A healthy individual going to high altitude (i.e., 12,000 ft) at once fells breathless (extreme on exertion), has palpitation (consciousness of vigorous cardiac contraction), headache, fatigue, dizziness, weakness, nausea or vomiting, impairment of judgment and other mental processes, dimness of vision and often insomnia. This is called “acute mountain sickness”. After a few days at the same altitude their symptoms diminish and some even disappear. Concerning the immediate adjustment to hypoxemia, indicate with arrows the direction of change for the following variables: