It's not enough for people to get regular moderate exercise as they age. Researchers say it's also important not to spend the rest your time sitting too much.
In fact, for every hour of sedentary behavior, the odds were 46% greater that people older than 60 would have some disability in ordinary skills such as getting around the house and feeding themselves, according to the study published Wednesday in the Journal of Physical Activity & Health.
Being sedentary will lead to problems "independent of time spent in moderate or vigorous activity," concluded the researchers, from Northwestern's Feinberg Medical School, Rush University Medical Center, Harvard School of Public Health and the Centers for Disease Control and Prevention.
People who replace even half an hour of sedentary time with 30 minutes of light activity can improve their health, researchers said. Stand-up bingo, anyone?
"A sedentary lifestyle is associated with a variety of poor health outcomes, including increased incidence for diabetes, cardiovascular disease and mortality," the researchers wrote. But many people may have thought they'd done what they needed to if they met the government suggestion of 150 minutes a week of moderate activity.
Apparently not so.
The question was whether people were sedentary because they were not doing any exercise, or whether being sedentary was on its own a risk factor for disability in what are called activities of daily living – getting in and out of bed, getting dressed, being able to walk in the house
The researchers used data from the National Health and Nutrition Examination Surveys from 2003 to 2005. Those data are a nationwide collection that includes questionnaires and physical exams, and they included 2,286 people 60 and older whose physical activity had been monitored.
The people in that sample spent almost nine waking hours a day sedentary, and 3.6% of them reported disability in their activities of daily living. The average waking time was 14 hours.
About 12% of them reported no chronic conditions. Fifty-two percent reported arthritis, 58% reported hypertension and 30% reported obesity. Being sedentary longer hours was related to older age, being male, being more educated and less wealthy, being a smoker and having a chronic illness.
Sitting has been getting a lot of attention lately, to the point that there's a new adage: "Sitting is the new smoking." In addition to encouraging everyone to sit less, people are specifically encouraging exercises during TV watching and during work hours, with walking meetings and standing desks, as ways to decrease sedentary time.
"The real problem is that we are raising sedentary children," said one of the researchers, Pamela Semanik, assistant professor of adult and gerontological nursing at Rush College of Nursing. "It's so insidious in our culture."
At her workplace, where people see the results of not moving, people have changed their ways, she said, adding that she has sold her car and reads medical journal articles on a treadmill.
The researchers in the current study said as many as 5.3 million annual deaths worldwide are related to insufficient activity.
So how much coach potato time is OK?
"That's the $64,000 question," Semanik said. "We don't know how much is OK." She said researchers suspect that one way to mitigate the harm of being sedentary is with frequent breaks to move around.
Their work, they said, appears to be the first to document objectively sedentary time and its relation to disability in activities of daily living, independent of exercise time. One limit of the research is that the gadgets used to monitor activity, called accelerometers, don't detect such movements as cycling and were not worn for swimming.
The research supports programs that would get people to spend less time sitting, regardless of what exercises they do. "Among some older adults, reducing sedentary behavior may be a more attainable goal than increasing moderate-vigorous activity, particularly in persons with chronic illness, pain, and those with pre-existing disabilities," the researchers wrote.
That's not to suggest there's no value in moderate exercise, which they said is an inexpensive way to be healthier and reduce healthcare costs. But the current study is looking "at a very different question," which is how people stay independent, out of nursing homes and able to fend for themselves, Semanik said.
But they wrote, "Even a large daily dose of moderate-vigorous activity may not be sufficient to offset the adverse effects of a sedentary lifestyle."
As Semanik put it: "Just get up and move."