Improving cardiovascular fitness without running involves incorporating alternative forms of aerobic exercise that elevate your heart rate and challenge your cardiovascular system. Consider activities like cycling, swimming, rowing, or using cardio machines like the elliptical or stair climber, which provide low-impact options for improving cardiovascular health. High-intensity interval training (HIIT) workouts are another effective way to boost cardiovascular fitness, involving short bursts of intense exercise followed by brief periods of rest or lower-intensity recovery. Circuit training, dance workouts, and group fitness classes can also provide fun and challenging options for improving cardiovascular endurance without running. Be creative and experiment with different activities to find what you enjoy and what works best for your body and fitness goals.