2022年高考英语阅读理解D深度解析全.docxVIP

2022年高考英语阅读理解D深度解析(名校内部资料) D As we age, even if were healthy, the heart just isnt as 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. Thats what happens to the heart. Fortunately for those in midlife, Levine is finding that even if you havent 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 (无氧) 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 (泵送) 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 havent 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 with far larger groups of people to determine exactly which aspec