Even moderate heat strains the human heart

2023-11-29山东齐现云

疯狂英语·新悦读 2023年10期

山东齐现云

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

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 (心血管压力), 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 (阈值) 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.”