Aerobic-plus-resistance regimen boosts bone and muscles, study shows
By Kathleen Doheny
WEDNESDAY, May 17, 2017 (HealthDay News) -- Older, obese adults need to shed weight, but dieting can worsen their frailty. A new study addresses this conundrum, suggesting seniors take up both aerobic and resistance exercise while slimming down.
Engaging in aerobic and resistance exercise while losing weight enabled study participants to maintain more muscle mass and bone density compared to folks who did just one type of exercise or none at all, the researchers found.
"The best way to improve functional status and reverse frailty in older adults with obesity is by means of diet and regular exercise using a combination of resistance and aerobic exercise training," said study leader Dr. Dennis Villareal. He's a professor of medicine at Baylor College of Medicine in Houston.
More than one-third of people age 65 and older in the United States are obese, according to the study authors. Obesity worsens the typical age-related decline in physical functioning and causes frailty, while weight loss can lead to harmful declines in muscle mass and bone density.
The researchers wanted to see what combination of exercise, along with dieting for weight loss, might be best. They randomly assigned 160 obese and sedentary adults, age 65 or older, to one of four groups: weight loss and aerobic training; weight loss and resistance training; or weight loss and a combination of both types of exercise. The fourth group served as controls and didn't exercise or try to lose weight.
After six months, physical performance test scores increased by 21 percent in the combination exercise group, but just 14 percent among those who only did aerobic exercise or resistance exercise, Villareal's team said.
The researchers also found that lean body mass and bone density declined less in the combination and resistance groups than in the aerobic group.
One strength of the study is its evaluation of several regimens, said Miriam Nelson, director of the Sustainability Institute at the University of New Hampshire.
Such research is critical, as ''the majority of [older] people are either overweight or obese," said Nelson, who wasn't involved in the study.
While many studies of obese or overweight older adults focus only on exercise and weight loss, "this is really looking at health," she said.
"Health in aging is really [about] functioning," Nelson said. Maintaining muscle strength and bone density is essential to remain mobile and functional, she pointed out.
"All these multiple factors are what dictate to a large extent somebody's ability to be independent, healthy and to live life to its fullest as they age," Nelson added.
At the outset of the study, participants were mildly to moderately frail, according to the authors.
The researchers assessed the seniors' physical performance, muscle mass and bone health over the 26-week study.
The overall winners, the combination group, exercised three times a week, from 75 to 90 minutes each session.
Aerobic exercises included treadmill walking, stationary cycling and stair climbing. Resistance training involved upper-body and lower-body exercises on weight-lifting machines. All groups also did flexibility and balance exercises.
The study was published May 17 in the New England Journal of Medicine.
To learn more about exercise and older adults, see the U.S. National Institutes of Health.
SOURCES: Dennis T. Villareal, M.D., professor, medicine, Baylor College of Medicine, and staff physician, Michael E. DeBakey VA Medical Center, Houston; Miriam Nelson, director, Sustainability Institute, University of New Hampshire, Durham; May 17, 2017, New England Journal of Medicine
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