李菲

Most of us use alarm clocks to wake up at the right time for school or work. We look at our watches to know the right time for the bus or train. However， there is also a right time to eat， sleep， exercise， and take medicine， too. We cant look at a clock for the right time for these activities. We must listen to the clock inside our bodies： the biological clock.

Barbara Wells exercised every morning. She woke up at 6：00 am. She ran about two miles before she went to work. But Barbaras legs and back started to hurt. She did some exercises before she ran. But her legs and back still hurt. She ran slower， but the pain didnt stop. Barbara talked to her doctor. The doctor said， “Dont run in the morning. Try to exercise later in the day. That is the time when your body is at the right temperature for exercise. Your heart and lungs are very strong in the afternoon， too.” Now Barbara exercises after work. Her legs and back dont hurt anymore.

Today， doctors are learning more about chronobiology， the study of biological clocks. They are learning about the importance of time for our bodies. For example， it is best for people to go to sleep at the same time every night and to eat only when theyre hungry. Also， doctors discovered that some illness， such as heart attacks， occur most often in the morning. This information tells them that the best time to take heart medication may be at night. When patients take heart medicine at night， they may prevent a heart attack in the morning.

Many doctors believe chronobiology can help us live healthier lives. It may be the right time to listen to these doctors！

吉林長(zhǎng)春? ?李? ?菲? ?供稿