Effect of exercise intensity and hypoxia on skeletal muscle AMPK signaling and substrate metabolism in humans

Abstract

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 V̊O2 peak; 72% Hypoxia) or under normoxic conditions (20.9% O2) matched to the same absolute (111 ± 12 W, 51 ± 1% normoxia V̊O2 peak; 51% Normoxia) or relative (to V̊O2 peak) intensity (171 ± 18 W, 73 ± 1% normoxia V̊O2 peak; 73% Normoxia). Increases (P < 0.05) in AMPK activity, AMPKα Thr172 phosphorylation, ACCβ Ser221 phosphorylation, free AMP content, and glucose clearance were more in..