环球英语 — 207：Body Clock
Voice 1
Thank you for joining us for today’s Spotlight. I’m Rebekah Schipper.
Voice 2
And I’m Joshua Leo.
Voice 1
Do you ever think about time? What is it? You cannot touch it, smell it or taste it. But you cannot escape it. Time is all around us. We organize our day by what time it is. We wake from sleep in the morning at a particular time. We go to bed at another time. We work, we eat, we play; all because of time. But why? What if there was no time? Could we exist without time?
Voice 2
Today’s Spotlight is on our body’s natural clock. Many people believe that our bodies keep their own time. So, do we really need clocks? Do we really need time?
Voice 1
Do you ever feel like your body wakes from sleep at a particular time each morning? Do you feel hungry for food at about the same time each day? Are you usually ready to go to bed at the same time each night? Have you experienced a repeating pattern with your body?
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Research shows that people’s bodies have their own rhythms. These rhythms help people know when to get up in the morning. They help people to know when to eat. These rhythms help people know when to go to bed. Scientists believe that body rhythms repeat every twenty–four hours and eleven minutes, almost the same length as a day!
Voice 1
So, how does the body’s clock work? Well, in your brain there is a small organ called the suprachiasmatic nucleus, or the SCN. The SCN controls the body’s clock. It commands other organs and systems in the body. It causes everything to work together to tell your body what time it is. For example, in the morning your blood pressure rises. This helps you to be able to physically get out of bed.
Voice 2
And, in the afternoon and evening your liver produces special enzymes, or chemicals. These enzymes make you feel hungry for food at a particular time.
Voice 1
Then, at night, a gland in the bottom part of your brain starts to work. The SCN causes the gland to produce another kind of chemical called melatonin. Melatonin makes you feel tired. As you sleep, the temperature in your body drops. In the morning the sun comes up. The light hits your eyes. This stops your body from producing melatonin. Soon you feel ready to get out of bed! The SCN organ makes sure that this pattern repeats day after day.
Voice 2
In 1962, a scientist named Michel Siffre discovered the body’s natural clock. Michel wanted to study the movement of an ice glacier. He went into an underground cave to find the glacier. But while he was in the cave he had an idea. Michel said,
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“I had the idea of my life. I decided not to take a (clock) in the cave. I decided to live without time (signals).”
Voice 2
In the cave Michel was away from day light, clocks, and routines, or day time patterns. He hoped to discover if the body had its own rhythm. Michel said,
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“I decided to live following my feelings of hunger, my feelings of going to sleep. In the cave it is always dark. (So) your body has to follow its own sense.”
Voice 1
Each day Michel would call his team members. They were working above ground. Michel would call them every time he woke from sleep. He would call them every time he ate, exercised, and even when he expelled waste from his body. Michel would then tell his team what time he thought it was. But, he really had no idea! His team wrote down the time of each of Michel’s body behaviours. Then they compared Michel’s estimated time with the real time. They did this for two months.
Voice 2
So, was Michel able to know what time it was just by following his body’s natural ways? Well, the results showed that Michel followed a clear repeating pattern each day. The scientists measured Michel’s days from the time he woke from sleep in the morning to the time he woke from sleep the next morning. They found the average length of Michel’s days in the cave. They were just over twenty–four hours! That was very close to the Earth’s natural day length! So, it seems that our bodies have a natural twenty–four hour rhythm.
Voice 1
Many people have body clocks that run close to a twenty–four hour day. But not everybody’s body clocks are the same. Some people have extremely different body clocks! For example, members of the McQuerry family in the United States have very different daily patterns. Mr. McQuerry and his daughter rise from sleep every day at four in the morning. They cannot stop this from happening. Their bodies naturally wake up! The daughter works on her school work. The father goes to the store to buy the family’s food. These two McQuerry’s are extremely tired very early in the night. They feel like they must sleep.
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But Mrs. McQuerry and her son have different body clocks. They sleep until late in the morning. They stay up late at night. The McQuerry family sometimes wishes that their body clocks were the same. They wish they could have more time to spend together.
Voice 1
The McQuerry family’s situation is rare. The father and daughter suffer from Advanced Sleep Phase Syndrome, or ASPS. It is a disease of the body’s natural clock. Mr. McQuerry and his daughter’s body clocks are pushed forward. That makes them feel tired much earlier than most people. And it makes them rise very early in the morning. But the McQuerrys have learned about ASPS. They try to work around their different body clocks. They try to spend more time together.
Voice 2
The body’s natural clock is important, no matter what time you like to do things. The body clock is important for health. Several studies suggest that obeying your body’s clock can help reduce tiredness. And people who get at least seven hours of sleep are much less likely to be obese, or over a normal weight. Going to bed and getting up at the same time every day also keeps your body’s clock on schedule. Your body’s clock controls your body’s temperature, hormones, blood pressure and other important body systems. Changing your body’s pattern can cause serious health problems. So, be sure to listen to your body. Keeping to your body’s clock can keep you healthy!
Voice 1
Thank God for our body’s natural clock. It is just another small way that God cares for his most wonderful creation – us!
