★英語聽力頻道為大家整理的初中英語聽力下載mp3免費下載：嬰兒的心率，供大家參考。更多閱讀請查看本站英語聽力頻道。
Heart Rate: What A Baby’s Heart Rate Should Be
嬰兒的心率應該為多少呢？
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’?
想象這樣一個畫面，剛為人父母的他們正坐在沙發(fā)上溫聲細語的哄著孩子。孩子安靜了不吵了，所有人都處于靜息狀態(tài)。 所以這時他們的心率處于最低水平，對于成年人來說大約每分鐘60到70次。那么嬰兒的心率是多少呢？你認為嬰兒的心率與父母的心率比起來是高還是低？
Baby Bliss
嬰兒福氣
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’?
新生兒的靜息心率大約在100到150次每分鐘，比同等條件下的成年人要高。事實上，一個新生兒的靜息心率大致相當于一個成年人干重活時的心率。
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.
這種現(xiàn)象出于什么目的？為什么新生兒的心率要比成年人的要快？部分原因在于新生兒生長的非常快。他們身體上的每個細胞都要消耗能量來維持生長。
The process requires not only an abundance of milk but also oxygen, and it produces large amounts of carbon dioxide as waste.
在生長的過程中不僅需要牛奶還需要氧氣，而且會產(chǎn)生大量的代謝廢物二氧化碳。
Babies’ hearts work overtime to keep supplying oxygen and removing carbon dioxide to fuel their amazing growth.
為了提供足夠的氧氣并將二氧化碳運出體外，以達到快速生長的目的，嬰兒的心臟都是超負荷工作的。
The Animal World
動物世界。
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.
但是生長不是的原因，因為它不僅僅發(fā)生在我們正在談論的嬰兒身上。成年吉娃娃犬的心率要比成年大象快的多。為什么？吉娃娃犬有一個較大的表面體積比。換句話說，吉娃娃犬的皮膚面積比內部組織面積要大，這就意味與一個大型動物相比，它會向周圍散失更多的熱量。
Babies’ hearts beat much faster than their parents’, both to fuel their growth and make up for greater heat loss to the environment.
嬰兒的心率比他們父母的心率快，是由于生長和補充散失到環(huán)境中的大量能量的雙重原因造成的。
So little hearts maintain a higher metabolic rate, pound for pound, than big hearts.
在均等的條件下，小心臟要承受比大心臟更高的代謝速率。
Heart Rate: What A Baby’s Heart Rate Should Be
嬰兒的心率應該為多少呢？
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’?
想象這樣一個畫面，剛為人父母的他們正坐在沙發(fā)上溫聲細語的哄著孩子。孩子安靜了不吵了，所有人都處于靜息狀態(tài)。 所以這時他們的心率處于最低水平，對于成年人來說大約每分鐘60到70次。那么嬰兒的心率是多少呢？你認為嬰兒的心率與父母的心率比起來是高還是低？
Baby Bliss
嬰兒福氣
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’?
新生兒的靜息心率大約在100到150次每分鐘，比同等條件下的成年人要高。事實上，一個新生兒的靜息心率大致相當于一個成年人干重活時的心率。
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.
這種現(xiàn)象出于什么目的？為什么新生兒的心率要比成年人的要快？部分原因在于新生兒生長的非常快。他們身體上的每個細胞都要消耗能量來維持生長。
The process requires not only an abundance of milk but also oxygen, and it produces large amounts of carbon dioxide as waste.
在生長的過程中不僅需要牛奶還需要氧氣，而且會產(chǎn)生大量的代謝廢物二氧化碳。
Babies’ hearts work overtime to keep supplying oxygen and removing carbon dioxide to fuel their amazing growth.
為了提供足夠的氧氣并將二氧化碳運出體外，以達到快速生長的目的，嬰兒的心臟都是超負荷工作的。
The Animal World
動物世界。
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.
但是生長不是的原因，因為它不僅僅發(fā)生在我們正在談論的嬰兒身上。成年吉娃娃犬的心率要比成年大象快的多。為什么？吉娃娃犬有一個較大的表面體積比。換句話說，吉娃娃犬的皮膚面積比內部組織面積要大，這就意味與一個大型動物相比，它會向周圍散失更多的熱量。
Babies’ hearts beat much faster than their parents’, both to fuel their growth and make up for greater heat loss to the environment.
嬰兒的心率比他們父母的心率快，是由于生長和補充散失到環(huán)境中的大量能量的雙重原因造成的。
So little hearts maintain a higher metabolic rate, pound for pound, than big hearts.
在均等的條件下，小心臟要承受比大心臟更高的代謝速率。