Effect of exercise intensity on skeletal muscle AMPK signaling in humans

The effect of exercise intensity on skeletal muscle AMP-activated protein kinase (AMPK) signaling and substrate metabolism was examined in eight men cycling for 20 min at each of three sequential intensities: low (40 ± 2% V o 2 peak), medium (59 ± 1% V o 2 peak), and high (79 ± 1% V o 2 peak). Muscle free AMP/ATP ratio only increased at the two higher exercise intensities ( P