英语听力 学英语,练听力,上听力课堂! 注册 登录
> 在线听力 > 有声读物 > 英语杂志 > 英语听力文摘 >  第710篇

英语听力文摘697 婴儿的心率应该是多少呢?

所属教程:英语听力文摘

浏览:

2018年06月08日

手机版
扫描二维码方便学习和分享
https://online2.tingclass.net/lesson/shi0529/0007/7643/697.mp3
https://image.tingclass.net/statics/js/2012
Heart Rate: What A Baby’s Heart Rate Should Be

Picture new parents cooing at their baby on the couch. The baby’s quiet and calm, and everyone’s at rest. So their heart rates are low, maybe 60 or 70 beats a minute for the adults. What about the baby? How do you think the baby’s heart rate compares to the parents’?

Baby Bliss

Newborns have resting heart rates around 100 to 150 beats per minute, way higher than that of adults. In fact, a newborn’s resting heart rate is in the ballpark of the target heart rate for an adult doing a heavy workout. What gives? Why do newborns’ hearts beat so much faster than adults’?

Part of the answer lies in the fact that babies grow so dramatically. They burn food in every cell of their bodies to fuel that growth.

The process requires not only an abundance of milk but also oxygen, and it produces large amounts of carbon dioxide as waste.

Babies’ hearts work overtime to keep supplying oxygen and removing carbon dioxide to fuel their amazing growth.

The Animal World

But growth isn’t the only factor, because it’s not just baby animals we’re talking about. Adult Chihuahuas have much higher heart rates than adult elephants. Why? Chihuahuas have a greater surface to volume ratio. In other words, the Chihuahua has a greater proportion of skin than internal tissue, which means it loses more heat to the environment, relatively speaking, than a larger animal.

Babies’ hearts beat much faster than their parents’, both to fuel their growth and make up for greater heat loss to the environment.

So little hearts maintain a higher metabolic rate, pound for pound, than big hearts.

用户搜索

疯狂英语 英语语法 新概念英语 走遍美国 四级听力 英语音标 英语入门 发音 美语 四级 新东方 七年级 赖世雄 zero是什么意思临汾市新东城贤庭(华州路)英语学习交流群

网站推荐

英语翻译英语应急口语8000句听歌学英语英语学习方法

  • 频道推荐
  • |
  • 全站推荐
  • 推荐下载
  • 网站推荐