The body's circadian rhythm influences exercise timing by regulating sleep-wake cycles and hormone release. This natural internal clock impacts energy levels, muscle strength, and endurance throughout the day. Typically, exercising during the afternoon or early evening can enhance performance due to peak levels of hormones like testosterone and optimal body temperature. Morning workouts may work better for some due to increased willpower and adherence. Understanding personal circadian patterns allows individuals to choose the best times for exercising, maximizing their fitness results and overall experience.