Passage 2

“Sleep is a behavior and, like all behaviors, it differs greatly among people,” explains Dr. Carol Landis. “The greatest differences occur in the timing of sleep and the amount of sleep-the factors which are most important in determining whether you will wake up feeling rested.”

Research has found that people sleep better at different times during their daily cycle. For example, some people function better if they go to sleep early and rise early, while others feel more rested if they stay up late and sleep in. “Many people don’t pay attention to the timing of their sleep,” Landis notes. “Yet delaying or altering the time you go to sleep can have a major impact on how you feel when you wake up.”

The amount of sleep the average adult needs each night also differs. Some

people may be fine with six hours of sleep, while others need up to nine hours per night. Landis points out that those who follow a regular sleep schedule tend to function better on fewer hours, but she adds that most adults need at least six hours of sleep each night.

“A person’s sleeping patterns aren’t set in concrete,” Landis stresses.

Gradually altering the timing of sleep can help change sleep patterns. An“evening person” who needs to get to work early in the morning can try upping the time they go to bed by 30 minutes every few days. Within a few weeks, this slow adjustment will help“reset”the body clock.

In addition to maintaining a regular daily sleep schedule, Landis offers the

following tips on having a good sleep:

• Avoid cigarettes, caffeinated (含咖啡因的) drinks and food such as chocolate in the late afternoon and evening.
• Avoid alcohol in the evening. This can cause a person to wake up a few hours into sleep and interrupt sleep patterns.
• Finish exercising at least two hours before going to sleep. Exercise increases body temperatures and makes it more difficult to easily fall asleep.
•  Don’t sleep in a warm environment. A drop in a person’s body temperature is important at the beginning of deep sleep. People who sleep in a well-heated room or use an electric blanket may not sleep as soundly.
•  Catch up on missed sleep when you have the opportunity. To reduce your sleep debt, try taking a 30-minute nap (小睡) during the day before 4 p.m. or sleeping in on weekends when you have a chance.

 Which of the following is true according to Dr. Landis?