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(2022-新高考Ⅱ卷)As we age,.even if we're healthy,the heart just isn'tas
efficient in processing oxygen as it used to be.In most people the first signs show up in
their 50s or early 60s.And among people who don't exercise,the changes can start
even sooner.
"Think of a rubber band.In the beginning,it is flexible,but put it in a drawer for
20 years and it will become dry and easily broken,says Dr.Ben Levine,a heart
specialist at the University of Texas.That's what happens to the heart.Fortunately for
those in midlife,Levine is finding that even if you haven't been an enthusiastic
exerciser,getting in shape now may help improve your aging heart.
Levine and his research team selected volunteers aged between 45 and 64 who did
not exercise much but were otherwise healthy.Participants were randomly divided into
two groups.The first group participated in a program of nonaerobic (exercise-
balance training and weight training-three times a week.The second group did
high-intensity aerobic exercise under the guidance of a trainer for four or more days a
week.After two years,the second group saw remarkable improvements in heart health.
"We took these 50-year-old hearts and turned the clock back to 30-or
35-year-old hearts,"says Levine."And the reason they got so much stronger and
fitter was that their hearts could now fill a lot better and pump (a lot more blood
during exercise."But the hearts of those who participated in less intense exercise didn't
change,he says.
"The sweet spot in life to start exercising,if you haven't already,is in late
middle age when the heart still has flexibility,Levine says."We put healthy
70-year-olds through a yearlong exercise training program,and nothing happened to
them at all.”
Dr.Nieca Goldberg,a spokeswoman for the American Heart Association,says
Levine's findings are a great start.But the study was small and needs to be repeated
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