The most effective methods for improving cardiovascular fitness include engaging in aerobic exercise such as running, cycling, swimming, or brisk walking. Consistency is key, with recommendations suggesting at least 150 minutes of moderate or 75 minutes of vigorous activity per week. Incorporating interval training, where periods of high-intensity exercise are alternated with recovery periods, can further enhance cardiovascular adaptations. Strength training also contributes to cardiovascular health by improving overall muscle efficiency. Lastly, ensuring proper nutrition and hydration can support optimal performance and recovery.