) | 2221 (485) | 2338 (511) | 2278 (580) | 2298 (380) | 3.1 | 0.63 |
| RER | 1.1 (0.1) | 1.1 (0.1) | 1.1 (0.1) | 1.1 (0.01) | 1.2 | 0.11 |
| EE (W) | 706 (45) | 705 (50) | 600 (45)b | 610 (50)b | 11.1 | <0.01 |
| ME (%) | 25.5 (0.9) | 23.2 (2.2)a | 27.6 (0.8)b | 27.1 (1)b | 23.3 | <0.01 |
Values are mean ± SE (standard error). HR, heart rate; RER, respiratory exchange ratio; VO 2, oxygen consumption; EE , energy expenditure; ME, mechanical efficiency.
a
Significant difference between groups (P < 0.01).
b
Significant difference from baseline values (P < 0.01).