Once we’ve been sleeping for at least an hour, anabolic hormones start to flood our system. Testosterone and human growth hormone (HGH), both of which are integral to muscle and bone growth, are released after the first REM cycle and stay elevated until we wake. These hormones increase protein synthesis, or the generation of proteins specifically designed to facilitate physical repair.3 This means much of the protein athletes eat, diligently counted gram by gram throughout the day, goes to waste if they aren’t sleeping enough.
