Table 2.
Cerebrovascular Hemodynamics at Rest and During Cognitive Challenge at Increasing Altitudes (Mean ± Standard Deviation)
| 1400 m |
3440 m (day 3) |
4240 m (day 7) |
p-value (partial-η2) |
||||||
|---|---|---|---|---|---|---|---|---|---|
| Rest | Stroop | Rest | Stroop | Rest | Stroop | Alt | Stroop | AxS | |
| Heart rate (minutes−1)^ | 71 ± 10 | 78 ± 14 | 75 ± 9 | 81 ± 12 | 77 ± 11 | 82 ± 10 | 0.36 (0.8) | 0.01 (0.3) | 0.51 (0.1) |
| SPO2 (%) | 94 ± 2 | 96 ± 1 | 88 ± 3‡ | 89 ± 3‡ | 85 ± 2‡,# | 86 ± 1‡,# | 0.01 (0.9) | 0.04 (0.5) | 0.71 (0.0) |
| SBP (mmHg) | 118 ± 8 | 119 ± 8 | 121 ± 7 | 123 ± 7 | 128 ± 10‡,# | 134 ± 10‡,# | 0.01 (0.8) | 0.16 (0.3) | 0.40 (0.1) |
| DBP (mmHg) | 67 ± 10 | 68 ± 10 | 71 ± 5‡ | 73 ± 12‡ | 79 ± 6‡,# | 80 ± 7‡,# | 0.01 (0.8) | 0.43 (0.1) | 0.99 (0.0) |
| PP (mmHg)^ | 51 ± 10 | 51 ± 8 | 50 ± 10 | 50 ± 10 | 49 ± 7 | 54 ± 8 | 0.52 (0.1) | 0.48 (0.1) | 0.36 (0.0) |
| MAP (mmHg) | 84 ± 8 | 85 ± 9 | 87 ± 4‡ | 89 ± 11‡ | 95 ± 7‡,# | 98 ± 7‡,# | 0.01 (0.8) | 0.26 (0.2) | 0.90 (0.0) |
| MCA conductance (cm/s/mmHg) | 0.77 ± 0.15 | 0.79 ± 0.17 | 0.75 ± 0.12 | 0.77 ± 0.12 | 0.69 ± 0.16‡ | 0.71 ± 0.13‡ | 0.03 (0.4) | 0.29 (0.2) | 0.99 (0.0) |
| ACA conductance (cm/s/mmHg) | 0.66 ± 0.12 | 0.69 ± 0.16 | 0.65 ± 0.18 | 0.66 ± 0.20 | 0.58 ± 0.18 | 0.58 ± 0.17 | 0.28 (0.2) | 0.38 (0.1) | 0.86 (0.0) |
Partial-η2 quantifies effect size and portion of variance accounted for by a specific main/interaction effect.
^
p-values represent transformed data to meet normality assumptions.
‡
Altitude effect, p < 0.05 versus 1400 m; #altitude effect, p < 0.05 versus 3440 m.
ACA, anterior cerebral artery; Alt, high-altitude hypoxia; AxS, high-altitude hypoxia-by-Stroop interaction; DBP, diastolic blood pressure; MAP, mean arterial pressure; MCA, middle cerebral artery; PP, pulse pressure; SBP, systolic blood pressure.