After activity 1. Muscle cools down and permits enzymes to work at optimal temperature 2. Restoration of muscle glycogen. Liver glycogen is broken down to yield glucose. Liver glucose is released into the blood.
Blood glucose is taken up by muscle.
Muscle glucose is polymerized to form glycogen. Muscle creatine phosphate levels are restored. Gluconeogenesis occurs in the liver using lactate as starting material. Restoring muscle to normal condition takes time during which there is an increased oxygen demand. This is perceived as oxygen debt.