英語聽力文摘 天冷不宜鍛煉？
天冷不宜鍛煉?
D: Woo……It's freezing out.
Y: Come on, It's not that cold.
D: Sure it is. Yael.I guess there's just no way I can go jogging today.
Y: Oh, so that's what this all about.
D: Not really. What if my lungs freeze?
Y: Actually, your body is designed so that by the time air reaches your lungs, it’s been warmed up and moisturized by your nasal passages, throat, and trachea. Besides, the blood supply in your lungs is so well developed that there’s virtually no way they can freeze–the circulating blood keeps them nice and toasty.
D: Oh,yeah. So why does it hurt to breathe this really cold?
Y:Well,when the air is frigid, it doesn’t warm up sufficiently before it reaches the airways leading to your lungs, and so it shocks the surrounding muscles and causes them to contract. This, in turn, causes your bronchial tubes to contract too, which results in that tight, prickly feeling.
D: Uh,sounds dangerous especially when you exercise in breathe to your mouth. What if my tongue freezes?
Y: Well,Don.Unless you suffer from asthma, breathing in cold air won’t hurt you–and you’d have to worry about frostbite to your fingers and toes long before worrying about your tongue freezing.
D：哇，外面太冷了。
Y：不會吧，沒那么夸張。
D：確實很冷啊。我想今天也沒辦法跑步了。
Y：原來你是不想鍛煉。
D：也不完全是。如果我的肺結(jié)冰了怎么辦?
Y：實際上，我們的身體是有應(yīng)對措施的。當(dāng)空氣進入肺部之前就已經(jīng)被鼻腔，喉嚨和氣管加濕，加熱。另外，肺部里的血液供給很充足，幾乎沒有可能結(jié)冰-——血液循環(huán)讓肺部保持正常和舒適。
D：是嗎?那為什么在呼吸冷空氣時會疼痛?
Y：因為在寒冷的空氣到達通向肺部的氣管時還沒有得到充分的熱身，所以沖擊到周圍的肌肉使其收縮。轉(zhuǎn)而使得支氣管收縮，因此你就會有緊繃刺痛的感覺。
D：聽起來很危險，特別是用嘴呼吸時，如果我的舌頭結(jié)冰的怎么辦?
Y：吸入的冷空氣不會對你造成傷害，除非你患有哮喘。你應(yīng)該擔(dān)心手指和腳趾的凍瘡而不是舌頭結(jié)冰。
