We know sitting too much is bad for our health. It’s normal to feel a little guilty after a long TV binge or work day at a desk job. But what exactly happens to our bodies when we sit for nearly eight hours per day, which is what the average U.S. adult does? Many things, and the chain of problems are from head to toe.
Impacts on the organs:
Heart
Muscles burn less fat and blood flows more sluggishly during a long sit. Prolonged sitting has been linked to high blood pressure and elevated cholesterol, and people with the significantly higher sedentary time are more than twice as likely to have cardiovascular disease than those with the least.
Pancreas
The pancreas produces insulin, a hormone that carries glucose to cells for energy. But cells in idle muscles don’t respond as readily to insulin, so the pancreas produces more and more, which can lead to diabetes and other diseases.
Colon
Studies have linked sitting to a greater risk for colon, breast and endometrial cancers. The reason is unclear, but one theory is that excess insulin encourages cell growth. Another theory is that regular movement boosts natural antioxidants that kill cell-damaging, and potentially cancer-causing, free radicals.
Impacts on the muscles:
Abs
When you stand, move or even sit up straight, abdominal muscles help keep you upright. But when you slump in a chair, they are not activated. Tight back muscles and weak abs wreck your posture and can exaggerate the spine’s natural arch, a condition called hyperlordosis, or swayback.
Hips
Flexible hips help keep you balanced, but chronic sitters rarely extend the hip flexor muscles, and they become short and tight, limiting range of motion and stride length. Studies have found that decreased hip mobility is a main reason elderly people tend to fall.
Glutes
Sitting requires your glutes to do absolutely nothing, and they get used to it. Weak glutes reduce your stability, your ability to push off and your ability to maintain a powerful stride.
Impact on the legs:
Poor circulation
Sitting for long periods of time slows blood circulation, which causes fluid to pool in the legs. This can cause swollen ankles, varicose veins and dangerous blood clots called deep vein thrombosis (DVT).
Soft bones
Weight-bearing activities such as walking and running stimulate hip and lower-body bones to grow thicker, denser and stronger. Scientists partially attribute the surge in cases of osteoporosis to general lack of activity.
Impact on the upper body and spine:
Brain Fog
Moving muscles pump fresh blood and oxygen through the brain and trigger the release of all sorts of brain- and mood-boosting chemicals. When we are sedentary for a long time, everything slows, including brain function.
Strained neck
If most of your sitting occurs at a desk at work, craning your neck forward toward a screen or tilting your head to cradle a phone while typing can strain the cervical vertebrae and lead to permanent imbalances.
Shoulders and back
The neck doesn’t slouch alone. Slumping forward also overextends the shoulder and back muscles, particularly the trapezius,
Inflexible spine
Spines that don’t move become inflexible and susceptible to damage in mundane activities, such as when you bend to tie a shoe. When we move around, disks between vertebrae expand and contract like sponges, soaking up fresh blood and nutrients. When we sit for a long time, disks are squashed unevenly and lose sponginess. Collagen hardens around supporting tendons and ligaments.
Disk damage
People who sit more are at greater risk for herniated lumbar disks. A muscle called the psoas travels through the abdominal cavity and, when it tightens, pulls the upper lumbar spine forward. Upper-body weight rests entirely on the ischial tuberosity (sitting bones) instead of being distributed along the arch of the spine.