The article “Television Viewing Time and Mortality. The Australian Diabetes, Obesity and Lifestyle Study (AusDiab)” was published online on January 11, 2010, in the journal Circulation (a journal of the American Heart Association).
It is authored by David W. Dunstan, E. L.M. Barr, G. N. Healy, J. Salmon, J. E. Shaw, B. Balkau, D.J. Magliano, P. Z. Zimmet, and N. Owen (all from the Baker IDI Heart and Diabetes Institute, Melbourne, Australia); and A. J. Cameron (from the School of Exercise and Nutrition Sciences, Deakin University, Melbourne, Australia).
The Australian researchers state in the abstract to their paper: “Television viewing time, the predominant leisure-time sedentary behavior, is associated with biomarkers of cardiometabolic risk, but its relationship with mortality has not been studied.”
Consequently, they examined the relationship in Australian adults between watching TV for long periods of time and cardiovascular disease (CVD), cancer, and non-CVD/non-cancer mortality.
The researchers studied 8,800 adults (3,846 men and 4,954 women) over the age of twenty-five years who were taking part in the Australian Diabetes, Obesity and Lifestyle Study (AusDiab).
Over a 6.6 years period (between 1999 and 2006), the researchers found that 284 deaths occurred within the participants. Of this total number of death, 87 deaths occurred because of CVD and 125 from cancer.
They adjusted the results to take into consideration such external factors as gender, age, waist size and body mass index (BMI), exercise habits, blood pressure, blood cholesterol, diet, etc.
Page two shows the results of the study on TV watching for extended periods of time (or any sedentary activity such as sitting in front of a computer screen) and cardiovascular disease.
The researchers found that for every additional one-hour increment of television viewing time per day the participants had an 11% increased chance of dying prematurely from all causes (cardiovascular disease (CVD), cancer, and non-CVD/non-cancer).
Compared to people who watched TV less than two hours per day, the results for people who watched TV for two hours or more but less than four hours per day showed a mortality rate that increased 14% overall for all types of reasons.
For those people that watched TV over four hours per day, the mortality risk increased to 46% for all types of reasons.
For death caused by CVD, the rates increased to 19% (for those watching TV 2 hours to 4 hours per day) and 80% (for those watching TV for over four hours per day).
According to the American Heart Association press release “Sedentary TV time may cut life short,” the findings are applied to both obese/overweight people and normal weight people because “… prolonged periods of sitting have an unhealthy influence on blood sugar and blood fat levels.”
They concluded, “Television viewing time was associated with increased risk of all-cause and CVD mortality. In addition to the promotion of exercise, chronic disease prevention strategies could focus on reducing sitting time, particularly prolonged television viewing.” [Abstract]
Page three continues with additional quotes from the American Hearth Association press release.
The American Heart Association press release stated, “While the study focused specifically on television watching, the findings suggest that any prolonged sedentary behavior, such as sitting at a desk or in front of a computer, may pose a risk to one’s health.”
Dr. Dunstan stated within the article, “What has happened is that a lot of the normal activities of daily living that involved standing up and moving the muscles in the body have been converted to sitting.”
“Technological, social, and economic changes mean that people don’t move their muscles as much as they used to - consequently the levels of energy expenditure as people go about their lives continue to shrink.”
And, “For many people, on a daily basis they simply shift from one chair to another – from the chair in the car to the chair in the office to the chair in front of the television.”
He adds, “Even if someone has a healthy body weight, sitting for long periods of time still has an unhealthy influence on their blood sugar and blood fats.” [American Heart Association]
Dunstan concluded. “In addition to doing regular exercise, avoid sitting for prolonged periods and keep in mind to ‘move more, more often’. Too much sitting is bad for health.” [American Heart Association]
These results, although found in Australia, apply throughout the world, especially in the United States where people are exceedingly sedentary in their lifestyles.
Page four concludes with an article from the Baker IDI Heart and Diabetes Institute in Austalia, from which Dr. Dunstan is an associate.
The January 12, 2010 article "Watching TV Linked to Higher Risk of Death" from the Baker IDI Heart and Diabetes Institute discusses Dr. Dunstan's reseach.
"One of the most surprising findings is that it isn't just couch potatoes who were affected—even for people who exercised regularly, the risk of death went up the longer they were in front of the TV."
"The problem was the prolonged periods of time spent sitting still."
Dr. Dunstan states, "It's not the sweaty type of exercise we're losing. It's the incidental moving around, walking around, standing up and utilizing muscles that [doesn't happen] when we're plunked on a couch in front of a television."
The Baker IDI article goes into detail about how to add more activity to your life, which will help you to live longer.
For additional information on physical activity and its relationship to cardiovascular disease, please read the American Heart Association articles “Physical Activity” and “Physical Inactivity and CVD.”