Boosting your blood flow makes you healthy. Anything that limits blood flow such as stress, caffeine, nicotine, drugs, alcohol, lack of sleep or excercise is unhealthy.
Blood is especially important to the brain. Even though the brain is composed of only 2 percent of the body's weight, it uses 20 percent of the body's blood flow and oxygen supply. Blood flow to the brain is rarely thought about as important by the general public, unless a disaster strikes, such as a stroke or an aneurysm. Yet good blood flow is absolutely essential to the brain's health. A SPECT test specifically looks at blood flow in the brain.
Blood brings oxygen, sugar, vitamins, and other nutrients to the brain and takes away carbon dioxide and other toxic waste products. Anything that limits blood flow prematurely ages all of you body's organs.