If you want to improve your cardiovascular fitness, start doing an aerobic exercise you enjoy such as walking, jogging, cycling, swimming, or aerobics. Try to do this activity at least 10 to 15 minutes, 3 times a week. Gradually work your way up to 30 minutes a day, 3 to 5 times a week by adding 1 or 2 minutes to your session every few weeks. Additionally, you can use a heart rate monitor or fitness app to track your progress and help you stay motivated. To learn how to use interval training to improve your cardiovascular fitness, read more from our Trainer co-author.