根据短文内容的理解，选择正确答案。

B

    Running is becoming popular these days. Many of us run for our health. Doctors say many of the health problems come from these bad habits: eating too much, drinking too much, smoking, and not taking enough exercise. Doctors tell us, "Eat and drink less, don't smoke, and exercise more."

    Running is a good form of exercise because it helps build a strong heart. It also helps most people loseweight. One 68­year­old woman runs three times a week. She runs to lose weight.

    Running is good for health in other ways, too. Many runners say running keeps colds and other small health problems away." Running is my doctor, "says one man.

    Running can also help people to relax. So today men and women of all ages enjoy running.