A study published recently by the American Journal of Preventive Medicine has linked TV viewing to a greater risk of dying from eight out of 14 of the leading causes of death in the United States. These include coronary heart disease, cancer, COPD, diabetes, influenza, pneumonia, Parkinson’s disease, liver disease, and suicide.
The researchers, headed by Dr. Sarah K. Keadle of the National Cancer Institute, controlled for confounding factors which could be partly responsible for the results, such as BMI, caloric and alcohol intake, smoking, overall health status, and so on, but the association between prolonged TV viewing and increased mortality remained. The association was even detected in those who were physically active on a regular basis, reports Forbes.
We know that television viewing is the most prevalent leisure-time sedentary behavior, and our working hypothesis is that it is an indicator of overall physical inactivity.
“Although we found that exercise did not fully eliminate risks associated with prolonged television viewing, certainly for those who want to reduce their sedentary television viewing, exercise should be the first choice to replace that previously inactive time,” says Keadle.
The study followed 221,000 healthy, disease-free adults between the ages of 50-71. The health of each adult was tracked from 1995 until their death or until December 31, 2011 — whichever came first. Risk of death from the eight diseases previously mentioned began to increase with three to four hours of TV viewing per day. Those who watched seven or more hours of television per day showed a 47% increase in mortality associated with the eight diseases.
“We know that television viewing is the most prevalent leisure-time sedentary behavior, and our working hypothesis is that it is an indicator of overall physical inactivity,” says Keadle. “In this context, our results fit within a growing body of research indicating that too much sitting can have many different adverse health effects.”
More research is needed, especially since past studies, as mentioned in Medical News Today, have shown no significant deleterious effects of prolonged TV viewing. All told, the majority of research on the subject shows clear links between a sedentary lifestyle and increased mortality. Previous studies have shown that prolonged TV viewing is linked with increased risk of dying from cancer and cardiovascular disease. The research done by Keadle and her team confirms these links, and adds new ones.
Some mechanisms behind the connection between prolonged TV viewing and poor health may include changes in insulin levels, an increase in inflammatory markers, poor overall cardiovascular and respiratory health, and poor muscle strength. These factors could play a role in being unable to withstand age-related health problems, though more research is needed to shed light on the exact causes.
The study concludes: ”Older adults watch the most TV of any demographic group in the US. Given the increasing age of the population, the high prevalence of TV viewing in leisure time, and the broad range of mortality outcomes for which risk appears to be increased, prolonged TV viewing may be a more important target for public health intervention than previously recognized.”