What Your Muscles Are Actually Doing When You Rest
Muscle fibres do not grow during a workout. They tear. The microscopic damage caused by resistance training or high-intensity cardio triggers a repair process called muscle protein synthesis, and that process runs almost entirely during rest, particularly during deep sleep, when growth hormone secretion peaks. Skip the rest, and you interrupt the repair before it completes. The muscle stays damaged rather than adapting to become stronger.Cortisol, the body's primary stress hormone, rises sharply during intense exercise. Under normal conditions, it drops during recovery. When training sessions stack without adequate rest between them, cortisol stays elevated. Elevated cortisol suppresses testosterone production, accelerates muscle protein breakdown, and shifts the body into a catabolic state, the opposite of what any training programme is designed to achieve.
