(CNN) - A new study published in the Journal of The American Medical Association shows the time people spend sitting in front of computers is rising dramatically.
From 2001 to 2016, leisure computer use rose between about five percent and 38 percent - depending on how old you are.
The study says 43 percent of Americans now use a computer for at least two hours a day. A quarter of us use one for at least three hours.
The end result is teens spend about 8.2 hours sitting each day, and adults sit for about 6.4.
Sedentary behavior is known to contribute to obesity, heart disease, diabetes and cancer.
“Research evidence has been growing on the association between sedentary behavior -- primarily TV watching -- and a variety of diseases, including obesity, cardiovascular disease, cancer, Type 2 diabetes and overall mortality,” said Yin Cao, senior author of the new study and an assistant professor of surgery at Washington University School of Medicine in St. Louis.
The good news is cardiologists say even short breaks of light physical activity can help offset the increased risk of heart disease.
Of course, longer more intense activity is better, but any activity is better than none.
About 65 percent of the population reports watching at least two hours of TV a day - but experts say that number hasn’t grown over the past 15 years.