(Reuters) - People who spent a lot of time sitting at a desk or in front of a television were more likely to die than those who were only sedentary a few hours a day, according to an Australian study that looked at death rates during a three-year period.
Researchers, whose results appeared in the Archives of Internal Medicine, found that the link between too much time sitting and shortened lives stuck even when they accounted for how much moderate or vigorous exercise people got, as well as their weight and other measures of health.
That suggests that shifting some time from sitting to light physical activity, such as slow walking or active chores, might have important long-term benefits, they added.
"When we give people messages about how much physical activity they should be doing, we also need to talk to them about reducing the amount of hours they spend sitting each day," said Hidde van der Ploeg, the new study's lead author from the University of Sydney.
Of more than 200,000 adults age 45 and older, van der Ploeg and her colleagues found that people who reported sitting for at least 11 hours a day were 40 percent more likely to die during the study than those who sat less than four hours daily.
That doesn't, however, prove that sitting itself cuts people's lives short, she noted, adding that there could be other unmeasured differences between people who spend a lot or a little time sitting each day.
The team surveyed about 220,000 people from New South Wales, Australia, between 2006 and 2008, including questions about participants' general health and any medical conditions they had, whether they smoked and how much time they spent both exercising and sitting each day.
Then the research team tracked responders using Australian mortality records for an average of almost three years, during which 5,400 - between two and three percent - died.
They found that the extra risk tied to sitting held up regardless of whether people were normal weight or overweight, how much time they spent working out and whether they were healthy or had pre-existing medical conditions.
Van der Ploeg said too much sitting may affect blood vessels and metabolism by increasing fats in the blood and lowering "good" cholesterol levels.
"When you are standing or walking, your leg muscles are constantly working which helps to clear blood glucose and blood fats from the blood stream," she said. "If you are sitting, this is not happening because the muscles are not active."
The findings are consistent with other recent studies suggesting health consequences from too much sitting, said Mark Tremblay, an obesity and activity researcher at Children's Hospital of Eastern Ontario in Canada.
"Sitting or reclining, especially in front of screens, is bad for you regardless of your age," said Tremblay, who wasn't involved in the study.
He added that even though people tend to think they're okay as long as they work out a certain amount a day, that's not necessarily the case.
"Getting your 30 minutes of physical activity five times a week is not insurance against chronic disease.
Both he and Van der Ploeg said there were ways that even people who have jobs involving a lot of desk work can train themselves to regularly interrupt sedentary behavior, such as standing up while on the phone or holding a stand-up meeting.
"Make sure the fax machine is four steps away from you, not within reaching distance," Tremblay said.
"Drink enough water that you have to pee four times a day. Stand up, stretch, walk around a little bit, say 'hi' to your friend in the cubicle next door." SOURCE: bit.ly/Hi0niK (Reporting from New York by Genevra Pittman at Reuters Health; editing by Elaine Lies)
WebMD Health News Reviewed by Louise Chang, MD
March 26, 2012 -- Don't take this sitting down, but spending too much time in a chair is bad for your health really, really bad.
New research published in the Archives of Internal Medicine shows that people who spend a lot of time sitting may be up to 40% more likely to die from any cause, compared to people who don't sit as long.
The study tracked nearly 222,500 Australian adults for about three years. During that time, people's odds of dying dovetailed with how much time they spent sitting.
Compared to people who spent less than four hours per day sitting, the odds of dying were:
15% higher for people who sat for at least eight hours
40% higher for people who sat for 11 or more hours a day
"Our findings add to the mounting evidence that public health programs should focus not just on increasing population physical activity levels, but also on reducing sitting time, the researchers write.
Alpa V. Patel, PhD, has published studies on the health risks associated with too much sitting. She is an epidemiologist at the American Cancer Society in Atlanta. "We are continuing to demonstrate time and time again in different populations that there is something real to the association between sitting time and reduced longevity."
Get Up Out of That Chair
What's so bad about sitting for long periods? That's not totally clear. But exercise and movement do have a positive effect on blood fats called triglycerides and other heart risks, and improves blood pressure, Patel says.
Her advice: Sit for five fewer minutes per hour. "Small changes can have a big impact," she says.
Technology may fight that. It's given us fewer reasons to move, says David A. Friedman, MD. He is the chief of heart failure services at North Shore Plainview Hospital in Plainview, N.Y.
Instead of texting or emailing a colleague, "walk down a few cubicles and say, 'Hi, how are you?' This is good face time and it's also good exercise."
Olveen Carrasquillo, MD, MPH, is the chief of the division of general internal medicine at the University of Miami's Miller School of Medicine. "A sedentary lifestyle is not good for your health," he says. "Today we don't even have to leave the house to go to the bank or mail a letter."
The new study doesn't prove that sitting killed people. It's not clear which came first -- poorer health or spending more time in a chair.
Still, there's no doubt that movement is good for many reasons.
"It is hard to say whether someone is fairly sedentary because they are inactive or if they are inactive because of other things, such as an unhealthy lifestyle that includes smoking," says Scott Kahan, MD, MPH. He is the director of the National Center for Weight and Wellness in Washington, D.C.
Still, there is no doubt that being active is healthy. "The key is to do something you like to do, whether it's sports, going to the gym, walking, or gardening. "If it is terribly unenjoyable, the likelihood of sustaining it is pretty low."
Sitting risks: How harmful is too much sitting?
What are the risks of sitting too much?
from James A. Levine, M.D., Ph.D.
Researchers have linked sitting for long periods of time with a number of health concerns, including obesity and metabolic syndrome a cluster of conditions that includes increased blood pressure, high blood sugar, excess body fat around the waist and abnormal cholesterol levels.
Too much sitting also seems to increase the risk of death from cardiovascular disease and cancer.
One recent study compared adults who spent less than two hours a day in front of the TV or other screen-based entertainment with those who logged more than four hours a day of recreational screen time. Those with greater screen time had:
A nearly 50 percent increased risk of death from any cause About a 125 percent increased risk of events associated with cardiovascular disease, such as chest pain (angina) or heart attack The increased risk was separate from other traditional risk factors for cardiovascular disease, such as smoking or high blood pressure.
Sitting in front of the TV isn't the only concern. Any extended sitting such as behind a desk at work or behind the wheel can be harmful. What's more, spending a few hours a week at the gym or otherwise engaged in moderate or vigorous activity doesn't seem to significantly offset the risk.
Rather, the solution seems to be less sitting and more moving overall. You might start by simply standing rather than sitting whenever you have the chance.
Stand while talking on the phone or eating lunch. If you work at a desk for long periods of time, try a standing desk or improvise with a high table or counter.Better yet, think about ways to walk while you work:
Walk laps with your colleagues rather than gathering in a conference room for meetings.
Position your work surface above a treadmill with a computer screen and keyboard on a stand or a specialized treadmill-ready vertical desk so that you can be in motion throughout the day.
The impact of movement even leisurely movement can be profound. For starters, you'll burn more calories. This might lead to weight loss and increased energy.
Even better, the muscle activity needed for standing and other movement seems to trigger important processes related to the breakdown of fats and sugars within the body. When you sit, these processes stall and your health risks increase. When you're standing or actively moving, you kick the processes back into action.