Is Sitting All Day Going to Kill Me?
I could die in an airplane crash. I could get killed in a car accident. I could get shot in the street. I could get mauled by a shark in the ocean. Bears could eat me in the woods. I could be kidnapped, held for ransom, and murdered overseas. Or perish in a club fire. I could be blown up by terrorists. My parachute could fail to open. My boat could sink. My motorcycle could crash. I could forget to look both ways while crossing the road and -- splat!
There are so many ways to die out there, but I can always avoid an untimely end by staying home and sitting on my couch. Right? Right?!?
A very wise man -- Mr. Burns from “The Simpsons” -- once said, "Sitting -- the great leveler. From the mightiest pharaoh to the lowliest peasant, who doesn't enjoy a good sit?"
Me. I no longer enjoy a good sit. I’m afraid I’ll keel over every time I spend more than 20 minutes in a chair.
Have you read the headlines?
“Is Sitting a Lethal Activity?” -- New York Times
“Sitting for More Than Three Hours a Day Cuts Life Expectancy” -- Wall Street Journal
“Is Your Office Chair Killing You?” -- Men’s Health
“Why Sitting All Day is Killing You” -- CBS News
“7 Ways Sitting Will Kill You” -- Popular Science
“All of Our Editors Died This Morning” -- Sitting Illustrated
OK, that last one is made up, but if there was a Sitting Illustrated -- and the lack of one is capitalism’s greatest failure -- that particular publication would likely be in trouble right now.
Sitting, I love you. You’re one of my favorite things I can do with my body. Are you trying to kill me?
The Chair Scare
The last few years have seen a surge of sitting-related research so frightening it has physically knocked people out of their chairs. The standing-desk trend is sweeping offices nationwide. Maybe you have a stander in your office. You probably make fun of him behind his back, but will he have the last laugh standing over your casket at your funeral?
The research says yes -- yes, he will.
There is a strong association between sitting and chronic disease. The key word in that sentence is association. No one can say definitively that sitting is a cause of poor health. There is much we don’t know when it comes to sitting and health.
Inactivity physiology -- the study of what the body does when it’s doing nothing -- is a relatively new field. Richard Rosenkranz, assistant professor in Kansas State University's department of human nutrition, calls it “unexplored terrain that’s being carved out in a hurry.” The recent spate of research was born from work that Pennington Biomedical Research Center professor Marc Hamilton and his colleagues did on rats during the last two decades. Their research laid the groundwork for the large-scale studies involving humans, which have received so much attention in mainstream publications.
One of those studies on humans was conducted by Hidde Van Der Ploeg, senior research fellow at the University of Sydney’s Sydney School of Public Health. His team looked at data collected from 200,000 Australians. It found that adults who sat for 11 hours per day or longer had a 40 percent increased risk of dying over the next three years -- compared to people who sat for fewer than four hours a day.
“We think that prolonged sitting is bad for your cardiovascular and metabolic health,” Van Der Ploeg said. “It seems to be bad for your ACL cholesterol, your triglyceride levels and insulin sensitivity.”
What’s the physiological explanation for this?
No one knows.
When I put the question to Craig Harms, professor of exercise physiology at Kansas State, he said there has not been much research on the physiological reaction to prolonged sitting. Then he rattled off a list of terms you don’t want to hear in a doctor’s office.
“Briefly, what we know now is that sedentary behavior leads to increased triglyceride levels, decreased levels of high-density lipoprotein cholesterol, decreased insulin sensitivity, metabolic syndrome, suppressed lipoprotein lipase activity in skeletal muscle, the enzyme for hydrolysis of triglyceride and decreased bone density,” Harms said. Several labs are studying the death-by-chair phenomenon, and Harms predicts we will know more about the physiology within a few years.
Until that research is complete, all we know is that health risks are associated with -- not caused by, but associated with -- sitting.
What’s the benchmark for too much sitting? Kansas State’s Rosenkranz looked at data from 63,000 middle-aged men, and his team linked time spent sitting and the likelihood of chronic disease. The magic number in the study is four hours. Men who sat for longer than four hours per day were significantly more likely to report having a chronic disease such as cancer, diabetes, heart disease and high blood pressure, compared to men who sat for less than four hours per day. The association with diabetes and hypertension was strongest. The link to cancer is the most tenuous.
Ah, you are thinking, this isn’t a problem for me because I exercise.
Ah, but you are wrong.
You could be in prime shape, but if you sit for extended periods of time, the link between sitting and chronic disease is still present.
Lynette Craft, an adjunct assistant professor in preventive medicine at Northwestern University's Feinberg School of Medicine, and her colleagues found that women who exercise regularly spend as much time sitting as women who don't.
“The relationship between sitting and chronic diseases is independent of the time people spend physically active,” Craft said. “Even when we control for how much physical activity people are getting, the relationship persists. We’re saying, ‘Don’t forget about this other behavior. It could be this silent thing that gets you that you don’t really realize.’”
Correlation or Causation?
The science isn’t settled, so no one can say with certainty that it is sitting that is leading to obesity, diabetes, hypertension and other maladies. It’s possible that people who smoke and drink and don’t get enough sleep and make other similar lifestyle choices also happen to like to sit a lot. Behavior patterns tend to cluster, meaning people who make more than one negative lifestyle choice tend to make many.
Researchers counter by saying that while there may not be certainty, the association is strong.
Van Der Ploeg works at a sit-stand work station and stands when he rides the train. Rosenkranz works at a sit-stand desk. Craft makes herself get up at least once an hour. Hamilton and his team have a program on their computers that reminds them to stand every 15 minutes.
Are the experts right? Is there a link between death, disease and sitting? In the future, will we execute criminals on death row by strapping them into office chairs?
I wrote this entire article while standing up.
Joe Donatelli is a freelance writer. Follow him at joedonatelli.com.
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