Humans are built to move. Our bodies are designed to be mobile and our physiological systems work best when we are. Of course, the jobs we most often have and the lifestyles we most often live don’t promote the movement our bodies need. According to the American Heart Association , we should be moving with moderate intensity for at least 150 minutes every week. The Centers for Disease Control and Prevention reports, however, that only 23% of Americans are getting that amount of exercise.

We’re hearing more and more from health professionals about just how bad prolonged immobility, especially sitting, is for us. Britain’s National Health Service explains that evidence on the subject goes back to the 1950s, “when researchers found double decker bus drivers were twice as likely to have heart attacks as their bus conductor colleagues. The drivers sat for 90 per cent of their shifts, the conductors climbed about 600 stairs each working day.”

A 2018 study from the American Journal of Epidemiology found the links between a sedentary lifestyle and early mortality to be much more comprehensive. It explains that “prolonged leisure-time sitting” is “associated with higher risk of mortality from all causes.” If you’re the kind of person who finds fear to be a good motivator, let’s delve into how our sedentary ways put us at risk for some major health concerns.

Without regular muscle contractions in your leg muscles to help blood flow back to your heart, your circulatory system is compromised, meaning blood can pool in your legs. This pooled blood puts stress on your leg veins, which can extend them and create varicose veins.

Many people don’t like the look of varicose veins on their legs, but they’re not usually a health concern. More troubling is the risk of developing deep vein thrombosis, which is a blood clot that forms in a leg vein as a result of blood not circulating properly. Blood clots, of course, are a serious issue that can become a medical emergency if they move to the heart or lungs.

Muscle weakening can result from sitting for long periods, especially, as you might expect, in your back, legs, hip flexors and gluteal muscles. Weakened muscles in general can pose risks, especially for an aging population, because they increase the chance of strains, injuries and falls.

People who sit for long periods every day frequently report back and joint issues, especially when sitting is coupled with the bad posture so many of us have. In

Dr. R.J. Burr writes that “tension and imbalance in your back and neck” caused by poor seated postures can “start a cascade of events” that can lead to serious spinal issues.