[ti:Study: Resistance Exercise May Protect Bones in Overweight Elderly Adults] [by:www.51voa.com] [00:00.00]更多听力请访问51VOA.COM [00:01.16]What is the best form of exercise for older adults who are dieting? [00:08.32]Doctors do not yet know the answer. [00:11.52]But one study suggests that elderly dieters may be able to protect [00:18.40]against bone thinning by doing resistance exercise. [00:23.56]Medical experts often use body mass index, or BMI, [00:30.52]to measure obesity – the condition of being very overweight. [00:36.28]BMI compares a person's height and weight. [00:41.32]A BMI of around 30 or higher is considered obese. [00:48.24]Worldwide the number of obese people has nearly tripled since 1975, [00:55.72]notes the World Health Organization. [01:00.04]Obesity problems among older adults are difficult to deal with. [01:05.84]This is because weight loss efforts can create health problems, [01:11.16]such as an increased risk of bone thinning. [01:16.08]Thin bones are more likely to fracture, the study team noted. [01:21.64]Their findings appeared in The Journal of Bone and Mineral Research. [01:28.80]For the study, researchers randomly put 141 obese adults into one of four groups. [01:39.04]The first group had dieters who did only aerobic exercise. [01:45.80]The second group had dieters who only did resistance exercise. [01:52.92]The third had dieters who did both forms of exercise. [01:59.52]The final group, the control group, did not exercise or change their diet. [02:07.24]The subjects met with dieticians and did supervised workouts over 26 weeks. [02:15.04]The control group went to some classes to educate them about healthy eating. [02:22.40]All of the subjects in the study had a BMI of 30 or greater. [02:28.56]The average age was 70 years old. [02:33.36]In the exercise groups, subjects were given custom diets [02:38.48]that created a deficit of about 500 to 750 calories a day. [02:47.12]They also did supervised one-hour workouts three times a week. [02:54.16]The aerobic exercises included walking on an exercise machine, [03:00.00]riding a stationary bicycle, and stair climbing. [03:05.68]Resistance exercises included upper- and lower- body exercises using weight machines. [03:14.60]All of the exercisers also did some activities designed to improve balance and flexibility. [03:24.04]People in all three diet groups lost about 9% of their body weight during the study. [03:32.16]Members of the control group lost about 1% of their body weight. [03:37.92]At the end of the study, all of the participants had a decrease in bone density. [03:45.00]But bone density decreased less in the older adults who did resistance exercise. [03:54.16]Bone density also decreased less in those who did resistance exercise and aerobic workouts. [04:03.28]Doctor Dennis Villareal was the lead writer of a report on the study. [04:10.08]"When undergoing weight loss therapy," he said, elderly patients should use [04:16.20]"some resistance exercise to protect against bone loss." [04:21.56]"Resistance exercise should be at least moderate in intensity," Villareal added in an email. [04:30.28]"We do not know if less-intense exercise would be effective [04:35.56]in protecting against bone loss during weight loss." [04:40.72]Villareal is with the Baylor College of Medicine [04:44.88]and the Michael E. DeBakey VA Medical Center in Houston, Texas. [04:51.40]One limitation of the study is that researchers only followed the subjects for about six months. [05:00.52]That length of time is too brief to confirm whether one type of exercise [05:07.68]might be better than another for fall or bone fracture prevention, the report said. [05:15.44]Cynthia Brown is a doctor with the Integrative Center for Aging Research [05:21.76]at the University of Alabama at Birmingham. [05:26.60]"Based on this study, one would conclude that (for) an older adult [05:32.12]who is obese and trying to lose weight, the combination of aerobic and resistance exercise [05:40.68]will help the most to maintain their bone mineral density and their general physical fitness," she said by email. [05:49.76]"Older adults who are able should do muscle-strengthening exercises (resistance exercise) at least twice a week." [05:58.12]Brown was not involved in the study. [06:01.80]She also suggested that older adults with health issues [06:06.56]"make sure they understand how these conditions affect their ability to exercise." [06:13.64]She added that "all older adults should be as physically active as their abilities and conditions allow." [06:23.44]I'm John Russell. 更多听力请访问51VOA.COM