We further underscore the physiological importance of the PHD2-HIF-axis by showing that HIF-1 promotes glycogen synthesis and initiates a metabolic shift to glycolytic energy production by increasing glucose uptake, glycolytic flux, pyruvate-to-lactate flux and lactate secretion in astrocytes and neurons (Figure 9) resulting in improved intrinsic tolerance to ischemia. Here, EGLN1 is linked to ischemia.