It's well worth remembering that regular exercise brings benefits that no present medical technology can match-and at a fraction of the cost of medicines that do far less. EurekAlert! notes that researchers compared "brain scans of older adults who exercise to brain scans of those who do not. ... The researchers recruited 12 healthy adults, age 60 to 76. Six of the adults had participated in aerobic exercise for three or more hours per week over the last 10 years, and six exercised less than one hour per week. All of the volunteers underwent MRI to determine cerebral blood flow and MR angiography to depict blood vessels in the brain. ... researchers were able to make 3-D models of the blood vessels and examine them for shape and size. They then compared the blood vessel characteristics and how they related to blood flow in both the active and inactive groups. The results showed that the inactive group exhibited fewer small blood vessels in the brain, along with more unpredictable blood flow through the brain. ... The active adults had more small blood vessels and improved cerebral blood flow. These findings further point out the importance of regular exercise to healthy aging."