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再细看一下这个公式当时推导的有多么草率:
”In preparation for a medical meeting , Dr. Haskell culled data from about 10 published studies in which people of different ages had been tested to find their maximum heart rates.
The subjects were never meant to be a representative sample of the population, said Dr. Haskell, who is now a professor of medicine at Stanford. Most were under 55 and some were smokers or had heart disease.
On an airplane traveling to the meeting, Dr. Haskell pulled out his data and showed them to Dr. Fox. ''We drew a line through the points and I said, 'Gee, if you extrapolate that out it looks like at age 20, the heart rate maximum is 200 and at age 40 it's 180 and at age 60 it's 160,'' Dr. Haskell said.
At that point, Dr. Fox suggested a formula: maximum heart rate equals 220 minus age.
But, exercise physiologists said, these data, like virtually all exercise data, had limitations. They relied on volunteers who most likely were not representative of the general population. ''It's whoever came in the door,'' Dr. Kirkendall said.
In addition, he and others said, gauging maximum heart rates for people who are not used to exercising is often difficult because many prematurely stop the test.
As the treadmill hills get steeper, people who are not used to exercise will notice that their calves are aching. ''They will say they can't go any further,'' Dr. Kirkendall said.
In addition, Dr. Wilmore, the exercise physiologist, said it was clear from the scattered data points that maximum heart rates could vary widely from the formula. ''If it says 150, it could be 180 and it could be 120,'' Dr. Wilmore said.
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在一架飞机上,顺便选了先前测量的任何碰巧上门的自愿者的心率,其中包括吸烟者,有心脏病的. 随手在一张纸上画了条线,得出这个公式以讹传讹40年。 |
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