Effect of 2-h hypoxic exposure on resting hepcidin levels in young adults

We evaluated the effects of acute hypoxic exposure on serum hepcidin levels. In a crossover design, 11 healthy individuals (9 men and 2 women) completed a 2-h period of seated rest in a hypoxic (HYP; fraction of inspired oxygen [FiO₂]: 12.5%) or normoxic control (CON; FiO₂: 20.9%) environment in the morning. Following the environmental exposure, participants rested in a CON environment for 6 h. Venous blood samples were collected at baseline, immediately post-exposure, and at 2-, 4-, and 6-h post-exposure. Serum erythropoietin (EPO) levels increased significantly over time in both conditions (p < 0.05). At 2-h post-exposure, the EPO response was significantly greater in HYP than in CON (p < 0.05). Serum erythroferrone (ERFE) levels did not differ significantly between the HYP and CON trials at any time point. Serum hepcidin levels increased significantly at 4- and 6-h post-exposure in both trials compared to baseline (p < 0.05). However, no significant differences in serum hepcidin levels were observed between the HYP and CON trials at any time point. These findings suggest that a 2-h hypoxic exposure enhances the erythropoietic response in young adults but does not suppress diurnal serum hepcidin or elevate ERFE levels.