The benefits of regular exercise are well documented but there's a new bonus to add to the ever-growing list. New researchers found that middle-aged women who were physically fit could be nearly 90 percent less likely to develop dementia (失智症) in later life and is they did, it came on a decade later than less sporty women.

Lead researcher Dr. Helena Horder, of the University of Gothenburg in Sweden, said: "These findings are exciting because it's possible that improving people's cardiovascular (心血管的) fitness in middle age could delay or even prevent them from developing dementia."

For the study, 191 women with an average age of 50 took a bicycle exercise test until they were exhausted to measure their peak (最大值的) cardiovascular capacity. The average peak workload was measured at 103 watts. A total of 40 women met the criteria for a high fitness level, or 120 watts or higher.

A total of 92 women were in the medium fitness category: and 59 women were in the low fitness category, defined as a peak workload of 80 watts or less, or having their exercise tests stopped because of high blood pressure, chest pain or other cardiovascular problems.

These women were then tested for dementia six times over the following four decades. During that time, 44 of the women developed dementia. Five percent of the highly fit women developed dementia, compared to 25 percent of the women with medium fitness and 32 percent of the women with low fitness

"However, this study does not show cause and effect between cardiovascular fitness and dementia it only shows an association. More research is needed to see if improved fitness could have a positive effect on the risk of dementia and also to look at when during a lifetime a high fitness level is most important" She also admitted that a relatively small number of women were studied, all of whom were form Sweden so the results might not be applicable to other groups.

As we age, even if we're healthy, the heart just isn't 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. 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 (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 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 with far larger groups of people to determine exactly which aspects of an exercise routine make the biggest difference.

POETRY CHALLENGE

    Write a poem about how courage, determination, and strength have helped you face challenges in your life.

Prizes

    3 Grand Prizes: Trip to Washington, D.C. for each of three winners, a parent and one other person of the winner's choice. Trip includes round-trip air tickets, hotel stay for two nights, and tours of the National Air and Space Museum and the office of National Geographic World.

    6 First Prizes: The book Sky Pioneer:A Photobiography of Amelia Earhart signed by author Corinne Szabo and pilot Linda Finch.

    50 Honorable Mentions:Judges will choose up to 50 honorable mention winners, who will each receive a T-shirt in memory of Earhart's final flight.

Rules

    Follow all rules carefully to prevent disqualification.

    ■Write a poem using 100 words or fewer. Your poem can be any format, any number of lines.

    ■Write by hand or type on a single sheet of paper. You may use both the front and back of the paper.

    ■On the same sheet of paper, write or type your name, address, telephone number, and birth date.

    ■Mail your entry to us by October 31 this year.