研究:抗阻运动对超重老年人骨骼的保护作用

What is the best form of exercise for older adults who are dieting?

Doctors do not yet know the answer. But one study suggests that elderly dieters may be able to protect against bone thinning by doing resistance exercise.

Obesity¹, BMI, and bone loss

Medical experts often use body mass index, or BMI, to measure obesity – the condition of being very overweight. BMI compares a person's height and weight. A BMI of around 30 or higher is considered obese².

Worldwide the number of obese people has nearly tripled since 1975, notes the World Health Organization.

Obesity problems among older adults are difficult to deal with. This is because weight loss efforts can create health problems, such as an increased risk of bone thinning. Thin bones are more likely to fracture, the study team noted³. Their findings appeared in The Journal of Bone and Mineral Research.

For the study, researchers randomly⁴ put 141 obese adults into one of four groups. The first group had dieters who did only aerobic⁵ exercise. The second group had dieters who only did resistance exercise. The third had dieters who did both forms of exercise. The final group, the control group, did not exercise or change their diet.

The subjects met with dieticians and did supervised workouts over 26 weeks.

The control group went to some classes to educate them about healthy eating.

All of the subjects in the study had a BMI of 30 or greater. The average age was 70 years old.

In the exercise groups, subjects were given custom diets that created a deficit⁶ of about 500 to 750 calories a day. They also did supervised one-hour workouts three times a week.

The aerobic exercises included walking on an exercise machine, riding a stationary⁷ bicycle, and stair climbing.

Resistance exercises included upper- and lower- body exercises using weight machines.

All of the exercisers also did some activities designed to improve balance and flexibility⁸.

People in all three diet groups lost about 9% of their body weight during the study. Members of the control group lost about 1% of their body weight.

At the end of the study, all of the participants had a decrease in bone density⁹. But bone density decreased less in the older adults who did resistance exercise. Bone density also decreased less in those who did resistance exercise and aerobic workouts.

Doctor Dennis Villareal was the lead writer of a report on the study.

"When undergoing weight loss therapy," he said, elderly patients should use "some resistance exercise to protect against bone loss."

"Resistance exercise should be at least moderate in intensity," Villareal added in an email. "We do not know if less-intense exercise would be effective in protecting against bone loss during weight loss."

Villareal is with the Baylor College of Medicine and the Michael E. DeBakey VA Medical Center in Houston, Texas.

Limitations and recommendations

One limitation of the study is that researchers only followed the subjects for about six months.

That length of time is too brief to confirm whether one type of exercise might be better than another for fall or bone fracture prevention, the report said.

Cynthia Brown is a doctor with the Integrative Center for Aging Research at the University of Alabama at Birmingham.

"Based on this study, one would conclude that (for) an older adult who is obese and trying to lose weight, the combination of aerobic and resistance exercise will help the most to maintain their bone mineral density and their general physical fitness," she said by email. "Older adults who are able should do muscle-strengthening exercises (resistance exercise) at least twice a week."

Brown was not involved in the study.

She also suggested that older adults with health issues "make sure they understand how these conditions affect their ability to exercise."

She added that "all older adults should be as physically¹⁰ active as their abilities and conditions allow."

Words in This Story

fracture – n. medical the result of breaking something

randomly - adv. chosen or done without a set plan

aerobic – adj. relating to or requiring free oxygen

workout – n. a period of physical exercise or training

stationary – adj. not designed to move

calorie – n. the energy needed to raise the temperature of one gram of water through 1 degree Celsius¹¹

flexibility – n. willingness to change or bend

conclude – v. to finish; to bring something to an end

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1 obesity   

n.肥胖，肥大

参考例句：

• One effect of overeating may be obesity.吃得过多能导致肥胖。
• Sugar and fat can more easily lead to obesity than some other foods.糖和脂肪比其他食物更容易导致肥胖。

2 obese   

adj.过度肥胖的，肥大的

参考例句：

• The old man is really obese,it can't be healthy.那位老人确实过于肥胖了，不能算是健康。
• Being obese and lazy is dangerous to health.又胖又懒危害健康。

3 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

4 randomly   

adv.随便地，未加计划地

参考例句：

• Within the hot gas chamber, molecules are moving randomly in all directions. 在灼热的气体燃烧室内，分子在各个方向上作无规运动。 来自辞典例句
• Transformed cells are loosely attached, rounded and randomly oriented. 转化细胞则不大贴壁、圆缩并呈杂乱分布。 来自辞典例句

5 aerobic   

adj.需氧的，增氧健身法的，有氧的

参考例句：

• Aerobic exercise helps to build up stamina.有氧健身操有助于增强耐力。
• Aerobic dance is conductive to the health.有氧舞蹈有助于健康。

6 deficit   

n.亏空，亏损；赤字，逆差

参考例句：

• The directors have reported a deficit of 2.5 million dollars.董事们报告赤字为250万美元。
• We have a great deficit this year.我们今年有很大亏损。

7 stationary   

adj.固定的，静止不动的

参考例句：

• A stationary object is easy to be aimed at.一个静止不动的物体是容易瞄准的。
• Wait until the bus is stationary before you get off.你要等公共汽车停稳了再下车。

8 flexibility   

n.柔韧性，弹性，（光的）折射性，灵活性

参考例句：

• Her great strength lies in her flexibility.她的优势在于她灵活变通。
• The flexibility of a man's muscles will lessen as he becomes old.人老了肌肉的柔韧性将降低。

9 density   

n.密集，密度，浓度

参考例句：

• The population density of that country is 685 per square mile.那个国家的人口密度为每平方英里685人。
• The region has a very high population density.该地区的人口密度很高。

10 physically   

adj.物质上，体格上，身体上，按自然规律

参考例句：

• He was out of sorts physically,as well as disordered mentally.他浑身不舒服，心绪也很乱。
• Every time I think about it I feel physically sick.一想起那件事我就感到极恶心。

11 Celsius   

adj.摄氏温度计的，摄氏的

参考例句：

• The temperature tonight will fall to seven degrees Celsius.今晚气温将下降到七摄氏度。
• The maximum temperature in July may be 36 degrees Celsius.七月份最高温度可能达到36摄氏度。