Sitting Disease. It sounds like some mysterious condition you’d bring back from an exotic vacation, but it’s actually a modern homegrown ailment caused by going from the breakfast table to the driver’s seat, from your desk to the car to the sofa for the evening, with little movement otherwise.
The staggering amount of time many of us spend being sedentary-up to 15 hours a day if we work in an office, according to one study-can lead to problems inside and out. You’re probably familiar with the aches and pains caused by hunching over a computer, but spending too much time in a chair or slumped on the sofa also has been linked to several life-threatening conditions, including blood clots, nonalcoholic fatty liver disease, heart disease, and cancer. Not even your brain is spared: In April 2018, researchers published a study that found an association between sedentary behavior and thinning of the regions of the brain that are critical to memory formation.
The issue with sitting goes beyond concern about obesity, although being overweight can increase the risk of many of the same conditions linked to sitting too much. And yes, clocking so many hours in your seat can make it harder to maintain a healthy weight: “When you’re sitting, you’re burning only half the calories you would standing or walking lightly,” says David A. Alter, MD, PhD, chair of cardiovascular and metabolic research at the UHN-Toronto Rehabilitation Institute.
But even if you’re trim, a sedentary lifestyle may still wreak havoc on your health. That’s because “lack of movement affects how we burn fat and metabolize sugar and the body’s response to insulin,” says Dr. Alter. Your cholesterol may also go up, along with markers of inflammation and troponins (a protein produced by cardiac muscle cells when they’re hurt or dying). Such physiological changes can nearly double your odds of diabetes and increase your risk of cardiovascular disease by 14 percent.
In a small study last year, researchers took a group of healthy young adults who regularly clocked at least 10,000 steps a day and had them cut back to 1,500 steps. Participants still went to work and took care of their families, says Dan Cuthbertson, PhD, of the University of Liverpool’s Institute of Ageing and Chronic Disease. It was no surprise that within two weeks, subjects increased total body fat, particularly around their middles, and lost muscle mass. But strikingly, the group also experienced a decrease in insulin sensitivity and an increase in both fat accumulated in the liver and triglycerides. Staying sedentary had consequences that were both swift and potentially serious in the long term. These changes were all reversible when participants resumed their normal activity regularly.
The health effects of sitting too much
Sitting as much as many of us do increases our chance for some 35 serious conditions, likely because getting up and moving around is key for regulating proteins, genes, and other systems that lower our susceptibility to disease. Below, the effects of “sittingitis”:
- Depression and anxiety
The more you sit at work, the greater your risk, even if you exercise, a study in Mental Health and Physical Activity found. On the flip side, other research shows that the more people move throughout the day, the happier they are.
- Back and neck pain
Just four hours of sitting can compress a key disc in your lower back, says Gregory Billy, MD, associate professor of orthopedics and rehabilitation at Penn State University. Poor posture can also lead to disc problems in your neck.
Risk of colon and endometrial cancer goes up even after accounting for exercise, possibly due to inflammation, weight gain, and other changes. One review in the Journal of the National Cancer Institute reports that for every additional two hours per day spent sitting, risk jumps 8 percent and 10 percent for colon cancer and endometrial cancer respectively.
- Obesity, diabetes, and heart trouble
Yes, you burn fewer calories sitting, but also the hormone insulin’s ability to move glucose out of blood and into cells may decline when you sit for long periods, Dr. Alter says. Cholesterol and markers of inflammation may go up; how you metabolize fat changes; and vascular function may be reduced.
- Weak bones
Weight-bearing exercise, including standing and walking, stresses your skeleton in a good way, signaling specialized cells to replace old bone tissue with new. When you sit too much, the body replaces less of what it loses, leading to fragile bones and a greater risk of osteoporosis, especially as you get older.
- Blood clots
Slow blood flow in the legs from a sedentary lifestyle, possibly along with lower levels of clot-preventing proteins, increases your risk. Women who sat for more than 40 hours per week had more than double the risk of a clot moving to their lungs compared with those who sat less than 10 hours.
Can getting more exercise help?
Chairs are hardly a modern invention, but roughly 200 years ago, people sat for just five hours a day. The rest of their waking hours were filled with physical exertion: manually laundering clothes, kneading bread, walking places, working in the garden, you get the idea. If your great-great-great-great-great-great-grandma didn’t swear by her Spin class, it’s as much because she was doing a low-key workout from sunup to sundown as due to the fact that those classes didn’t exist. Today, including eight hours of slumber at night, we may move as little as 60 minutes each day.
Were our ancestors cocooned from the perils of a sedentary lifestyle because they were moving more, or because they weren’t sitting as much? That’s hard to parse, says Dr. Alter. We do know that only 18.7 percent of American women meet the federal guidelines for physical activity (at least 150 minutes of moderate or 75 minutes of vigorous cardio exercise each week).
There’s no question that hitting those targets can help your health and improve your longevity. But it may take more than double that amount of conscious exercise to offset the time you spend sitting: A study in The Lancet that analyzed data from more than 1 million adults found that it took 60 to 75 minutes of moderate cardio per day to wipe out sitting’s higher risk of premature death. And even the most active participants saw an uptick in mortality risk when they sat in front of the TV for five or more hours a day.