Sitting causes overall slower blood flow and weakened heart muscles, leading to higher blood pressure and chronic inflammation in the blood vessels. The combination of unhealthy accumulation of body fat and reduced muscle mass results in higher levels of unhealthy fats in the blood, increasing the risk of heart attack and stroke. Those who sit for more than seven hours a day have an 85% increased risk of dying from cardiovascular disease. For every two hours a person sits each day, the risk of cardiovascular disease increases cardiovascular diseases by another 5%.

Sitting at a desk with slumped shoulders and a rounded spine results in a significant reduction in lung capacity, which is compounded by the lack of movement of the diaphragm due to the compression of the abdomen between the torso and the flexed hip. Over time, breathing becomes chronically impaired, which leads to decreased energy and negative effects on brain function, including impaired concentration and memory, and surprisingly an increased risk of stroke.

Sitting causes food to be compressed in the gut, which impairs digestion and can lead to long-term, low-level inflammation in and around the gut That, in turn, negatively impacts healthy gut flora (microbiome). This is associated with gut disease and may also contribute to allergies, asthma, metabolic syndrome, heart disease, and cancer.

Sitting for too long affects the hormones dopamine and leptin, which play important roles in regulating hunger and satiety. Weight gain caused by inactivity can initiate a vicious cycle in which it becomes increasingly difficult to lose weight. Being overweight increases your risk of a number of serious conditions, including diabetes, high blood pressure, heart disease and heart attack, stroke, cancer, kidney disease, and liver disease; it can also disrupt sleep and cause a range of musculoskeletal problems.

Sitting for more than 8 hours a day increases the risk of lung cancer by 54%, uterine cancer by 66%, and colon cancer by 30%. This is partly due to hormonal changes (IGF-1), excessive insulin secretion, a state of constant underlying inflammation and reduced production of antioxidant enzymes. The risk of dying from cancer is increased by 82% for people who sit more than 11 hours a day.

The body's ability to effectively respond to sugar intake is severely compromised by prolonged sitting, leading to insulin resistance and diabetes. Long-term elevated blood sugar levels lead to cardiovascular disease, stroke, kidney failure, nerve damage, blindness, and limb amputations .