Figure 6. Effects of skin hypoxia on systolic blood pressure (SBP) and heart rate (HR) (blue = normoxia, red  =  skin hypoxia; left = baseline, right  =  during rebreathing).

Note that there were statistically significant increases (P<0.0001) in systolic blood pressure with skin hypoxia (1) at baseline but this was converted to a statistically significant decrease (P<0.0001) during rebreathing (2), left panel. The changes were similar for heart rate during the two condition of the experiment, right panel (analysis of records from surface recording devices such as ear oximeter).