文章大意:本文是一篇说明文。讲述了老年人在高温下更容易患上与热相关的疾病,原因是他们体液不足时会更多地出汗,强调了老年人对脱水的反应较弱,并提到了老年人更容易患有影响身体对温度反应的慢性疾病,给出了一些建议来提醒老年人在高温天气中锻炼活动时要补充水分。
Too much heat is not safe for anyone, yet seniors are at higher risk for heat-related illnesses than younger folks. A new Canadian study has highlighted a fascinating reason why: they sweat more when they’re running low on body fluids (液体).
When it’s hot out and you’re being active, you start perspiring, which helps your body regulate its temperature downward. It also makes you lose fluid, which in turn increases the concentration of sodium in your blood. When this concentration gets high(in other words, the body gets dehydrated (脱水), a younger adult will stop sweating as much, begin to feel overheated and thirsty, and likely reach for a glass of water. But older adults’ bodies tend to be less responsive to dehydration. Therefore, this can be challenging for older adults who typically do not adjust as well as others to sudden temperature changes. Additionally, older adults are more likely to have chronic (慢性的) medical conditions that affect the body’s response to temperature, and to take prescription medicines that alter the body’s ability to control temperature or sweat. A lot of sweating and fluid loss may continue without the warning of feeling uncomfortably thirsty. This ability to keep pushing may sound like a superpower, but it’s actually a reason to be extra careful: it brings a higher risk of heat exhaustion, heat stroke, and heat stress-related cardiovascular problems.
As a result, older people may need reminders to drink water while being active during a heat wave. It could be a good idea, for example, to set a recurring alarm on your watch or smart phone before heading out.
Also, since you can’t necessarily rely on your thirst, watch for other signs of dehydration, including infrequent urination (排尿), dark-colored urine, exhaustion, confusion, and dizziness.
8. According to the study, why are seniors at higher risk for heat-related illnesses?
A.They are older or have health problems. |
B.They are likely to sweat with little body fluids. |
C.They sweat more when they’re short of body fluids. |
D.They tend to lose body fluids when they sweat. |
9. What does the underlined word “
perspiring” in paragraph 2 mean?
A.Regulating. | B.Sweating. | C.Fainting. | D.Tiring. |
10. What is NOT a symptom of dehydration?
A.Lack of urination. | B.Lack of sleep. |
C.Extreme tiredness. | D.Dark-colored urine. |
11. Which of the following can be inferred from the passage?
A.Older people are more vulnerable to summer heat. |
B.Heat in summer is extremely dangerous for seniors. |
C.Older people should not work out outdoors in summer. |
D.Seniors have chronic medical conditions due to the heat wave. |