LA Times TV Watching

"The physical activity we do over a 24-hour period is important," says Dr. Gerald F. Fletcher, a cardiologist at the Mayo Clinic in Jacksonville, Fla., and a spokesman for the American Heart Assn.

People who watched more than four hours a day showed an 80% greater risk of death from cardiovascular disease and a 46% higher risk of all causes of death compared with those who watched fewer than two hours a day, suggesting that being sedentary could have general deleterious effects.

Researchers found that each hour a day spent watching TV was linked with an 18% greater risk of dying from cardiovascular disease, an 11% greater risk of all causes of death, and a 9% increased risk of death from cancer.

Researchers found a strong connection between TV hours and death from cardiovascular disease, not just among the overweight and obese, but among people who had a healthy weight and exercised.

Watching television for hour upon hour obviously isn't the best way to spend leisure time -- inactivity has been linked to obesity and heart disease.

Even sporadic exercisers who sit for long periods need to increase their daily activity.

People who watched more than four hours a day showed an 80% greater risk of death from cardiovascular disease and a 46% higher risk of all causes of death compared with those who watched fewer than two hours a day, suggesting that being sedentary could have general deleterious effects.

But a new study quantifies TV viewing's effect on risk of death.

"When we're in that sitting posture, we're not using our muscles, and we know from extensive evidence that muscle contractions are important for the body's regulatory processes, such as the ability to break down glucose and use it as energy."

That can cause insulin resistance, which can trigger a spike in blood sugar levels, possibly leading to type 2 diabetes.

"When we're in that sitting posture, we're not using our muscles, and we know from extensive evidence that muscle contractions are important for the body's regulatory processes, such as the ability to break down glucose and use it as energy."

He pointed out that muscles become deconditioned when not used, triggering harmful physiological changes.

"The message here is that in addition to promoting regular exercise, we also need to promote avoiding long periods of sitting, such as spending long hours in front of the computer screen."

Watching television for hour upon hour obviously isn't the best way to spend leisure time -- inactivity has been linked to obesity and heart disease.

Researchers found a strong connection between TV hours and death from cardiovascular disease, not just among the overweight and obese, but among people who had a healthy weight and exercised.

Watching television for hour upon hour obviously isn't the best way to spend leisure time -- inactivity has been linked to obesity and heart disease.

"For couch potatoes, sitting on your duff is hazardous to your health," Shah said.

Participants recorded their television viewing hours for a week, and researchers separated the results by amount of viewing: those who watched less than two hours of TV a day, those who watched two to four hours a day, and those who watched more than four hours a day.

"When we're in that sitting posture, we're not using our muscles, and we know from extensive evidence that muscle contractions are important for the body's regulatory processes, such as the ability to break down glucose and use it as energy."

"What we showed was that irrespective of a person's exercise level, sitting for four or more hours watching television was linked to a significant increase in risk of death compared to watching lower amounts of TV," said Dr. David Dunstan, lead author of the study and professor and head of the Physical Activity Laboratory at the Baker IDI Heart and Diabetes Institute in Victoria, Australia.