Fig. 2. (A) Symptom scores for acute mountain sickness (AMS) severity and (B) arterial oxygen saturation measured by pulse oximetry (Sa_O2; %) during exercise in hypoxia. The different symbols in A represent the individual subjects in the two different trials. The solid squares in A represent the mean values ± S.E.M. for each trial. A drop in percentage Sa_O2 while exercising (*P<0.05 compared with the sedentary value) and a slight fluid retention (not shown) distinguished exercise (resulting in AMS) from rest (no AMS). Values are means + S.E.M. Adapted from Roach et al. (Roach et al., 2000).