Sitting for extended periods daily can lead to chronic kidney disease, according to medical investigators who examined how the cumulative effects of remaining seated can carry long-term risks.
The new research by a team of British investigators arrived at that conclusion by asking more than 6,000 participants to perform some simple math: add up the amount of time each spent sitting on an average weekday.
Reporting in the October issue of the American Journal of Kidney Diseases, investigators were able to divide people into three groups: those at highest risk who sat 8 or more hours a day; people at moderate risk who stayed seated at least 3.2 to 7.8, and those at low risk who sat 0 to 3 hours.
Tom Manley, director of scientific activities for the National Kidney Foundation, said the research provided more than a statistical link between sitting and chronic kidney disease. Researchers, Manley said, measured the organ's ability to filter wastes and tested urine for high levels of a telltale protein -- albumin -- an indicator of poor kidney function. Those who sat for longer periods had higher albumin levels.
"The surprise in this study is that sitting is directly related to kidney disease," said Manley, a registered nurse. "A sedentary lifestyle has been linked to hypertension and cardiovascular disease. Now we see that it [sitting] has broader health risks.
"But what this also tells us is that this is a modifiable risk factor. There's something you can do about it -- get out of that chair," Manley said.
As twin organs in the rear of the abdominal cavity, the kidneys have multiple physiological functions, including regulating blood pressure, filtering wastes, and producing hormones and urine.
Dr. Steven Fishbane, vice president for Network Dialysis Services at the North Shore-Long Island Jewish Health System, noted the study's results should be taken with a dose of caution.
"We should never conclude from this that people should give up their office jobs," Fishbane said.
"If you have a job where you are sitting seven hours a day, you have to take your health into your own hands. You have to make certain that you're getting up and moving around.
"If companies care about their employees' health, they should make certain that employees are getting up a couple of times a day, spending it walking, stretching, moving around."
Noted in the research were people who spent most of their day standing, which Manley emphasized correlated with a lower rate of chronic kidney disease.
"Just being upright is a good thing for kidney health," Manley said, adding that sitting for extended periods has long been related to the development of blood clots in the legs -- deep vein thrombosis -- which some people develop after sitting for hours on an airplane.