The purpose of this study is:
- To study the effect of whole-body vibration on partial pressure of oxygen in arterial blood (PaO2), under hypobaric hypoxic conditions.
- To study the effects of whole-body vibration and hypobaric hypoxia on visual contrast sensitivity.
- To se if there is an increase in cytokines and other biomarkers under different hypobaric hypoxic conditions Our main hypothesis is that whole-body vibration may cause PaO2 to drop to a lower level, at a given altitude; than would be the case if there were no vibration present.