Page 29 - Exercise 2

Page 29 - Exercise 2

Body Clock

Why do you wake up in the morning and go to sleep at night? The answer is that we all have a body clock. Your brain produces hormones, like melatonin and adrenaline, which control the way your body works. The body clock controls the production of these hormones, so that your body produces more at some times of the day and less at other times. As a result, you wake up and feel sleepy at different times of the day.

When light hits your eyelids in the morning, your brain switches off the sleep hormone, melatonin, your temperature rises and you wake up. In the evening, when it’s dark, your brain starts to produce melatonin again, and your body gets ready to go to sleep.

If you don’t get enough sleep, you will feel tired the next day According to a recent survey most teenagers say that they don’t get enough sleep. They need about nine hours, but they normally only get about seven hours. However, teenagers say that they go to bed at about 10 or 10.30 in the evening and they get up at about 7.30. That’s nine hours, so why don’t they get enough sleep?

The problem is that the body clock doesn’t stay the same all through your life. When you’re a child, you wake up naturally at about seven o’clock, but when you become a teenager, your body clock changes.

The natural time for a teenager to wake up is nine o’clock in the

morning and the natural time to go to sleep is midnight. When you become an adult, the body clock will go back to the early time again.

Scientists don’t know why

Modern technology makes the problem worse. A lot of teenagers have TVs, computers, MP3 players and mobile phones in their bedrooms. The bright light from a TV or computer screen stops the production of melatonin and so keeps you awake. Loud music and texts from friends will also make it difficult to sleep.

Dermis, 14, is one of the teenagers in the survey. ‘I go to bed at 10.15 every night, but I don’t get nine hours sleep,’ says Dennis. ‘I know that I won’t go to sleep if I switch the light off straightaway So, I normally read and listen to music or the radio for an hour and a half. My parents don’t understand. When I’m awake in the evening, they say: “Go to bed.” Then at 7 30 in the morning when I’m asleep, they say: “Get up.” ‘

Another teenager in the survey Anita, says: ‘It’s bad for me in England. I start school at 8.45, but it’s worse for my friend, Suzie, in the USA She has to get up at 6, because she starts school at 7.15!’

Some scientists now think that the school day for teenagers should start later - at about 10 am.