Table 2.
Peak exercise data
| Older (n = 22) |
Younger (n = 22) |
||||
|---|---|---|---|---|---|
| Men (n = 10) | Women (n = 12) | Men (n = 11) | Women (n = 11) | P Value | |
| V̇o2, l/min | 2.63 ± 0.20 | 1.89 ± 0.12 | 3.91 ± 0.29 | 3.01 ± 0.15 | *†P < 0.05 |
| V̇o2, ml·kg−1·min−1 | 34.7 ± 2.0 | 30.6 ± 2.6 | 53.4 ± 3.1 | 51.7 ± 2.8 | *†P < 0.05 |
| V̇o2, %predicted | 119 ± 5 | 122 ± 6 | 123 ± 6 | 140 ± 7 | |
| V̇co2, l/min | 2.92 ± 0.20 | 2.23 ± 0.14 | 4.33 ± 0.27 | 3.34 ± 0.17 | *†P < 0.05 |
| RER | 1.12 ± 0.20 | 1.18 ± 0.02 | 1.12 ± 0.03 | 1.11 ± 0.02 | |
| HR, beats/min | 150 ± 5 | 153 ± 5 | 186 ± 3 | 185 ± 3 | *P < 0.05 |
| HR, %predicted | 100 ± 2.9 | 98 ± 3.2 | 96 ± 1.6 | 95 ± 1.8 | |
| SpO2, % | 98 ± 1 | 98 ± 1 | 97 ± 1 | 98 ± 1 | |
| VT, liters | 2.84 ± 0.18 | 1.95 ± 0.14 | 2.96 ± 0.17 | 2.19 ± 0.08 | †P < 0.05 |
| Fb, breaths/min | 39.5 ± 4.1 | 45.7 ± 3.2 | 51.5 ± 2.5 | 55.1 ± 3.0 | *P < 0.05 |
| V̇e, l/min | 108 ± 8 | 85 ± 4 | 151 ± 10 | 119 ± 5 | *†P < 0.05 |
| V̇e/V̇o2 | 42.4 ± 3.4 | 46.3 ± 2.8 | 39.7 ± 2.2 | 39.8 ± 1.2 | *P < 0.05 |
| V̇e/V̇co2 | 37.6 ± 2.4 | 39.1 ± 2.1 | 35.4 ± 1.7 | 35.9 ± 1.1 | *†P < 0.05 |
| , mmHg | 30.8 ± 0.9 | 32.2 ± 1.4 | 33.3 ± 3.8 | 31.6 ± 1.4 | |
| Work rate, W | 172 ± 10 | 140 ± 11 | 269 ± 21 | 222 ± 12 | *†P < 0.05 |
| V̇o2:work rate slope | 11.7 ± 0.7 | 10.8 ± 0.50 | 11.5 ± 0.3 | 11.2 ± 0.3 | |
| EELV, %TLC | 56 ± 3 | 56 ± 2 | 50 ± 2 | 51 ± 2 | *P < 0.05 |
| EILV, %TLC | 91 ± 1 | 92 ± 1 | 91 ± 2 | 91 ± 1 | |
| Wb, J/min | 257 ± 24 | 236 ± 28 | 335 ± 52 | 307 ± 39 | *†P < 0.05 |
| Resistive Wb, J/min | 76 ± 19 | 101 ± 20 | 61 ± 16 | 140 ± 33 | †P < 0.05 |
| Viscoelastic Wb, J/min | 181 ± 32 | 135 ± 23 | 274 ± 42 | 166 ± 22 | *P < 0.05 |
| V̇eCAP, l/min | 151.1 ± 13.2 | 118.4 ± 8.2 | 220.4 ± 9.1 | 181.1 ± 11.8 | *†P < 0.05 |
| V̇e/V̇eCAP, % | 73.2 ± 4.3 | 75.1 ± 4.9 | 69.6 ± 4.4 | 67.5 ± 3.7 | *P < 0.05 |
| Dyspnea, Borg scale | 4.6 ± 0.7 | 5.3 ± 0.6 | 6.0 ± 0.8 | 6.5 ± 0.9 | *P < 0.05 |
| Leg discomfort, Borg scale | 6.2 ± 0.9 | 6.3 ± 0.8 | 9.2 ± 0.8 | 8.8 ± 0.5 | *P < 0.05 |
All data are presented as means ± SE. V̇o2, oxygen uptake; V̇co2; carbon dioxide output; RER; respiratory exchange ratio; HR, heart rate; SpO2, oxygen saturation by pulse oximetry; VT, tidal volume; Fb, breathing frequency; V̇e, minute ventilation; V̇e/V̇o2, ventilatory equivalent for oxygen; V̇e/V̇co2, ventilatory equivalent for carbon dioxide; , end-tidal carbon dioxide; EELV, end-expiratory lung volume; EILV, end-inspiratory lung volume; Wb, work of breathing; V̇eCAP, ventilatory capacity.
*
Older vs. younger subjects.
†
Men vs. women.