Even moderate heat strains the human heart

山東 齊現(xiàn)云

一項研究表明，在潮濕的環(huán)境下，空氣溫度達34℃會導(dǎo)致心率穩(wěn)步上升。這種上升，也被稱為心血管壓力。

主題語境：人物與環(huán)境 篇幅：346詞 建議用時：7分鐘

1Air temperatures as low as 34 ℃ can lead to a steady increase in heart rate under damp conditions, a study says.This rise, also known as cardiovascular strain (心血管 壓力), occurs even before a person's inner temperature starts to increase.

2The findings are among a series of recent results about the heart's struggles when exposed to heat.Scientists say this work is becoming more relevant as extreme heat events become more frequent.Just this week, the average temperature worldwide hit a record high two days in a row.

3“More people are going to be exposed to heatwaves and potentially be at risk,” says Rachel Cottle, a researcher in exercise physiology at the Pennsylvania State University in State College.But work to identify the combination of temperature and humidity that endangers the heart could inform strategies to protect human health, she says.

4To find the threshold (閾值) for heart risk exactly, Cottle and her colleagues got 51 young, healthy participants to engage in light physical activity inside a room, where the temperature or humidity rose every 5 minutes.The researchers monitored each individual's core temperature—the temperature of their inner organs—using sensors inside capsules that the participants had swallowed.The team also measured participants' heart rates.

5As the room got hotter, participants' heart rates increased and then steadied.But, as the room continued to heat up, the volunteers' heart rates started to rise again, and were still rising when the experiment ended—indicating cardiovascular strain.In humid conditions, participants who were walking slowly experienced cardiovascular strain when the temperature was around 34 ℃.When the air was dry, that threshold was around 41 ℃.Cardiovascular strain always began about 20 minutes before the participants' core temperatures started to rise.

6Because heart rate is so easy to measure, it could be a useful warning sign.“If all of a sudden you notice your heart rate going up quickly and progressively, then that might mean that your core temperature will start to rise,” Cottle says.“That's when you need to take preventive measures.”

Reading Check

Detail1.What can we learn from the study?

A.Air temperature is higher than before.

B.Air temperature influences heart health.

C.Human heart rates rise in wet conditions.

D.Heat events are endangering more seniors.

Detail2.Why is the outcome of the study crucial?

A.Heatwaves are more common.

B.Man is at the risk of extinction.

C.Global warming broke a record.

D.Humans care for their hearts more.

Gist3.What does paragraph 4 focus on?

A.Humans' core temperature.

B.Humans' heart risks.

C.How the experiment was conducted.

D.Why young people have better hearts.

Detail 4.When should you realize possible dangers of your heart according to Cottle?

A.When your heart rates stay unchanged.

B.When you're given warnings by doctors.

C.When your heart beats become slower than before.

D.When your heart beats increase faster.

Language Study

Ⅰ.日積月累

dampadj.潮濕的

relevantadj.相關(guān)的

potentiallyadv.潛在地；可能地

identifyv.識別；認(rèn)出

strategyn.策略

indicatev.表明

progressivelyadv.持續(xù)穩(wěn)定地

a series of 一系列

be exposed to 暴露于

at risk 處于危險中

Ⅱ.單句填空

1.________ (know) as “heart killer”, the nature disaster desires for urgent solution.

2.When ________ (expose) to extreme heatwaves for long, humans will fail to survive.

3.More and more people are ________ (potential) influenced by heatwaves.

4.Rising air temperatures are leading ________ more human heart problems.

5.Residents should be well informed ________ the changing air temperatures.

6.________ air temperatures get higher, our heart rates will increase and then steady.