Skipping exercise to do something less active, like sitting to watch TV or sleeping, decreases your memory and thinking ability, according to a new study published in the Journal of Epidemiology and Community Health. UK researchers analyzed data from almost 4,500 adults. They determined that those who skipped exercise in favor of eight minutes of sedentary behavior exhibited 1 to 2 percent decreases in their cognition scores. Although these decreases were small, they show how even minor changes in physical activity can affect your brain health. On the other hand, choosing to exercise for nine minutes instead of sitting or lying down improved cognitive scores 1 percent.