Movement · foundations
Fitness is built during recovery, not during the workout. Sleep is the most powerful recovery tool you have.
Adaptation — stronger muscle, denser bone, a more efficient heart — happens between sessions, fueled by protein, sleep, and time. Train the same tissue again before it has recovered and you dig a hole instead of building.
Most adults need 7–9 hours. Deep sleep drives growth-hormone release and tissue repair; too little blunts recovery, raises resting heart rate, impairs glucose control, and increases injury and illness risk. Protecting sleep protects everything else.
Persistently elevated resting heart rate, poor sleep, low mood, nagging soreness, and stalled progress are the body asking for rest. An easy week often unlocks the next jump.