Why Is Sitting so Bad for Us?

For many people, work means hours and hours of sitting, with rare pauses for a walk around the block or even down the hall. While it’s easy to dismiss this as a routine part of adult life, it is becoming a growing concern among researchers. Studies suggest that spending hours in a chair can cause all kinds of damage to your body, and even shorten your lifespan.

Last year the Annals of Internal Medicine published a study of 8,000 adults that showed an association between prolonged sitting and a risk of early death from any cause. (People who sat for no more than 30 minutes at a time had the lowest risk in that study.) Other research has linked prolonged sitting or other sedentary behavior to diabetes, poor heart health, weight gain, depression, dementia, and multiple cancers.

It's a habit that seems to start early. One of the most recent studies, published in JAMA, found that in more than 51,000 Americans surveyed, the amount of time spent sitting increased in a range of age groups by about an hour a day between 2007 and 2016, and that included a notable rise among adolescents.

“Prolonged sitting is one of the main causes for many of the conditions treated in my musculoskeletal clinic. It often results in office visits with other types of doctors as well,” says Eric K. Holder, MD, a Yale Medicine physiatrist (a physician who specializes in the nonsurgical care of patients with musculoskeletal issues). “It is so ingrained in our society now—people are stationed at desks, seated in front of computers or the TV for extended periods, constantly traveling in cars, trains, and on planes. It’s a major health problem that can lead to many chronic diseases.”

We asked five Yale Medicine specialists how prolonged sitting could be affecting your health and what you can do about it.

If your lower legs and feet get tired, swollen, and achy, you could be experiencing blood and fluid pooling in those areas after a long period of sitting, says Britt H. Tonnessen, MD, a vascular surgeon. In the worst cases, you can develop deep vein thrombosis (DVT). This is when a blood clot forms in a deep leg vein, which is dangerous because it can travel to the lung. “Blood clots tend to originate for three reasons,” Dr. Tonnessen says. A blood disorder can make a person prone to clotting, while an injury or related trauma may also raise risk for DVT. But the third reason – the one over which we all have control—is stasis, being still or sedentary. Women who are pregnant or taking birth control, elderly people, and people who smoke are at especially high risk, says Dr. Tonnessen. “Not exercising or moving around on occasion can lead to a more extensive blood clot.”

Dr. Tonnessen’s advice: “Take steps now. First, tell your doctor if you have risk factors for blood clots, especially if an immediate family member has had a clot in the legs or lungs at a young age, so you’ll better understand your risk. Then, whether you have a family history or not, move around every 30 minutes or hour to pump the blood out of your calf muscles. Take a short walk. Do something, anything.”

Another suggestion: “Try wearing elasticized compression stockings [15 to 20 or even 20 to 30 mm Hg]. Medical professionals often wear these; they stretch from foot to knee and can help, especially if you are experiencing leg aches, swelling, or restless legs. These stockings are comfortable and take away that tired feeling and achiness.”

Prolonged sitting puts significant stress on spinal structures as well as other joints, such as the shoulders and hips, especially when sitting with poor posture, says Dr. Holder. “When we sit at our computers, we often slouch, craning our necks forward which, over time, can lead to persistent postural misalignment. Sitting can also lead to overall deconditioning, early muscle fatigue, weakened core stabilizers, and tightening of the hip flexors, resulting in increased stress on your low back and reduced spine flexibility. It also affects the gluteal buttock muscles over time, leading to deactivation and weakening of these muscles,” he says. Sometimes this is referred to as gluteal amnesia, which can lead to low back pain and hip pain. He also notes that inactivity and prolonged sitting can lead to weakening of the bones (osteoporosis). The government’s recommendation of at least 150 minutes a week of moderate aerobic activity for people ages 18 to 64 can help, says Dr. Holder, but it may not be enough as prolonged sitting can negate all of that exercise. “It is important to move frequently throughout your day to counteract the negative effects of sitting.”

Dr. Holder’s advice: “Take stock of your office workstation. Make sure you have an ideal ergonomic setup. A sit-to-stand desk is a great option to decrease your sit time. If a standing desk is not available, you can move your laptop or desktop computer to a high counter. When sitting, consider using a lumbar roll (or a rolled-up towel) placed at the small of your back, between your back and the chair to improve alignment. For the more adventurous, consider a treadmill desk.”

More advice: “If a standing desk is not an option, I usually recommend getting up every 30 minutes or so to move and stretch. Instead of sending an email to your co-worker down the hall, discuss the issue with them in person. Use a smaller water bottle that requires you to walk to the cooler to fill it more frequently throughout the day. A pedometer to monitor your steps is also a great way to keep track of your activity, especially if you share step counts with friends or co-workers to keep each other motivated. If you’re watching TV at home, take standing, walking, and stretching breaks during commercials. I am a fan of any healthy motivational tool to keep you up and moving throughout the day—movement is medicine.”

It’s clear that sitting—like a lack of physical activity in general—is a contributing factor in many cases of cardiovascular disease, which is the leading cause of death in both men and women, says cardiologist Rachel Lampert, MD. “The body has all kinds of negative reactions to sitting for long periods,” she says. “In addition to decreasing the blood flow to the legs, sitting impacts things like sugar regulation and blood pressure—by altering the normal function of blood vessels, it feeds into diabetes and heart attacks. We know that the more you sit, the more likely you are to have a heart attack or die from a cardiac cause,” says Dr. Lampert. “It’s an independent contributor, along with how much physical activity you are getting.” Other considerations in heart health are body mass index and waist circumference—in both cases the numbers will go up the longer you sit.

Dr. Lampert’s advice: “There is no exact formula for how often you should stand up from your desk. But it makes sense to increase the amount of time you are active, whatever you’re doing. Even a short walk every hour is helpful. Many people track their habits and increase their activity once they have clear evidence of their sedentary behavior, too. Anyone can use a step-counting device such as a Fitbit or a mobile device reminder app [free and low-cost ones are available].”

Some studies show an association between prolonged sitting and weight gain—and an especially strong link with diabetes, says Wajahat Mehal, MD, director of the Yale Medicine Metabolic Health & Weight Loss Program. This makes sense, he adds. “If you go back 100 years, movement was a constant part of our lives. If you wanted water, you’d have to go out to the well. If you wanted to talk to a neighbor, you’d walk next door.” Today, people eat at their desks or in front of a TV set, where they are distracted while eating their food. This puts them at risk for eating larger portions, and portion control is key to keeping weight down, he says.

Dr. Mehal’s advice: “Give your food undivided attention. Don’t eat your lunch at the same time you are browsing online, reading the news, or watching YouTube. When we do that, we have the meal, but it doesn’t fully register, because our mind is distracted.”

Another bit of advice: “Have varied types of physical activity. Some get too focused on super-vigorous cardiovascular exercise. This is fine, but it is a mistake to think that unless you’re working out like an Olympic athlete, it doesn’t count. The truth is that a comfortable 15- or 20-minute walk accomplishes a lot when done regularly.”

Sitting at work and a sedentary lifestyle, in general, both appear to be independent contributors to cancer, just like eating too much red meat or smoking, says Xavier Llor, MD, PhD, co-director of the Smilow Cancer Genetics & Prevention Program and medical director of the Colorectal Cancer Prevention Program. “What we need is a general culture change,” he says.

Dr. Llor’s advice: “Do as much of your job standing as possible and move as much as you can beyond that. Extra weight is a cancer risk and standing burns twice the number of calories as sitting. It’s definitely challenging. We all have jobs to do and many people don’t have that much time. So, do as much as you can. The key is to foster and promote a healthy lifestyle in general. This includes regular physical exercise, not smoking, minimizing alcohol and meat, and eating enough fruits and vegetables.”