Arterial oxygen tension during stay at high altitude
| Period at altitude h | Placebo kPa | Acetazolamide kPa | Theophylline kPa |
| 6 | 6.3±1.0 | 8.0±1.1* | 6.8±0.6 |
| 18 | 7.2±0.5 | 8.0±0.5** | 7.3±0.3 |
| 24 | 7.0±0.6 | 8.3±0.6** | 6.9±0.4 |
| 30 | 7.0±0.7 | 8.1±1.6* | 7.0±0.5 |
| 42 | 7.5±1.3 | 7.9±0.4# | 7.1±0.6 |
Data are presented as mean±sd
*: p<0.05 versus corresponding values in the placebo group and the theophylline group
**: p<0.01 versus corresponding values in the placebo group and the theophylline group
#: p=0.042 versus corresponding value in the theophylline group