Sitting for a long time comes with several health risks, especially if the sitting is done for more than four hours at a time without interruption. Besides the stiffness and muscle fatigue that accompanies sitting, many serious health problems, such as increased risk of disease and injury, can develop if sitting is done for too long over many years.
Sitting for extended periods of time without alternating the body's position can affect the muscles in the torso, neck and shoulders. Because the muscles in these parts of the body must be held in a somewhat fixed position while sitting, the blood vessels are squeezed and blood flow is reduced to these places, causing fatigue. This muscle fatigue also can contribute to overall exhaustion and stiffness.
Lowered Blood Circulation
Besides increasing muscle fatigue, the lowered blood circulation that accompanies sitting also can lead to a host of other problems. Blood often pools in the lower legs, resulting in numbness and varicose veins.
Decreased Fitness and Risk of Fatality
Over time, those who must sit for many hours at a time are more likely to experience decreased fitness, a lower heart rate and a higher risk for injury and disease, especially those who also have little to no physical activity in their lives. A study conducted in 2009 by the Pennington Biomedical Research Center in Baton Rouge found that out of 17,000 Canadians tracked for 12 years, those who sat the most had the highest risk of fatalities. People who sit for too long are more likely to be overweight and have a high risk of heart attack.
Increased Risk of Chronic Back and Neck Injuries
Sitting for a long time places a high amount of stress on the spine, specifically in the lower back and neck regions. Over time, sitting can result in compression of the spinal discs that leads to compromised spinal nutrition and lowered back health. Additionally, because muscles in the back and neck become tightened from pressure, sudden movements in these areas can lead to injury.
Increased Risk of Diabetes
Although sitting for too long is not a sure indicator of diabetes, it does make the sitter 26 percent more likely to develop metabolic syndrome, a condition that often leads to diabetes, according to a 2010 article published in the British Journal of Sports Medicine.