An increasing percentage of Americans aged 65 or more years have been spending time sitting at computers outside of any work or school commitments, according to the results of a study released Tuesday by JAMA, the journal of the American Medical Association.

This is despite public health messages that such inactivity increases the risk of diabetes, heart disease, certain cancers and other illnesses, researchers said.

The investigative team, led by researchers at Washington University School of Medicine in St. Louis, analyzed surveys of 51,000 people from 2001 to 2016 to track sitting trends in front of TVs and computers and the total amount of time spent sitting on a daily basis. The researchers believe the study is the first to document sitting in a nationally representative sample of the U.S. population across multiple age groups — from children to the elderly — as well as different racial and ethnic groups.

They found that in 2003-2004, 15.4% of older adults spent an hour or more per day in front of the computer. By 2015-2016, the most recent year studied, 53.4% of adults aged 65 or more years were spending at least an hour a day in front of the computer.

The percentage of older adults spending two or more hours per day in front of the television has remained relatively stable over the course of the study, going from 80.6% in 2003-2004 to 84.1% in 2015-2016.

Overall, the researchers found, those aged 65 or more years sit about 6.1 hours per day.

“In almost none of the groups we analyzed are the numbers going in the right direction,” said Yin Cao, Sc.D., an epidemiologist and assistant professor of surgery and the study’s senior author. “We want to raise awareness about this issue on multiple levels — from individuals and families to schools, employers and elected officials.

A separate study by researchers in Australia, Norway and the United Kingdom published in the Journal of the American College of Cardiology offers some hope for health, however, finding that increasing physical activity to recommended levels may eliminate the association between sitting and an increased risk of death in some people.

Meeting even the lowest requirements for physical activity (150 to 299 minutes per week) eliminated the association with all-cause mortality risk, with the exception of those who sat more than eight hours a day.

The researchers recommended substituting brisk walking for sitting, recognizing, however, that not all adults will be able to do so.

“Given that sedentary behaviors appear to be vastly out-competing more healthy physical activity behaviors during our discretionary time, it is more important than ever to attend to our daily physical activity and sitting time to try to optimize both behaviors for better health,” Charles E. Matthews, Ph.D., physical activity epidemiologist and investigator at the National Cancer Institute, wrote in an accompanying editorial.