The time you spend sitting down might be damaging your arteries. Inactivity may increase the likelihood that calcium in your arteries will harden and increasing the risk for blood clots and heart disease. “Research with middle-aged volunteers found that each additional hour of sedentary time was linked to 12 percent higher odds of having calcium buildup in the coronary arteries, an early sign of coronary heart disease…Overall, the volunteers spent between one hour and 11 hours per day sedentary, and spent between zero and 200 minutes a day doing moderate to vigorous physical activity, with an average of 29 minutes.” This was a small study that was done in a small time frame and therefore while the researchers encourage healthy and active lifestyles, they have not proven that calcium buildup is solely caused by being sedentary.