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We compared in human skeletal muscle the effect of absolute vs. relative exercise intensity on AMP-activated protein kinase (AMPK) signaling and substrate metabolism under normoxic and hypoxic conditions. Eight untrained males cycled for 30 min under hypoxic conditions (11.5% O₂, 111 ± 12 W, 72 ± 3% hypoxia V̇o_{2 peak}; 72% Hypoxia) or under normoxic conditions (20.9% O₂) matched to the same absolute (111 ± 12 W, 51 ± 1% normoxia V̇o_{2 peak}; 51% Normoxia) or relative (to V̇o_{2 peak}) intensity (171 ± 18 W, 73 ± 1% normoxia V̇o_{2 peak}; 73% Normoxia). Increases (P < 0.05) in AMPK activity, AMPKα Thr¹⁷² phosphorylation, ACCβ Ser²²¹ phosphorylation, free AMP content, and glucose clearance were more influenced by the absolute than by the relative exercise intensity, being greatest in 73% Normoxia with no difference between 51% Normoxia and 72% Hypoxia. In contrast to this, increases in …