Long-distance runners may at tim

Long-distance runners may at times worry about their heart healthwhile taking part in the events. But astudy finds that heat stroke(中暑)fellsmany more runnersthan 76____ a heart problem.
Heat stroke can damage a person’s brain, heart, kidneys and 77____.And new data shows the toll it takes. Researchers 78____ health records frommore than 130,000 runners who competed in long-distance events during a seven-year span.Theanalysis 79____that distance runners were 10 times more 80____ to experienceheat stroke thanserious heart problems. All the fatal or life-threatening events were 81____heat stroke.
The researchersadvise runners to take 10 to 14 days to adjust to the climate 82____ takinga serious run in a hot region. And they sayrunners should 83____taking part in the event if they’ve been sick recently.
84____ one day runners will be installed some internal temperature controller that can keep their body temperature normal. But for now runners should simply 85____their best to keep cool.

81.____
A、 in
B、 of
C、 from
D、 on
【正确答案】：C