Section 4. Genetic and Molecular Aspects of Intermittent Hypoxia; The Role of HIF-1 and ROS in Cellular and Systemic Responses to Intermittent Hypoxia; Genetic Selection for Tolerance and Adaptation to Hypoxia; Mitochondrial Signaling in Formation of Body Resistance to Hypoxia; HIF1a, HIF2a, HIF3a and HIF1β mRNA Expression Changes in Different Tissues under Intermittent Hypoxic Training; Hypoxia and Stem Cells;