For years, we’ve reported on the myriad dangers of sitting, from heart woes to belly fat to a permanent man-shaped indentation in your couch. In fact, Australian researchers estimate that nearly 6 percent of all deaths can be attributed to total sitting time per day, even after physical activity is taken into account—a figure similar to that of smoking or carrying extra pounds.
But it turns out sitting is doing a lot more to your body than just the more obvious damages. You might want to stand up before reading about these five surprising effects.
1. It Puts You in a Mind Funk
An Australian study found that men who sat for more than 6 hours per day at work were 90 percent more likely to report moderate levels of psychological distress—say, feeling tired, nervous, restless, or hopeless—than those who parked it for less time. This relationship held true even when the researchers took into account their physical activity outside of work.
The reason for the mental health effects aren’t yet well understood, says study author Michelle Kilpatrick, Ph.D.(c). But it’s likely a two-way street, meaning that poorer mental health can cause people to be more sedentary and sedentary behaviors can also directly influence what’s going on in your mind.
2. It Raises Your Cancer Risk
Sitting really can be sinister: A German meta-analysis concluded that people who sat for the longest period each day were 24 percent more likely to develop colon cancer than those who logged the least butt time. And the risk was even higher for those who vegged out in front of the tube.
When you sit, you’re not engaging in the light physical activity—like standing, walking, or just puttering about—that increases calorie burn. This can contribute to obesity, which has been linked to the development of cancer growth, the researchers say.
3. It Makes Your Blood Sugar Spike Harder
Staying seated too long can lead to steeper spikes in your blood sugar. A study from New Zealand found that people’s insulin and glucose levels were significantly higher when they sat for 9 hours straight than when they engaged in a little activity all at once before sitting, or when they broke up their activity into smaller, more frequent bouts. And that’s important, since better blood sugar control is associated with decreased risk of developing diabetes.
Interestingly, interrupting the 9-hour sitting fest with 18 short walking breaks controlled insulin and glucose better than performing all the activity in a 30-minute chunk. The researchers believe that the frequent activity bouts burned more carbs, which helped clear glucose from the blood.
4. It Promotes Sticky Blood
A Danish study found that people who worked in sedentary, cramped positions—like bus drivers or forklift drivers—were 28 percent more likely to be treated for a serious blood clot in the lungs called a pulmonary embolism than those who worked in active but socioeconomically similar jobs.
The researchers believe that certain cramped sitting positions may prevent movement of the legs, leading to a decrease in circulation and a potential increase in clots.
5. It Can Leave You Vulnerable to Back Pain
Your back probably doesn’t feel great after a day plopped in front of the computer, and that positioning might actually increase your risk of pain problems down the line. A Penn State study found that sitting without interruption for as little as 4 hours can cause compression of certain disks in your lower back. Over time, this pressure may lead to disk degeneration—one of the most common causes of lower back pain.
