Newsday, Melville, N.Y., 07-12-06
Elderly people who expended more energy in their day-to-day routine, running errands and doing household chores, lived longer than those with more sedentary lifestyles, according to a new study.
A third of the 302 volunteers, those who engaged in little physical activity, died on average about six years sooner than more active participants, according to the study published today in the Journal of the American Medical Association.
Participants in the highest activity group had a 67 percent lower risk of death than people in the lowest activity group after adjusting for behaviors like smoking, existing medical conditions and demographic factors, according to Todd Manini, the lead author and an exercise physiologist.
"The public health message is simple: Expending energy can help lower your risk of death," said Manini, a research scientist at the National Institute on Aging, which conducted the study. "It is appealing for many older adults, because sometimes they are intimidated by exercise or going to the gym. If you just use energy throughout the day, doing it will help protect against the risk of death."
The highest-activity groups reported holding paying jobs and climbing an average of two more flights of stairs per day than the inactive group.
Surprisingly, Manini said, participants in the highest and lowest groups reported similar amounts of walking.
"We don't want to suggest that people should stop exercising," Manini said, but rather that there are multiple ways to be effectively active.
Margaret Hawkins, manager of health promotions for AARP, said, "We encourage people over 50 to be more active during the course of their day by doing usual things like parking farther away from the store or taking the stairs instead of the elevator."
Fifty-five people died during the study. Those who lived longer burned about 600 more calories a day. Manini said future research would use pedometers, which measure the steps a person takes, to help zero in on how the extra calories were burned.
The eight-year study is believed to be the first to use a specific, objective measurement of energy expenditure using heavy water to determine whether "free-living" or the amount of normal daily activity is related to longevity.
Beginning in 1998, the elderly adults drank the specially formulated water that was measured in their body at the start and two weeks later. The amount of energy burned by the participants, aged 70-82, was measured by the amount of isotopes the heavy water left in the body.
"When they drink this water, it goes into every compartment of the body just like normal water, but it is only released from the body as carbon dioxide," Manini said.
Previous studies have shown that people who report high levels of physical activity have lower risk of death. But "the problem with questionnaires are they are fraught with inaccuracy because participants do not remember how much they exercised or are more likely to deny not exercising," said Dr. Gisele Wolf-Klein, chief of geriatric medicine at Long Island Jewish Medical Center in New Hyde Park. "The approach used for this study is the gold standard in terms of the strength of the study."
This study is part of the 10-year Health, Aging and Body Composition Study sponsored by the National Institutes of Health, slated to culminate next year. This type of study is rarely done because of the expense and time involved examining the samples. The heavy water is estimated at about $300 per patient with lab costs about $1,000 per patient.
Copyright (c) 2006, Newsday, Melville, N.Y.
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