BBC Learning English Entertainment{How flying affects you}

Jackie: When you take off there’s a pressure change so get as your body works harder to get more oxygen, your breathing and pulse rate speed up. Another thing about our breathing when we’re flying is that the air in a plane is recycled – or reused – very often, which means you’re breathing in a lot of other people’s air. The ventilation – the movement[coolplayer width=”200″ height=”40″ charset=”GBK” autoplay=”false” loop=”true” download=”false”]http://www.storyday.com/download/audio/entertainment_070111_flying.mp3
of air – isn’t great and lots of people are together in a small space. This means you’re at a greater risk of catching illnesses. According to medical aviation expert Dr Mark Chanjo, some parts of the plane tend to get better ventilation than others. Where is ventilation usually a bit better?

Dr Mark Chanjo
The air is circulated about 12 to 15 times an hour. There is some variation, I mean, if
you’re sitting up in first class, you’re going to have better ventilation than if you’re
sitting in the back of the aircraft.
Jackie: Well, no surprises there. If you want better air, you’ll have to pay more
money and go in first class.

Jackie: Another flying-related problem which some people worry about is called deep vein thrombosis. This happens when the blood forms clot in the leg. A clot is when the blood in part of your body stops being as liquid as it should be and sort of clumps together. But as Michael Bagshaw tells us, it is a rare problem–studies show it doesn’t happen often. How often does it happen, according to Michael

Michael It would appear that the risk of thrombosis is about 1 per cent in people undergoing these really long flights of greater than ten hours or so.

Jackie: So only one in hundred people is at risk of getting thrombosis on a long flight. Michael says there’s also study which shows that those who did get the condition all had something in common about where they were sitting.What was it?

Michael All the deep vein thromboses that were detected occurred in people who were sitting in non-aisle seats, where, effectively, they were trapped and couldn’t easily get out to walk around the cabin.

Jackie: Michael said all those who got deep vein thrombosis were sitting in non-aisle sites. An’aisle seat’is next to the part of the plane where people walk up and down–’the aisle’ -so you’re usually more able to move your legs around if you sit there.Non-aisle seats are in between other seats or by the window and it’s not so easy to stretch your legs. Why is this important when it comes to deep vein thrombosis? Listen to find out.

Michael Normally of course the blood is fluid in the body and as we’re walking around, the blood that is in the legs is actually being massaged by the muscles in the legs back into the body.If you’re sitting in an aircraft, or indeed any other seat for a long period of time and not able to move about, that natural movement of the blood back towards the body simply doesn’t take place, the blood stagnates in the leg, if you like, and in some cases you’ll see the formation of clot.

Jackie: Michael says that if you’re sitting and not able to move around much, the blood doesn’t flow around your body properly.It stagnates–it stays where it is–and could form clot. A common problem with long flights occurs when you cross time zones.You might leave Japan in daylight, travel for 12 hours and when you arrive in England you’re body is telling you it’s bed time and it should be night–but the problem is daytime has onlyjust started in England.This is when you’re at risk of something we call jet lag. Natural light plays an important part in affecting the natural rhythm or cycle of our bodies, in particular, sleep. If we get lot more daylight than usual, it confuses our bodies.Listen to Michael.How long does it usually take us to get used to the change?

Michael Now the body’s rhythm will still follow its own cycle, but what’s now missing is the trigger which resets it is coming at the wrong time. So the sun is rising not when it should it train with the body, so the body has to be reset–its time clock has to be reset-and it takes a few days for this to happen.

Jackie: Did you get the answer? It usually takes few days for us to get over jet lag because our body clock has to reset–start again and get used to the new daylight hours. No wonder flying makes us so tired.Our bodies have to work hard to cope with so many changes. I think next time go on holiday, I’lljust take short train ride down to the seaside –much less stressful!


发表于 2007-01-16 16:14:22 目录:英语学习 [RSS 2.0] 您可以评论. Pinging 不可用.
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