People who spend excessive amounts of time sitting are more prone to injury and are at risk for circulation and mobility problems. Sitting for prolonged periods, especially without proper posture, fatigues the muscles and compresses the blood vessels responsible for supplying the muscles with blood. If you must spend a significant amount of time sitting at work or home, change positions frequently and use an ergonomic chair. Purchase a chair with a comfortable seat cushion that allows you to easily adjust the seat tilt and height and the angle and height of the backrest. The seat should be large enough for both legs to fit comfortably side by side without any pressure on the sides of your thighs or on the backs of your knees. Sit with your back in a naturally straight position. Do not force your spine into an unnatural posture as this actually shortens your spine and interferes with circulation. Your spine should not bend toward the front of your body, and there should be no noticeable hollow between your lower back and the chair.
Center your head over the top of your spine in a relaxed and slightly forward position. Use the backrest of your chair for support. Place your feet flat on the floor or on a footrest if your legs are too short to reach the ground. Sitting with your feet dangling or tucked underneath your body can impair circulation to your lower legs and feet, leading to swelling and varicose veins. Keep your ankles even with or slightly in front of your knees. Sit on a pillow if your chair is still too low even after you adjust its height. Sitting on a low chair can cause your legs to bend at an unhealthy angle, interfering with blood circulation and causing leg swelling. It also can put unnecessary pressure on your buttocks and internal organs. Walk around for several minutes out of every hour. Walking encourages your heart to pump faster and harder and increases blood flow to your extremities. It will also help minimize blood pooling in your legs. Moving your arms and legs around while sitting is also beneficial to circulation.
Use padded armrests if you must hold your arms extended from your body for a significant length of time and need the support. Place the fleshy part of your arms against the armrest and move them around frequently to encourage blood flow. Avoid crossing your legs while sitting as this can reduce blood flow to your legs and feet. Crossing and uncrossing your legs while sitting can redistribute pressure and encourage the pumping of blood through the tissues in your legs.The only limit to our realization of tomorrow will be our doubts of today.Muscles burn less fat and blood flows more sluggishly during a long sit, allowing fatty acids to more easily clog the heart. Prolonged sitting has been linked to high blood pressure and elevated cholesterol, and people with the most sedentary time are more than twice as likely to have cardiovascular disease than those with the least. 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.
A 2011 study found a decline in insulin response after just one day of prolonged sitting. 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 is that regular movement boosts natural antioxidants that kill cell-damaging — and potentially cancer-causing — free radicals. When you stand, move or even sit up straight, abdominal muscles keep you upright. But when you slump in a chair, they go unused. Tight back muscles and wimpy abs form a posture-wrecking alliance that can exaggerate the spine's natural arch, a condition called hyperlordosis, or swayback. Flexible hips help keep you balanced, but chronic sitters so rarely extend the hip flexor muscles in front that 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. Sitting requires your glutes to do absolutely nothing, and they get used to it.
Soft glutes hurt your stability, your ability to push off and your ability to maintain a powerful stride. Sitting for long periods of time slows blood circulation, which causes fluid to pool in the legs. Problems range from swollen ankles and varicose veins to dangerous blood clots called deep vein thrombosis (DVT). Weight-bearing activities such as walking and running stimulate hip and lower-body bones to grow thicker, denser and stronger. Scientists partially attribute the recent surge in cases of osteoporosis to lack of activity. Moving muscles pump fresh blood and oxygen through the brain and trigger the release of all sorts of brain- and mood-enhancing chemicals. When we are sedentary for a long time, everything slows, including brain function. If most of your sitting occurs at a desk at work, craning your neck forward toward a keyboard or tilting your head to cradle a phone while typing can strain the cervical vertebrae and lead to permanent imbalances. The neck doesn't slouch alone.
Slumping forward overextends shoulder and back muscles as well, particularly the trapezius, which connects the neck and shoulders. When we move, soft discs between vertebrae expand and contract like sponges, soaking up fresh blood and nutrients. But when we sit for a long time, discs are squashed unevenly. Collagen hardens around tendons and ligaments. 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. People who watched the most TV in an 8.5-year study had a 61 percent greater risk of dying than those who watched less than one hour per day. Hours of TV per day If you have to sit often, try to do it correctly. As Mom always said, "Sit up straight." • Not leaning forward • Arms close to sides
• Elbows bent 90° • Lower back may be supported • Feet flat on floor Sitting on something wobbly such as an exercise ball or even a backless stool to force your core muscles to work. Sit up straight and keep your feet flat on the floor in front of you so they support about a quarter of your weight. Stretching the hip flexors for three minutes per side once a day. Walking during commercials when you're watching TV. Even a snail-like pace of 1 mph would burn twice the calories of sitting, and more vigorous exercise would be even better. Alternating between sitting and standing at your work station. If you can't do that, stand up every half hour or so and walk. Trying yoga poses — the cow pose and the cat — to improve extension and flexion in your back.Scientists interviewed for this report James A. Levine, inventor of the treadmill desk and director of Obesity Solutions at Mayo Clinic and Arizona State University. Charles E. Matthews, National Cancer Institute investigator and author of several studies on sedentary behavior.