After George had a heart attack at age 40, he decided to change his lifestyle. Which form of physical activity would best help him improve the health of his heart?
1. swim for 20 minutes Tuesday and Friday; lift weights for 20 minutes Monday, Wednesday, and Saturday
2. swim for 20 minutes Tuesday and Friday; run or walk briskly for 30 minutes Sunday, Wednesday, and Saturday
3. ride an exercise bike for 20 minutes Tuesday and Friday; walk leisurely for 20 minutes Sunday, Monday, Wednesday, and Saturday