CHICAGO -- Heavy seniors who want to lose pounds safely shouldn't skip the weight machines or the treadmill, new research suggests.
Experts have worried about recommending weight loss to older, obese people because it speeds up bone and muscle loss, increasing the danger of falls and broken bones. Losing weight plus aerobic activity and strength training improved their health more than dieting plus either type of exercise alone.
The results suggest a combination of exercises is the safest approach, and may have big implications for helping people continue to live independently as they age. Medicare, the U.S. health insurance program for people 65 and older, now covers behavioural therapy for weight loss and some plans offer gym memberships.
"It is the worst of both worlds, being fat and frail," said Dr. Dennis T. Villareal of Baylor College of Medicine in Houston, who led the study under a grant from the National Institute on Aging.
More than a third of Americans ages 65 and older are obese. Obesity can make the elderly vulnerable to medical problems, but losing weight can worsen frailty by hastening muscle and bone loss.
The study, published Wednesday by the New England Journal of Medicine, involved 141 older obese people who were randomly assigned to a diet-and-exercise program. They scored in the frail range on a standard test used with seniors.
One group did aerobics such as treadmill walking. Another did strength training with weight machines. A third group did aerobics and strength training. All exercised three times a week.
A control group didn't diet or exercise and only attended monthly nutrition classes.
After six months, all the groups -- except the do-nothing group -- had lost weight, about 19 pounds on average.
The combination and aerobics-only groups built their ability to use oxygen most efficiently, which can increase endurance. The combination and strength-only groups preserved the most lean mass and bone.
The health differences showed up in follow-up testing where participants did a series of nine tasks including picking up a penny, standing up from a chair and climbing stairs.
Most improved was the combination group with a 21 per cent average increase in scores compared to 14 per cent improvement in the aerobics-only and strength-only groups.
"It's never too late to change lifelong unhealthy habits," Villareal said.
Minor injuries such as knee pain and shoulder pain among the exercisers were not enough to outweigh the benefits, he said.
The study excluded people with severe heart disease and other serious health problems, so the results apply only to people well enough to start an exercise program.
"You get more bang for your buck with doing both types of training, especially when it comes to improving frailty scores," said Dr. Lawrence Appel of Johns Hopkins University, who was not involved in the study.