中等温度也会让人类心脏有压力

齐现云

一项研究表明，在潮湿的环境下，空气温度达34℃会导致心率稳步上升。这种上升，也被称为心血管压力。

主题语境：人物与环境篇幅：346词建议用时：7分钟

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

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

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

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

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

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

ReadingCheck

1. 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.

2. 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.

3. 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.

4. When should you realize possible dangers of your heart accordingto 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.

LanguageStudy

Ⅰ. 日積月累

damp adj. 潮湿的

relevant adj. 相关的

potentially adv. 潜在地；可能地

identify v. 识别；认出

strategy n. 策略

indicate v. 表明

progressively adv. 持续稳定地

a series of 一系列

be exposed to 暴露于

at risk 处于危险中

Ⅱ. 单句填空

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.