Is sitting too much dangerous for your health? Yes it is. There are a few health topics on which most doctors and health experts agree — and this is definitely one of them.
Now, a new Australian study led by the University of Sydney has found more evidence that sitting too much increases the risk of dying. This was even after taking into account physical activity, weight and health status of study participants. The study of more than 200,000 Australians is published in the March 26 issue of the Archives of Internal Medicine.
Relying on self-reported data from 22,497 people 45 years or older from the “45 and Up Study” — the largest look at healthy aging in the Southern Hemisphere — the researchers found that compared to people who spent less than four hours a day sitting:
• Adults who sat 11 or more hours a day had a 40 percent increased risk of dying in the next three years — from any cause.
• Adults who sat eight or more hours a day had a 40 percent increased risk of dying in the next three years — from any cause.
After ruling out other factors including age, gender, urban/rural residence, education, body mass index, smoking status, physical activity, disability and self-rated health, the Australian researchers determined that sitting was linked to a higher death risk.
“The evidence on the detrimental health effects of prolonged sitting has been building over the last few years,” study lead author Dr. Hidde van der Ploeg, a senior research fellow at the University of Sydney’s School of Public Health told HealthDay.
“The study stands out because of its large number of participants and the fact that it was one of the first that was able to look at total sitting time. Most of the evidence to date had been on the health risks of prolonged television viewing.”
But the researchers stressed that the self-reported data in the study didn’t prove sitting killed people — instead the findings suggest that there was a strong link between inactivity and mortality.
“These results have important public health implications,” says Dr. Van der Ploeg. “That morning walk or trip to the gym is still necessary, but it’s also important to avoid prolonged sitting. Our results suggest the time people spend sitting at home, at work and in traffic should be reduced by standing or walking more,” he says.
Van der Ploeg laments that nine out of 10 adults spend leisure time sitting down and fewer than half follow the standard set by the World Health Organization for exercise — which his, at least 150 minutes of at least moderate-intensity physical activity each week.
WHO says physical inactivity is the main cause for about 30 percent of ischemic heart disease burden, 27 percent of diabetes and about 21-25 percent of breast and colon cancers.
Even “for people who are regularly physically active, those who sit less have a lower risk of dying than those who sit more,” says Dr. Van der Ploeg.
“However, active people have a lower risk of dying compared to those who are physically inactive. So it’s still very important to meet the physical activity recommendations of 30 minutes per day of at least moderate intensity physical activities — such as walking — for adults and 60 minutes per day for children.”
Commissioned by the Cardiovascular Research Network and supported by the New South Wales Division of the National Heart Foundation Australia, the study is the first of landmark findings to be published from the Sax Institute’s 45 and Up Study– Australia’s richest information source about the health and lifestyles of people 45 and over. It’s one of more than 60 ongoing projects that use data from the 45 and Up Study. Such large-scale research will help governments face the challenges of an aging population.
Findings bolsters older studies
A study by Harvard researchers conducted last year found that spending at least two hours a day watching TV increases heart disease risk by 15 percent and type 2 diabetes risk by 20 percent, CBSNews.com’s HealthPop reports. TV watching for more than three hours daily raises the risk of dying from any disease, the study also found.
HealthPop also cited a meta-analysis that found too much sitting or a lack of physical activity has been linked to causing up to 43,000 cases of colon cancer and 49,000 cases of breast cancer. That analysis looked at over 200 studies from across the world and concluded that sitting down too much raises risks for cancer. It was presented at the American Institute for Cancer Research in Washington, D.C. in November 2011.
Dr. Alpa V. Patel, an epidemiologist at the American Cancer Society who has published studies on the health risks associated with too much sitting, tells WebMD that the new findings mean, “We are continuing to demonstrate time and time again in different populations that there’s something real to the association between sitting time and reduced longevity.”
How bad is too much sitting?
Very bad, it seems.
Commenting on a study she did last year, Dr. Patel said, “Prolonged time spent sitting — independent of physical activity — has been shown to have important metabolic consequences, and may influence things like triglycerides, high density lipoprotein, cholesterol, fasting plasma glucose, resting blood pressure and leptin.”
Diabetes and obesity
Sitting throughout most of the day raises the risk for diabetes, obesity and non-alcoholic fatty liver disease, according to an October 2011 study by University of Missouri researchers — even when they make time for daily exercise.
Raised heart attack risk
Scientists at the Pennington Biomedical Research Center in Louisiana analyzed the lifestyles of more than 17,000 men and women over about 13 years, and found that people who sit for most of the day are 54 percent more likely to die of heart attacks. The researchers found that sitting was an independent risk factor for serious cardiovascular events.
The gender angle
A study published in June 2011 in the American Journal of Epidemiology found that:
• Women who sat six or more hours a day were nearly 40 percent more likely to die over a 13-year-stretch than those who sat less than three hours.
• Men who sat for more than six hours had a nearly 18-percent higher risk of death.
The study, which followed 53,440 men and 69,776 women between 1993 and 2006 found that heart disease was linked more with the deaths than cancer was.
So what do you do if you’re chained to a 9-5 sitting job?
Okay, while we know that playing couch potato isn’t good for your health, some of us have to sit for a living. Writers, editors, illustrators, architects spend long hours on their creations — and mostly, they did this sitting down. So what can you do if your 9-to-5 job requires you be chained to your desk virtually the whole time?
The Australian researchers suggest that reducing sitting time — in addition to increasing physical activity levels — may help alleviate sitting’s link to all-cause mortality.
While at work, “try ways to break up your sitting and add in more standing or walking where possible. For example, try standing up while on the phone — or have a stand-up meeting,” says Dr. Van der Ploeg.
“Several workplaces in the Sydney area are trying sit-stand workstations, and they are generally well received, so this might be the future for workplaces,” he says.
Outside of work, it’s also important to sit less. “The average adult sits for 90 percent of their leisure time, so it seems there’s some room for improvement,” says Dr. Van der Ploeg. You don’t have to stand or walk for 100 percent of your leisure time of course, as sitting is very comfortable. But try to find a healthy balance between sitting, standing and walking or other physical activities.”
American Cancer Society’s Dr. Patel suggest people should sit for five fewer minutes each hour. “Small changes can have a big impact,” she says.