Cigarette packs carry health-hazard warnings; some experts suggest TVs, computers, smartphones, and tablets be emblazoned with this: “Sedentary behavior experienced using this device can cause an increased risk of type 2 diabetes and related health problems.”
But what exactly does sedentary behavior mean?
“It is simply all the activities you do when you’re awake in a sitting or reclined position,” says Dale Bond, Ph.D., associate professor of psychiatry and human behavior at the Brown University Weight Control and Diabetes Research Center in Providence, Rhode Island. He says sedentary behavior occurs anytime you expend a low level of energy and burn minimal calories.
But being sedentary is not the same as being inactive. You can meet daily activity goals but also be highly sedentary, Bond says.
In other words, reducing sitting time is a third type of activity to incorporate into your daily life. The other two are aerobic exercise and resistance training. Research shows that regularly hitting these three goals is well worth the effort when it comes to your health.
What we know
Evidence of the perilous effects of sedentary behavior began in the 1950s, when researchers found that men in physically active jobs experienced less heart disease when they became middle aged, says Len Kravitz, Ph.D., associate professor of exercise science at the University of New Mexico in Albuquerque.
Sitting for long periods on a daily basis can increase the risk factors associated with type 2 diabetes and heart and blood vessel diseases, including elevated triglycerides, low HDL (good) cholesterol, decreased insulin sensitivity, increased insulin resistance, rising glucose levels, increased waist circumference (inches around the waist), and excess abdominal fat. Kravitz adds to this list higher rates of breast and colon cancers and mental health problems.
Sedentary behavior lowers the amount of a critical enzyme made by the muscles, he says. This can increase triglycerides and decrease HDL cholesterol levels, preventing HDLs from doing their job of scavenging and getting rid of cholesterol before it builds up plaque on blood vessel walls.
Low levels of this enzyme also decrease the glucose in the blood that muscles can use, the primary connection between sedentary behavior and type 2 diabetes.
by Hope Warshaw, RD, CDE