Aerobic means “with oxygen.” So when you run, bike, walk, swim, and do similar exercises, you take in more oxygen and move it to your muscles. This gets your blood pumping, makes your heart stronger, and lowers your blood pressure. Set a goal to exercise for 30 minutes, 5 to 7 days a week. Break it up into small chunks if needed. If you walk, know that moderate to intense speeds -- at least 3 miles an hour -- offer the best health benefits.